Four months after Hurricane Gilbert we resampled 10 habitats that were sampled previously in December 1987. Overall, we found no change in the total number of species nor in the mean number of individual birds detected. The mean number of individuals declined in three montane habitats (cloud forest, pine plantation, and coffee plantation), where structural damage to tree trunks and branches was often severe, and trees were still defoliated. In the mountains, higher proportions of nectarivores and fruit/seedeaters declined than insectivores. We found increased mean numbers of individuals in two lowland sites (wet limestone forest and mangroves), where structural damage to trees was also severe, but where new foliage was present. Mean numbers of individuals did not change in five other lowland habitats, despite varying levels of vegetation damage. Populations of several species declined in some habitats and increased in others, a pattern consistent with interhabitat migration. Population declines in montane habitats were related to diet, suggesting that Hurricane Gilbert's greatest stress on Jamaica's montane bird populations occurred after its passage rather than during its impact. Frequent hurricanes may contribute to some of the commonly observed characteristics of the Caribbean avifauna. Received 5 March 1991, accepted 10 July 1991.
'Institute of Tropical Forestry, Southern Forest Experiment Station, USDA Forest Service,
P.O. Box B, Palmer, Puerto Rico 00721; and
Department of Biology, University of Puerto Rico, Cayey, Puerto Rico 00633, USA; and
2Terrestrial Ecology Division, Center for Energy and Environment Research, GPO Box 363682,
University of Puerto Rico, San Juan, Puerto Rico 00936, USA.
IN SOME tropical regions, hurricanes occur
with sufficient frequency to be important fac-
tors in determining the structure and species
composition of biotic communities (e.g. Wads-
worth and Englerth 1959, Odum 1970). For bird
populations in particular, hurricanes can have
both direct and indirect effects (for recent re-
view, see J. Wiley, unpubl. manuscript). Direct
hurricane effects include death from exposure
to high winds and rain (Kennedy 1970). Indi-
rect effects of hurricanes on bird populations
include destruction of food supplies (or nesting,
roosting, and foraging substrates) by the storm's
high winds (Jeggo and Taynton 1980). Further-
more, storm-weakened birds may be at greater
risk to predation, particularly in the absence of
vegetative cover or roosting sites for protection
(Engstrom and Evans 1990). Hurricanes can dis-
rupt normal migration patterns and, in some
instances, change the geographic distributions
of species (Thurber 1980). Following hurri-
canes, humans may kill weakened birds and
accelerate the rate of habitat destruction
(Thompson 1900).
The difficulty with much of the previous lit-
erature on hurricane effects on bird populations
is its anecdotal nature and the absence of prior
baseline data for quantitative comparison after
the storm's impact (but see Lynch 1991a, b, As-
kins and Ewert 1991, Waide 1991). Another
problem is that a variety of habitats or sites is
rarely surveyed and, thus, it is difficult to assess
overall population or community changes after
a hurricane. Our study takes advantage of base-
line samples of bird populations and vegetation
structure gathered in 10 habitats in December
1987, prior to the arrival of Hurricane Gilbert
in Jamaica. We replicated our baseline mea-
surements in these same sites in January 1989,
four months after the storm's passage, to eval-
uate the short-term effects of the hurricane on
vegetation structure and terrestrial bird popu-
lations. Vegetation measurements provided us
with an indication of the storm's damage at each
of the sites where we counted birds. Here we
describe the effects of a hurricane on avian pop-
ulations before major plant successional changes
took place.
Hurricane Gilbert reached hurricane force on
10 September 1988 approximately 363 km
southeast of the Dominican Republic. It side-
swiped Puerto Rico and Hispaniola, and then
struck Jamaica on 12 September. Hurricane Gil-
bert arrived at 1700 with minimum sea-level
pressure of 960 mbars and sustained winds of
205 kph, with gusts of up to 226 kph. Over
700 mm of rain fell over the interior mountains
of the island from 10-12 September. After leav-
ing Jamaica, Hurricane Gilbert became the most
powerful storm recorded in the Western Hemi-
sphere in this century (Lawrence and Gross
1988). Damage caused by Gilbert to Jamaican
forests was widespread and severe (Jamaica
Natural Resources Conservation Department,
unpubL report; Varty 1991, Bellingham et aL
1992), causing local observers to believe that
bird populations might have been seriously re-
duced (Haynes-Sutton 1988, Gosse Bird Club
1989). Although Gilbert was an intense hurri-
cane, Gupta (1975, 1988) has shown that storms
of this magnitude are common, and even larger
ones have occurred in Jamaica's past.
METHODS
Vegetation.--We sampled I0 typical Caribbean hab-
itats (Appendix I). We used two to four 16-m-diameter
circular plots (0.02 ha) to quantify vegetation in each
habitat. Two plots were placed in vegetation repre-
sentative of areas in which bird point counts were
made. Occasionally, additional plots were located near
the mist nets or in areas representing the extremes
of vegetation structure in variable habitats. After the
hurricane, we attempted to measure vegetation in the
same locations as the prehurricane plots. Pre- and
posthurricane plots were considered to be well
matched when the original center tree could be found
or, alternatively, if: (I) there was greater than 80%
similarity in the number of trees in every diameter
class; (2) the number and diameters of trees recorded
by species or life form were the same (e.g. standing
dead, palms, tree ferns, miscellaneous, dicots); and (3)
the understory species or life forms were the same
(i.e. grasses, forbs, ferns, bamboo, ginger and cacti).
We obtained matched pairs of pre- and posthurricane
plots in montane cloud forest (4 of 4 sites), montane
pine plantation (I of 2 sites), montane coffee (2 of 2
sites), dry limestone forest (2 of 2 sites), dry limestone
ruinate (I of 3 sites), wet limestone forest (I of 3 sites),
lowland coffee with mimosaceous overstory (2 of 2
sites), lowland second growth forest (I of 3 sites), and
mangroves (2 of 4 sites).
Stems of all standing and hurricane-felled trees and
saplings greater than or equal to 3 cm diameter were
measured 1.3 m from the base (dbh) and were re-
corded in diameter classes (dbh) of: 3-8 cm; >8-15
cm; >15-23 cm; >23-38 cm; and >38 cm. We also
classified each tree according to life form or species
as noted above, and. according to the type of structural
damage from the hurricane. Damage classes (from
most to least severe) were: trunk broken; trunk down
(uprooted with trunk or branches on the ground);
trunk leaning (partially uprooted); and presence of
major branch breaks (branches >10 cm diameter;
branch breaks recorded in all habitats except montane
cloud forest). If an individual tree had more than one
type of damage, then only the most severe damage
was used in the analysis. Damage data were pooled
from all posthurricane plots in each habitat, except
in wet limestone forest where damage varied signif-
icantly among plots.
Foliage-height profiles were determined at 20 points
located at !.6-m intervals along the north, south, east
and west radii of the circular plot (after Schemske
and Brokaw !98!). A 3-m pole (2.0 cm diameter)
marked at 0.5-m intervals was placed vertically at each
sample point. We recorded the presence or absence
of foliage touching the pole within each height class.
For height intervals above 3 m, we sighted along the
pole and recorded the presence/absence of foliage in
each of the following estimated height intervals: 3-
4, 4-6, 6-8, 8-10, 10-12, 12-15, 15-20, 20-25, and 25-
30 m. We measured heights of !0 canopy trees in the
plot with optical range finders. According to these
measurements, we overestimated the heights of the
tallest trees using the canopy-profile method in 2 of
the 42 plots; the data from the upper two categories
of the canopy-height profiles in those plots, therefore,
were moved to the next-lower height interval. For
each height interval, we calculated percent cover by
dividing the number of points in which foliage was
present in that height interval by the total number
of sample points (n = 20) and multiplying by I00.
Pre- and posthurricane foliage-height profiles are
shown on the same graph only if they represent a
matched pair. When there was more than one matched
pair of pre- and posthurricane measurements, only
one plot is shown as determined by a coin toss.
Foliage-height profiles were used to analyze changes
in both the amount of foliage and its distribution.
Friedman tests (nonparametric equivalent of an
ANOVA) were used to determine if there were dif-
ferences among all plots in the amount of foliage
present for a given habitat, including pre- and post-
hurricane measurements (two-tailed tests). If signif-
icant or suggestive differences (P < 0.1) in the amount
of foliage were found, then we quantified possible
hurricane-induced changes in the amount of foliage
by comparing the number of height intervals in which
the frequency of foliage intercepts increased or de-
creased in a plot. We used one-tailed sign tests for
each plot (matched pre- and posthurricane pairs) to
evaluate the null hypothesis that there was no de-
crease in the amount of foliage after the hurricane.
Understory vegetation was somewhat weighted in
this analysis, because there were more height classes
in the understory than in the overstory. Possible hur-
ricane-induced changes in the distribution of foliage
within a plot were analyzed by comparing pre- and
posthurricane foliage-height profiles for each plot,
using contingency chi-square tests. This test is insen-
sitive to the amount of foliage present.
Bird censuses.--We surveyed from 5-23 December
1987 before the hurricane, and 22 January to 2 Feb-
ruary 1989 after the hurricane. We modified the fixed-
radius point count method of Hutto et al. (1986) after
taking preliminary counts to determine the effective-
ness of the technique in three different habitats in
Puerto Rico. A single observer recorded all birds seen
and heard during a 10-min period at each point. Counts
were initiated at sunrise and terminated before 1200,
with most counts completed before 1100. Each point
was at least 100 m from all others and not closer than
25 m from a habitat edge. We attempted to complete
30 point counts per habitat, but frequently the size
of the habitat limited the number of point counts
(summarized in Appendix 2). Two observers, moving
in opposite directions, each independently made 15
point counts on the same morning in the same habitat.
In dense habitats, we sampled from trails or roads
and, frequently, used trails to travel through a habitat.
In open habitats, we used a compass to follow a tran-
sect.
For each bird observed during a point count, we
estimated the minimum distance from the observer.
Those birds that were heard but not seen were tallied
in one of two categories: -<25 m from the observer;
or >25 m from the observer. Before sampling in Ja-
maica, we chose 25 m as the radius within which we
could detect all individuals in all but the most dense
habitats.
We calculated the mean number of detections per
25-m-radius point count for each species in each hab-
itat both before and after the hurricane. We compared
the before and after samples for each species in each
habitat with a Mann-Whitney U-test. For each habitat
we tallied the number of species that increased,
showed no change, or decreased after the hurricane.
The diet of each species was classified as either nectar,
fruit/seeds, or insects on the basis of Lack (1976) and
Faaborg (1985). This information was analyzed in a
three-way table using a log-linear model (Sokal and
Rohlf 1981) to test for the presence of a three-factor
interaction among habitat (10 habitats), diet (two diet
types: plant or insect), and population trend (two trend
categories: increase/no change or decrease). The log-
linear model was then used to test for conditional
independence, as well as two-factor interaction. A
probability of type I error of 0.05 or less was accepted
as significant, but we show greater values for descrip-
tive purposes. Throughout the text, we use standard
errors to describe variation around the mean.
Appropriate control sites to monitor changes in bird
populations in the absence of a hurricane between
1987 and 1988 could not be located on Jamaica, be-
cause all sites on the island sustained at least some
hurricane damage. Therefore, as a control to examine
changes in bird populations in the absence of a hur-
ricane between 1987 and 1988, we used two sites on
the island of Puerto Rico. Wunderle conducted point
counts in a Puerto Rican lowland pasture and mon-
tane second-growth forest in November 1987 and 1988.
Point counts in the control sites were run in the same
manner as in Jamaica, except that two consecutive
mornings were required per site (15 counts/morn-
ing).
The lowland-pasture control site located in Salinas,
Puerto Rico, was drier and contained more mesquite
(Prosopis julifiora) than the lowland pasture in Jamaica.
However, the two pasture sites have similar avifau-
nas, with 12 genera and 8 species in common. The
montane second-growth forest site at 720 m near Car-
ite, Puerto Rico, was at a lower elevation and had
more shrubby vegetation than the montane cloud for-
est at Hardwar Gap, Jamaica. Similarities exist in the
avifauna of the two montane sites in that they share
16 genera and 8 species.
Mist-net sampling supplemented the point counts
in 6 of the 10 habitats in Jamaica. We used 12-m nets
with 30-mm mesh and four shelves, set to a height
of 2.5 m, usually in a continuous line. The number
of nets ranged from 15 to 20 per site. We usually set
nets during the afternoon and then opened them at
sunrise on the following day; nets were kept open
until late afternoon (with the exception of the man-
grove site after the hurricane). Morning netting was
simultaneous with point counts in each habitat. After
the hurricane, we attempted to set nets in the exact
location as earlier, but this was impossible in some
cases because of extensive damage to the site. In wet
limestone forest and mangroves, we set nets 15-20 m
from their prehurricane positions.
We used mist-netting data to estimate population
abundance before and after the hurricane in each of
the sampled habitats using a modification of the
method of Terborgh and Faaborg (1973). For each
habitat and each netting session, we regressed the
number of new captures per 15 net hours against the
cumulative net hours of sampling effort. From the
Y-intercept we obtained an estimate of the projected
capture rate. In addition, we show the slopes of the
regression before and after the hurricane in each hab-
itat. The slope of the regression provides a measure
of overlap in foraging range; a steep negative slope
indicates little overlap. We compared the mist-netting
results with those of the point counts, but did not
analyze them statistically because of small sample sizes.
RESULTS
Damage to vegetation.--Hurricane Gilbert
swept the length of Jamaica. The eye of the
storm passed over all sampled habitats except
for the dry limestone forest at Portland Ridge
(Fig. I), where damage to structure (branches
and trunks) was slight. Among the sites crossed
by the eye of the storm, second-growth lowland
0 30 RIDGE
Fig. 1. Path of Hurricane Gilber over Jamaica on 12 September 1988. Dashed lines indicate approximate
width of hurricane eye, and names indicate approximate locations of sampled habitats: Hardwar Gap, montane
cloud forest, montane pine plantations, and montane coffee; Portland Ridge, dry limestone forest; Discovery
Bay, dry limestone ruinate; Windsor, wet limestone forest and lowland coffee; Negril, lowland secondary
forest, lowland pasture, and mangroves.
habitats with short stature were least damaged
(dry limestone ruinate, Fig. 2A; lowland sec-
ondary forest, Fig. 2E). Structural damage was
most variable in the hilly limestone karst area
around Windsor, where damage to the wet
limestone forest was most severe in the flood-
plain (Fig. 2H), and least severe in a saddle
between two hills (Fig. 2G). Coffee trees were
relatively undamaged compared to the shade
overstory trees in the lowland coffee plantation,
in contrast to the montane open-grown coffee
in which an estimated 60-80% of the coffee trees
were blown over. The most severe structural
damage to large-diameter trees was in man-
groves (Fig. 2F) and montane pine plantations
(Fig. 2J). Thus, topography, tree stature, and
species differences contributed to the variation
in plant structural damage among habitats.
Structural damage accounted for most of the
reduction in foliage in the lowland habitats, as
these habitats had refoliated by the time of our
survey (Figs. 2 and 3). In the lowlands, signif-
icant reductions in the total amount of foliage
were found in only one plot each in lowland
coffee and mangroves (Table 1). Although total
amounts of foliage were unchanged in most
lowland plots, significant changes in the dis-
tribution of foliage indicate that regrowth of
understory foliage compensated for loss of can-
opy foliage in wet limestone forest, lowland
coffee, mangroves, and dry limestone ruinate.
In contrast, we found significant reductions in
the amount of foliage in all plots in montane
cloud forest and montane coffee, and a sugges-
tive (P = 0.07) but statistically nonsignificant
decrease in montane pine plantations (Table 1).
Most of the foliage loss in montane habitats also
was attributed to structural damage, with the
exception of montane cloud forest. The severe
foliage reduction in montane cloud forest (Fig.
3B) was due primarily to the absence of new
foliage as damage to branches and trunks was
moderate (Fig. 2B).
Control sites.--At our two control sites in
Puerto Rico, we detected little change in the
bird populations over a one-year period (No-
vember 1987 to November 1988). For example,
the average number of individuals per point
count did not change significantly in montane
second-growth forest or lowland pasture (Table
2). Only slight decreases were noted in total
numbers of species in each control habitat after
one year, and the species turnover also was low
(Table 2). None of the species in the control
habitats had significant or suggestive popula-
tion changes between censuses.
Species turnover.--On Jamaica, we detected 58
species of birds in the point counts before the
hurricane and 58 species afterwards. Of these,
50 species were encountered before and after,
leaving a turnover of 8 species observed only
before and 8 species observed only after the
hurricane. Species observed only before the
hurricane were infrequent (Crested Quail Dove,
150
A Dry limestone ruinate
(2 plats}
lOO
50,
.D Dry limestone forest (2 plats)
75-
5O
25,
o
15-
lO-
G Wet limestone forest
(1 of 2 plots)
Fig. 2.
E Lowland secondary (2 plots)
--] Undamaged
:[] Branch break
'.[] Trunk lean
Trunk down
I Trunk break
F Mangroves (4 plots)
H Wet limestone forest
(1 of 2 plots)
J Pine (2 plots)
i
DIAMETER CLASSES (CM DBH)
Major structural damage to trees in Jamaica caused by Hurricane Gilbert by diameter class. Trees
classified by most severe damage sustained in following order: trunk break; trunk down (completely uprooted);
trunk lean (partially uprooted); branch breaks (only those > 10-cm diameter); and undamaged. (A) Dry lime-
stone ruinate (Discovery Bay); (B) montane cloud forest (Hardwar Gap); (D) dry limestone forest (Portland
Ridge); (E) lowland secondary forest (Negril); (F) mangroves (Negril); (G-H) wet limestone forest (Windsor);
(J) montane pine plantation (Hardwar Gap). Data pooled for similar 16-m-diameter circle plots; number of
plots noted. Data not pooled in wet limestone forest because of heterogeneity in damage. Number of trees
on Y-axis shows pooled sample sizes of trees in each diameter class.
25-30
20-25
15-20
12-15
10-12 ß ß
8-10
6-8
4-6
3-4
2.5-3
2-2.5
1.5-2
1-1.5
0.5-1
0-0.5
A Dry limestone ruinate
B Montane cloud forest
C Lowland coffee
25-30 D Dry limestone forest
20-25 L
15-2o r
12-15
10-12
8-1o ........
.......... ,,,,.
2.5-3 .......... I
2'2.51
1.5-2 1. ....... ,, ß
1-1.5
0.5-1
0-0.5 ,
E Lowland secondary
F Mangroves
25-30 ;=z=a G Wet limestone forest
20-25 - .............
15-20 ' .................
12-15 ' .................
8-10 '
4-6
3-4
2.5-3 ...... I' fl
2-2.5
0.5-1
0-0.5 ................
Fig. 3.
H Wet limestone forest
ß
[] BEFORE
ß AFTER
0 20 ' 4) 6) ' 8
PERCENT CANOPY COVER
J Pine
i
0 20 40
60 80
Representative foliage-height profiles for various vegetation types throughout Jamaica before and
after Hurricane Gilbert. (A) Dry limestone ruinate (Discovery Bay); (B) montane cloud forest (Hardwar Gap);
(C) lowland coffee (Windsor); (D) dry limestone forest (Portland Ridge); (E) lowland secondary forest (Negril);
(F) mangroves (Negril); (G-H) wet limestone forest (Windsor); (J) montane pine plantation (Hardwar Gap).
For each 16-m-diameter plot shown (except in H), canopy-height profiles recorded along 20 vertical transects
in December 1987 and again in January 1989. Percent cover (X-axis) shown for each height interval in meters
on Y-axis. Height intervals increase with height on (Y-axis).
T^BIE 1. Summary of probability values for tests of similarity in amount and vertical distribution of foliage
before and after Hurricane Gilbert in Jamaica. Changes analyzed by tallying number of increases or decreases
in foliage present in 15 height classes for each plot. Changes in vertical distribution of foliage analyzed
by comparing overall vertical pattern of foliage distribution. Total numbers of vegetation plots shown, but
comparisons of foliage before and after hurricane restricted to matched-plot pairs.
Habitat
Number Foliage amount Foliage
of plots distribution
(before: after) Among all plots a Before vs. after b before vs. after 1/2
Montane cloud forest 4:4
Montane pine plantations 2:2
Montane coffee 2:2
Wet limestone forest 2:2
Lowland coffee 2:2
Lowland secondary forest 2:2
Mangroves 2:4
Dry limestone ruinate 2:2
Dry limestone forest 2:2
<0.001 >0.100
<0.001 0.020 <0.005
0.020 <0.005
<0.001 >0.500
0.068 0.073 <0.005
<0.001 0.004 >0.100
0.004 <0.005
<0.001 0.500 <0.020
0.056 0.254 <0.005
0.054 < 0.005
0.175 0.500 >0.500
0.087 < 0.001 < 0.010
0.508 <0.050
0.552 0.500 <0.005
0.140 0.131 >0.500
0.194 > 0.975
Two-tailed Friedman test.
One-tailed sign test.
Contingency chi-square.
n = 2; Zenaida Dove, n = 1; Red-necked Pigeon,
n = 1; Vetvain Hummingbird, n = 1; White-
eyed Thrush, n = 1; Tennessee Warbler, n = 1;
Hooded Warbler, n = 1; Chestnut-sided War-
bier, n = 6). Most species observed only after
the hurricane were also rare and foraged alone
(Ring-tailed Pigeon, n = 1; Ruddy Quail Dove,
n = 1; Mangrove Cuckoo, n = 3; Greater Antil-
lean Elaenia, n = 1; Cape May Warbler, n = 1;
Yellow-throated Warbler, n = 3), but two spe-
cies were found in flocks (Guiana Parrotlet, n
= 4; European Starling, n = 5). The mean de-
tections per habitat for each bird species are
summarized in Appendix 2.
Species turnover within individual habitats
after the hurricane was frequently high (Table
2). For instance, 12 species were lost from low-
land-coffee and dry-limestone-ruinate habitats.
Fewer were lost in the following habitats: mon-
tane coffee (11 species), montane cloud forest
(10 species), and montane pine plantation (10
species). On average, the loss of species from a
habitat was greater than the addition of new
species to the same habitat following the hur-
ricane, though this difference was only sugges-
tive (paired t-test, t = 1.95, P = 0.08; Table 2).
The average number of species per habitat also
showed a suggestive, but not significant, de-
cline (paired t-test, t = 1.95, P < 0.08; Table 2).
The average number of habitats occupied by a
species declined significantly (paired t-test, t =
2.41, P = 0.02) from 3.7 + 0.4 habitats per species
before the hurricane to 3.2 + 0.4 habitats per
species afterward. Despite the high spatial vari-
ation in damage within some habitats, the vari-
ance in individuals detected per point count
was generally similar in the pre- and posthur-
ricane counts. Only in the montane pine plan-
tations were significant differences (Fmax = 3.13,
P < 0.01) found in the variance of individuals
detected per point count before (9.4) and after
(3.0) the hurricane.
Abundance.--The mean number of individu-
als detected per point count changed signifi-
cantly after the storm's passage in 5 of the 10
habitats (Table 2). We found significantly fewer
individuals per point count in the three mon-
tane habitats--cloud forest, pine, and coffee
plantations. Netting results in montane cloud
forest and montane coffee were consistent with
the point counts as indicated by dramatic de-
clines in total captures. The projected capture
rates, consequently, were low within the two
habitats (Table 3). In contrast, we detected sig-
TABLE 2. Changes in mean number of individuals, total number of species, and species turnover in fixed-
radius point counts in 2 habitats in Puerto Rico (Controls) and 10 habitats in Jamaica before and after
Hurricane Gilbert. Comparison of mean values before and after hurricane for each habitat made with a
Mann-Whitney U-test. Paired t-test used to determine significance level for total means.
Individuals per point count
(œ + SE) Total no. species Before After
Habitat Before After Before After only only
Species turnover
Controls (Puerto Rico)
Montane second-growth forest 5.6 + 0.3 6.1 + 0.4 21 18 4 1
Lowland pasture 4.8 + 0.4 4.7 _+ 0.3 18 17 5 4
Treatments (Jamaica)
Montane cloud forest 3.3 _+ 0.3 2.3 _+ 0.4 b 27 21 10 4
Montane pine plantation 5.0 + 0.6 2.1 _+ 0.3 a 23 19 9 5
Montane coffee 2.9 +- 0.3 1.5 _+ 0.3 a 18 9 11 2
Wet limestone forest 3.8 _+ 0.6 5.0 + 0.6 c 28 32 3 7
Lowland coffee 3.0 _+ 0.4 2.5 _+ 0.6 26 20 12 6
Lowland secondary forest 4.8 + 0.5 4.8 _+ 0.4 27 29 7 9
Mangroves 4.4 _+ 0.3 5.5 + 0.4 c 22 23 5 6
Lowland pasture 4.5 _+ 0.6 4.3 _+ 0.6 25 23 7 5
Dry limestone ruinate 3.7 _+ 0.4 3.4 + 0.5 24 20 12 8
Dry limestone forest 3.0 +_ 0.4 3.5 _+ 0.4 21 20 4 3
Mean total 3.7 3.4 24.1 21.6 a 8.0 5.5 a
SE 0.3 0.4 1.0 1.9 1.0 0.7
P - 0.001. b p - 0.003. P = 0.05. d p = 0.08.
nificantly more individuals per point count in
the wet limestone forest and mangroves. Net-
ting results supported the point-count results
in the wet limestone forest, but not in the man-
groves. This inconsistency in the mangrove re-
suits may occur because the 1987 netting was
initiated in the late afternoon and the 1989 net-
ting was initiated in the early morning. The
mist-net and point-count results were consis-
tent in lowland secondary forest and dry lime-
stone forest, where we found no significant
changes.
When making a large number of statistical
comparisons, some observations are expected to
deviate significantly from expected values by
chance alone. For example, we performed 211
individual tests for population changes after the
hurricane, of which 10% (21.1) and 5% (10.6)
were expected to differ by chance at significance
levels of 0.10 and 0.05, respectively. However,
we found that 56 populations changed at P -<
0.10 and that 37 populations changed at P -<
0.05 (Table 4). Furthermore, eight populations
showed changes at the level of 0.001--a very
unlikely random event. We conclude that the
majority of the population changes after the
hurricane were not artifacts of the large number
of statistical comparisons.
Eighteen species showed significant or sug-
gestive declines in mean number of individuals
per point count in one or more habitats (Table
4). These declines could result from either hur-
ricane-induced mortality, movement to other
habitats, or decreased detectability. Sixteen spe-
cies showed significant or suggestive increases
in mean number of individuals per point count
in one or more habitats (Table 4). These increas-
es could result from movement into a habitat,
because the birds were easier to detect as a result
of increased foraging activity, or because pre-
viously obscured canopy dwellers became more
apparent. Eight species decreased in some hab-
itats and increased in other habitats (Table 4).
Such observations are consistent with a be-
tween-habitat migration, but factors such as
changes in detectability could also be involved.
To examine changes in detectability, we used
the methods of Hutto et al. (1986) to calculate
detectability ratios for each species both before
and after the hurricane. The ratio is equivalent
to the number of point counts at which a given
species was recorded only beyond the 25-m ra-
dius, divided by the total number of counts at
which the species was recorded. Of 48 species
with adequate sample sizes before and after the
storm, 23 species were more detectable after the
storm, 17 species were less detectable, and 8
species were unchanged. The number of species
TABLE 3. Summary of mist-net capture results before and after Hurricane Gilbert in six Jamaican habitats.
Slope and Y-intercept derived from regression of captures per net hour against net hours.
Total
Individuals !
Habitat Net hours Species Captures 100 net h Slope Y-intercept
Montane cloud forest
Before 195.5 23 130 66.5 -0.001 0.79
After 293.7 16 54 !8.4 -0.00! 0.34
Montane coffee
Before 176.9 18 74 41.8 - 0.002 0.59
After 200 10 32 16.0 -0.001 0.24
Wet limestone forest
Before 170.5 17 56 32.8 -0.002 0.50
After 178.0 27 89 50.0 - 0.004 0.91
Lowland secondary forest
Before 192.5 21 79 41.0 -0.005 0.91
After 148.5 23 80 53.8 -0.004 0.98
Mangroves
Before 121.0 20 122 100.8 -0.019 2.67
After 172.6 25 151 87.5 +0.002 0.86
Dry limestone forest
Before 283.8 16 46 16.2 - 0.00! 0.32
After 140.0 17 39 27.9 -0.001 0.37
that were more detectable was not significantly
different from the number of species that were
less detectable (chi-square goodness-of-fit test,
X 2 = 0.90, df = 1, P < 0.50).
Four species were significantly (P < 0.05) more
detectable after the hurricane--Streamertail,
Greater Antillean Bullfinch, Yellow Warbler,
and Arrow-headed Warbler. The Olive-throat-
ed Parakeet and Jamaican White-eyed Vireo
were significantly less detectable. However, no
obvious relationship was found between
changes in a species' detectability ratio and
changes in the average number of individuals
per point count after the hurricane. Thus, sig-
nificant changes in detectability ratios were
found in some species after the hurricane, but
it is unlikely that these changes caused a con-
sistent bias.
Overall patterns.--We found a strongly sug-
gestive (G = 16.64, df = 9, P = 0.055) three-way
interaction of habitat, diet, and population trend
based on the log-linear analysis. Tests for con-
ditional independence were run on two factors
at a time given the level of a third factor. For
instance, a significant interaction was found be-
tween diet and population trend for specific
habitats (G = 21.18, df = 10, P = 0.02). A sig-
nificant interaction was found between habitat
and population trend for a given diet type (G
= 35.39, df = 18, P = 0.008). There was no sig-
nificant interaction between habitat and diet for
a given population trend (G = 20.86, df = 18, P
= 0.34). However, a test of independence in-
dicated a significant (G = 42.68, df = 27, P <
0.05) interaction between diet and population
trend.
Previous hurricane studies have suggested
that montane bird populations are affected more
than lowland populations (J. Wiley, unpubl.
manuscript). To test this possibility, we com-
pared the trends (i.e. decrease versus increase/
no change) of each species' population in each
montane habitat (habitats above 700 m; n = 3)
with the trends of populations in the lowland
habitats (n = 7). This comparison indicated a
significant difference (G = 4.45, df = 1, P = 0.04)
in which 63% (49 of 78) of the montane popu-
lations declined compared to 48% (100 of 210)
of the lowland populations. As noted previ-
ously, this pattern was also evident in the av-
erage number of individuals per point count
(Table 2).
We expected the pattern of population de-
cline in the montane regions to vary with diet,
with those species relying directly on plants for
food suffering most (J. Wiley, unpubl. manu-
script). To examine this possibility, we catego-
rized species into four diet categories (nectari-
TABLE 4. Species that declined or increased (P -< 0.10) in mean detections per point count after passage of
Hurricane Gilbert in Jamaica. Habitats where declines or increases detected are listed, as are significance
levels based on comparison of pre- and posthurricane point counts using Mann-Whitney U-test.
Location of decline (P) Location of increase (P)
Dry limestone forest (0.063)
Montane cloud forest (0.001)
Montane coffee (0.006)
Montane pine plantation (0.001)
Lowland secondary forest (0.10)
Lowland coffee (0.08)
Caribbean Dove
Streamertail
Loggerhead Kingbird
Black-faced Grassquit
Montane cloud forest (0.03)
Montane coffee (0.001)
Montane pine plantation (0.013)
Yellow-shouldered Grassquit
Dry limestone ruinate (0.04)
Gray Catbird
Lowland secondary forest (0.086)
Black-throated Blue Warbler
Montane coffee (0.03)
Wet limestone forest (0.08)
Lowland coffee (0.08)
Dry limestone forest (0.08)
Montane pine plantation (0.02)
Lowland coffee (0.04)
Lowland coffee (0.08)
Ovenbird
Black-and-white Warbler
Chestnut-sided Warbler
Bananaquit
Orangequit
Stripe-headed Tanager
Montane pine plantation (0.001)
Montane coffee (0.04)
Lowland pasture (0.05)
Montane pine plantation (0.001)
Montane coffee (0.04)
Montane cloud forest (0.10)
Montane coffee (0.04)
Lowland secondary forest (0.09)
Montane coffee (0.04)
Lowland secondary forest (0.02)
Montane pine plantation (0.09)
Montane cloud forest (0.07)
Montane pine plantation (0.08)
Wet limestone forest (0.001)
Lowland coffee (0.020)
Dry limestone forest (0.018)
Wet limestone forest (0.09)
Lowland coffee (0.02)
Dry limestone forest (0.018)
Greater Antillean Bullfinch
Montane pine plantation (0.09)
White-chinned Thrush
Lowland coffee (0.04)
Blue Mountain Vireo
Jamaican Oriole
Montane cloud forest (0.06)
Dry limestone ruinate (0.04)
T^BI,œ 4. Continued.
Location of decline (P) Location of increase (P)
Lowland coffee (0.02)
Lowland pasture (0.006)
Dry limestone ruinate (0.04)
PrairieWarbler
Montane cloud forest (0.09)
Mangroves (0.003)
Jamaican Woodpecker
Mangrove Cuckoo
Dusky-capped Flycatcher
Jamaican Euphonia
Dry limestone forest (0.05)
Mangroves (0.08)
Wet limestone forest (0.09)
Lowland secondary forest (0.001)
Dry limestone ruinate (0.08)
Dry limestone forest (0.04)
Lowland secondary forest (0.05)
Jamaican White-eyed Vireo
Dry limestone forest (0.03)
Yellow Warbler
Northern Parula
Yellow-faced Grassquit
Mangroves (0.001)
Lowland pasture (0.08)
Dry limestone ruinate (0.04)
vore, fruit/seedeater, resident insectivore,
migrant insectivore), and the number of pop-
ulations that decreased was compared to those
that either increased or showed no change. We
found a significant interaction between diet type
and population trend in montane habitats (G =
10.69, df = 1, P = 0.01), indicating that nectar-
ivores and fruit/seedeaters were more likely to
have declining populations than insectivores in
montane habitats. For instance, declines in
montane habitats occurred in 80% of the nec-
tarivore populations (n = 10), 83% of the fruit/
seedeater populations (n = 23), 50% of the res-
ident insectivore populations (n = 22), and 44%
of the migrant insectivore populations (n = 23).
Even with the exclusion of nonnative montane
habitats (pine and coffee), the pattern of pop-
ulation decline and diet remained. For example,
in montane cloud forest 67% of the nectarivore
populations (n = 3), 90% of the fruit/seedeater
populations (n = 10), 50% of the resident in-
sectivore populations (n = 10), and 29% of the
migrant insectivore populations (n = 7) de-
clined.
Population decline in these montane habitats
may be related to foraging height within the
habitat. Therefore, we used the observations of
Lack (1976) to classify the montane species into
those confined to the forest understory and those
that are primarily canopy dwellers. It was dif-
ficult to find canopy-only species, because many
canopy dwellers frequently descend to the un-
derstory via gaps and edges (e.g. Wunderle et
al. 1987). Our analysis of population trends based
on foraging location indicated that 60% of mon-
tane populations confined to the understory (n
= 20) had declining population trends. The re-
maining 40% had trends indicating increase or
no change. The same pattern (i.e. 60% declin-
ing, 40% increase/no change) was also found
for canopy dwellers (n = 58), suggesting that
the pattern of population decline in montane
habitats was unrelated to foraging height.
We examined the possibility that the ob-
served increases in the number of individuals
in two lowland habitats (wet limestone forest
and mangroves) after the hurricane might be
attributed to an influx of montane nectarivores
and fruit/seedeaters. The number of lowland
populations that changed (decrease/no change
versus increase only) was tallied for species in
different diet categories. Fifty percent of the
lowland nectarivore populations increased, 54%
of the fruit/seedeater populations increased, and
both the resident (67%) and migrant (47%) in-
sectivores increased. No significant interaction
occurred between diet type and population
trend in the two lowland habitats (G = 0.13, df
= 3, P = 0.99). Thus, nectarivores and fruit/
seedeaters were not any more likely than in-
sectivores to have increasing populations after
the hurricane in the two lowland habitats.
Increases in bird populations in the two low-
land habitats after the hurricane might also be
attributed to increased detectability of canopy
species that were foraging at ground level. We
found that 62% of the canopy/understory pop-
ulations (n = 47) had increased in contrast to
38% of the understory populations (n = 16).
Although this trend was suggestive, it was not
possible to test statistically because of the con-
founding effect of diet on foraging location. For
instance, 56% of the species relying upon plants
for food (n = 27) were canopy species, in con-
trast to 80% of the insectivores (n = 40), a sig-
nificant difference (G = 4.50, df = 1, P < 0.05).
DISCUSSION
Altitude and diet.--The hurricane's impact on
bird populations was much less severe in low-
land habitats than in the montane habitats. Al-
though the storm's intensity was probably
greatest in the uplands, damage to trunks and
branches of trees in some lowland habitats (e.g.
mangroves and wet limestone forest) was ac-
tually greater than in the montane cloud forest.
Furthermore, many of the lowland habitats (wet
limestone forest, lowland secondary forest,
mangroves, lowland pasture, dry limestone ru-
inate) reportedly had been extensively defoli-
ated (including loss of flowers and fruit). How-
ever, a major difference between lowland and
montane vegetation was the rapidity with which
the vegetation recovered. For example, most of
the lowland sites had reportedly refoliated
within several weeks, yet montane trees were
still defoliated and showed the greatest differ-
ences between pre- and posthurricane canopy
profiles four months later. Even after 10 months,
many of the trees at high altitude were just
beginning to produce new leaves (Varty 1991).
Slower recovery of montane vegetation also was
reported in Puerto Rico after hurricanes San
Felipe (Bates 1930) and Hugo (pers. observ.),
and in Dominica following Hurricane David
(Lugo et al. 1983). Slow rates of recovery from
disturbance may be typical of montane cloud
forests (Weaver 1986).
Our findings that population declines in
montane habitats were related to diet suggest
that the greatest impact of Hurricane Gilbert on
Jamaica's montane bird populations was from
indirect effects that occurred after its passage,
rather than from direct exposure to the storm.
It seems unlikely that resident insectivores in
the mountains were somehow less vulnerable
to the hurricane's high winds and rains than
most fruit / seedeaters and nectarivores residing
in the same place. It is possible that humming-
birds, because of their small mass and high met-
abolic rate, suffered considerable mortality from
exposure to the hurricane. Indeed, Streamer-
tails (6 g) decreased significantly in more hab-
itats (n = 4) than any other species, but the
larger nectarivorous Bananaquits (11 g) and Or-
angequits (16 g) also declined significantly in
some habitats. Moreover, the small (6.4-g) in-
sectivorous Jamaican Tody showed no popula-
tion changes after the storm, despite its pre-
hurricane abundance. These findings are more
consistent with a posthurricane-food-stress ex-
planation than with the possibility of differ-
ential mortality arising from different vulner-
abilities to hurricane exposure. Furthermore,
most migrants were probably absent when Gil-
bert struck on 12 September (Lack and Lack
1972), yet both resident and migrant insecti-
vores displayed similar population declines (50%
and 44%, respectively). This also indicates that
the indirect effects of Gilbert on terrestrial birds
were greater than the direct impact of the storm.
Gilbert's most important direct effect apparent-
ly was on the vegetation, which affected bird
populations secondarily by limiting food after
the storm's passage.
In the montane region the degree of damage
inflicted by the hurricane on bird populations
varied among the different food-resource types.
The winds which defoliated most habitats un-
doubtedly also stripped flowers and fruits from
plants, as reported in other hurricanes (Bates
1930; N. F. R. Snyder and H. A. Snyder, unpubl.
1979 report; Wunderle, unpubl. data). Indeed,
flower and fruit abundance still appeared low
in the montane sites at the time of our surveys,
four months after the hurricane. Arthropod
populations were probably reduced by the
storm, but because of their shorter life cycles
and rapid reproductive rates, they may have
recovered more quickly than the vegetation. In
addition, portions of some insect populations
(e.g. Diptera, Lepidoptera, Coleoptera) likely
survived the storm as larvae or pupae in rela-
tively protected sites in the soil, in leaf litter,
and under bark (Wolcott 1932; B. Freeman, pers.
comm.). Also, some insect populations might
increase after the storm due to decreased pre-
dation and increases in their resources (J. Tor-
res, pers. comm.). Thus, a reliance on a food
source with a high diversity and turnover rate
(i.e. arthropods) could buffer montane insectiv-
orous birds from hurricane-induced food short-
ages.
The decline in montane nectarivores and
fruit/seedeaters could have resulted from
movement out of the montane habitats into oth-
er less damaged sites. As foragers on patchily
distributed and temporarily available food re-
sources, tropical nectarivores and frugivores
range widely and often migrate seasonally and
altitudinally in some tropical regions (e.g. Stiles
1983). Tropical insectivores, which feed on more
predictable resources, tend to wander less than
nectarivores, frugivores and seedeaters. For in-
stance, under drought conditions in the Carib-
bean, insectivorous birds tend to have the most
stable populations while nectarivores and fruit/
seedeaters are most likely to decline (Faaborg
et al. 1984). Presumably, some of these declines
result from migration or nomadism. The reli-
ance on widely distributed and temporary food
resources could preadapt nectarivores and fruit/
seedeaters to respond to localized hurricane-
induced food shortages through emigration.
Despite potentially higher levels of flowering
and fruiting in the lowlands, there was no de-
tectable overall influx of montane nectarivores
and fruit/seedeaters into the lowlands. Our in-
ability to detect an increase in these foraging
types in the lowlands may have resulted from
surveys in the wrong lowland habitats or lo-
cations, or the inability of point counts to ac-
curately detect relatively small increases (5-
10%). The montane sites were in east-central
Jamaica, whereas most of the lowland sites were
in western Jamaica. Furthermore, montane hab-
itats above 1,000 m elevation comprise only 4-
6% of the total land area in Jamaica, and it would
be difficult to detect an influx from the rela-
tively small montane populations into such an
extensive lowland area. However, some species
decreased in some habitats and increased in oth-
ers. This implies localized movements, where
birds moved from a damaged to a less-damaged
site. For example, the Bananaquits probably em-
igrated from montane habitats (significant de-
clines in two habitats) and into lowland habitats
(significant increases in three habitats). Bana-
naquits feed on nectar from a high diversity of
flowers (Snow and Snow 1971, Lack 1976) and
may be very sensitive to flower abundance, as
evidenced by drastic declines in dry forest un-
der drought conditions (Faaborg et al. 1984).
The White-chinned Thrush, a widespread fru-
givore, also fit a pattern consistent with inter-
habitat movement. They disappeared from
montane coffee and lowland secondary forest,
and increased in lowland coffee. Local inter-
habitat movements within the lowlands also
occurred. For example, the Prairie Warbler, an
overwintering migrant insectivore, decreased
significantly in three lowland habitats and in-
creased markedly in mangroves. Prairie War-
biers appeared after the hurricane in the middle
of the defoliated montane cloud forest, a habitat
in which they had not been encountered pre-
viously. Several other species had posthurri-
cane population shifts consistent with an in-
terhabitat movement pattern, though the
differences were not as marked.
Foraging substrates and cover.--Whereas post-
hurricane food loss explains most observed
population declines, factors such as changes in
foliage profiles and vegetation structure could
affect certain species. For example, loss of high-
canopy foraging substrates undoubtedly ex-
plains the absence of Black-and-white Warblers
from montane pine plantations and their de-
cline in lowland coffee plantations. The over-
story trees in both of these habitats suffered
substantial loss of branches and twigs, where
this migrant warbler normally gleans insects.
Extensive damage to mimosaceous trees in the
overstory of lowland coffee, lowland pasture,
and dry limestone ruinate scrub probably con-
tributed to the decline of overwintering mi-
grant Prairie Warblers, which commonly glean
insects from their leaves (Lack and Lack 1972).
Many forest-floor species are accustomed to for-
aging in a dark forest understory and are likely
to leave areas with reduced canopy cover. Such
a response was suggested by the declining post-
hurricane Ovenbird populations in wet lime-
stone and lowland coffee. Ovenbirds are insec-
tivorous migrants that normally feed on the
forest floor only where a canopy is found over-
head (Lack and Lack 1972). Thus, structural
damage to vegetation produced by hurricanes
could eliminate foraging substrates, as well as
the vegetation characteristics used by some spe-
cies as proximal cues for habitat selection.
Hurricane-induced changes in foliage distri-
butions could also disrupt the stratification of
foraging normally associated with different fo-
liage layers (e.g. MacArthur et al. 1966). This
disruption should be most apparent in forests
of tall stature in which prehurricane separation
of canopy and understory foraging zones was
most distinct. Such was the case in the aftermath
of Hurricane Hugo in Puerto Rico, where can-
opy destruction caused many former canopy
dwellers to forage at ground level (Wunderle
unpubl. data). Increased numbers of individu-
als in Jamaican mangroves and wet limestone
forest may have resulted from displacement of
canopy dwellers, although we were unable to
test this hypothesis statistically. Furthermore,
frequent hurricanes may, over the long term,
make it difficult for Caribbean forest-dwelling
species to segregate on the basis of foraging
height (J. Faaborg, pers. comm.). This may ac-
count for the findings of MacArthur et al. (1966),
in which Puerto Rican species appeared to rec-
ognize two vertical layers in the forest while
those in Panama recognized four layers.
The tremendous loss of overstory canopy and
the overall reduction of foliage in some patches
of mangroves may account for the apparent
posthurricane increase in Yellow Warblers. Al-
though this resident warbler will sometimes
forage in dry scrub bordering mangroves, we
found them only in mangroves. Yellow War-
biers have one of the narrowest habitat breadths
of any Jamaican species (Lack 1976), and their
"reluctance" to use other habitats may have
compressed their populations into the remain-
ing mangrove fragments. Density increases in
remnant mangrove fragments also could ex-
plain the increased number of aggressive in-
teractions and vocalizations detected after the
hurricane. Thus, some species with narrow hab-
itat preferences may respond to hurricane dam-
aged habitats by remaining at higher densities
in remnants of their original habitat rather than
by moving into other nearby habitats. The con-
sequences of remaining in fragments of original
habitat, at higher than normal densities, as op-
posed to moving into other habitat types are
unknown. However, in the case of Yellow War-
biers, the high primary productivity of man-
groves (Lugo and Snedaker 1974) may have al-
lowed a rapid recovery of insects, their primary
food source. This may have allowed the war-
biers to remain in their traditional habitat de-
spite substantial vegetation damage.
Some characteristics of Caribbean birdlife.--It is
reasonable to expect that species restricted to a
single habitat type are most at risk of extinction
from habitat damage by hurricanes. Our results
indicate that this is even more likely for nec-
tarivores and fruit/seedeaters restricted to high
montane forests, particularly when undamaged
lowland habitats are unavailable. This could oc-
cur on mountainous islands with a limited
coastal plain, or on islands in which lowland
vegetation has been destroyed for agriculture.
This was the situation on St. Kitts, where all
but the mountain summit was planted in sugar
cane in the late 19th century (Beard 1949). The
Puerto Rican Bullfinch (Loxigilla portorecensis
grandis), a fruit/seedeater, was abundant on that
island in the late 1800s, but it was confined to
high-elevation forest on one mountain. In 1899,
two hurricanes hit the island and may have
reduced the bullfinch population to a level from
which it could not recover (Raffaele 1977). After
the hurricanes, the bullfinches were probably
unable to find food in the sugar-cane dominated
lowlands and, as our study suggests, it is likely
that the montane fruit and seed crops were de-
stroyed. Although the population persisted un-
til at least 1929 (Olson 1984), it is likely that it
was no longer viable. Thus, in this instance, a
combination of hurricane destruction of a food
resource in an area with slow recovery and an
absence of alternative habitats or food sources
may have contributed to extinction of a bird
species. Perhaps montane nectarivores and fruit/
seedeaters in the Caribbean face higher risks of
hurricane-induced extinctions, particularly as
more lowland forests are destroyed for agri-
culture.
If the slower recovery of hurricane-damaged
montane vegetation places stress on montane
bird populations for longer periods than low-
land populations, then hurricanes may contrib-
ute to some of the commonly observed patterns
of avian distribution in the Caribbean. For ex-
ample, throughout the Caribbean, montane for-
ests support fewer bird species than lowland
forests (e.g. Kepler and Kepler 1970, Ricklefs
and Cox 1972, Lack 1976). Also, more endemic
species are found in montane forests than in
the lowland forests of the Caribbean (Ricklefs
and Cox 1972, Lack 1976). Hurricane-related ex-
tinctions of one or several disjunct montane
populations may contribute to endemism among
montane species. In addition, island birds tend
to use a wider range of habitats than continental
species (e.g. Crowell 1962, MacArthur et aL
1966), and this trait appears to favor posthur-
ricane survival. Thus, hurricanes could contrib-
ute to these avifaunal characteristics on Carib-
bean islands by reducing the number of species
surviving in montane habitats, increasing en-
demism and extinction rates of montane spe-
cies, and favoring the survival of species ca-
pable of using a broad range of habitats.
ACKNOWLEDGMENTS
Ariel Diaz Perez and Luis E. Migenis Lopez pro-
vided excellent field assistance and suffered a variety
of indignities with good humor. Marcel Anderson
and Elaine Foster of the Natural Resource Conser-
vation Division (Ministry of Agriculture) and Roy
Jones of the Department of Forestry kindly provided
permits and assistance. Erroil Ziadie and R. Campbell
provided assistance and permission to work on their
land. Advice was provided by Alexander Cruz, Au-
drey Downer, Brian Freeman, Richard Holmes, Chan-
dler Robbins, Robert Ross, Ann Haynes-Sutton, Rob-
ert Sutton, and Jeremey Woodley, and members of
the Gosse Bird Club. The manuscript benefited from
the comments of Robert Askins, John Faaborg,
James Lynch, Fred Scatena, Noel Snyder, Juan Torres,
Peter Weaver, James Wiley, Michael Willig, and Glen
Woolfenden. Financial support was provided by the
World Wildlife Fund-U.S., University of Puerto Rico,
and the National Science Foundation (BSR-8811902)
through the Luquillo Long-term Ecological Research
program.
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APPENDIX 1. Site descriptions. All sites have been
described previously in detail (Lack 1976, Kapos
1986, Proctor 1986, Tanner 1986, Anonymous 1987).
Montaae cloud forest.--Very Wet Ridge Forest (Tanner I983) on Mr.
Horeb and Mr. Oatley in Port Royal Mountains (I,350 m elevation;
mean annual rainfall 1,900 mm). Nets set along Shelter Trail in Hardwar
Gap Forest Reserve, and vegetation measured in two plots near Shelter
Trail and two near Mr. Horeb Trail. Overstory (up to 20 m tall) dom-
inated by Cyrilla racemifiora, Podocarpus urbanii, Hedyosemum arborescens,
Mecranium purpurascens, Clethra occidentalis, Alchornea latifolia, and Den
dropanax pendulus, with tree ferns (Cyathea spp.) understory.
Montane coffee.--Shadeless coffee (3-4 m height) with an understory
of grasses and forbs on Mr. Horeb near Hardwar Gap (ca. 1,300 m) in
Port Royal Mountains.
Montane pine plantations.--Small plantations sampled between Har-
dwar Gap and Irish Town on south side of Port Royal Mountains (ca.
1,000-1,300 m elevation; mean annual rainfall 1,900 mm). Even-aged
Pinus caribaea plantations (canopy 12-25 m) had a few Eucalyptus, with
an understory of ginger, bamboo, and ferns, as sampled in vegetation
plots at Woodside Estate in Greenwich.
Wet limestone forest.--Forest sampled at Windsor (ca. 300-600 m ele-
vation; mean annual rainfall 2,000-2,500 mm) in limestone karst region
known as Cockpit Country. Vegetation plots located near mist nets in
floodplain forest (property of Mr. Campbell), and in saddle next to
Windsor Cave. Canopy height reached 15-20 m in uplands and 25-35
m in lowlands. Cockpit Country has list of 46 tree species, including
many in the Sapotaceae and Lauraceae with prominent endemics such
as Terrainalia arbuscula and Manilkara excisa.
Lowland coffee.--Small plantations with a shade overstory (Mimosa-
ceae; 15-20 m canopy) and coffee understory (2-3 m) at Windsor.
Lowland secondary forest.--Mist netted and sampled vegetation at site
APPENDIX 1, Continued.
near Negril Cabins in Negril (<10 m elevation; mean annual rainfall
1,900-2,540 mm); point counts made here and to north along main road.
Canopy heights of 6-I0 m for dominant Pithecellobium sp. in these
disturbed second-growth forests.
Mangroves.--Nets and two vegetation plots located in mangroves near
Negril Municipal dump, and two additional vegetation plots in Green
Island. Point counts made in both areas. Overstory (canopy 12-15 m)
dominated by Avicennia nitida and Rhizophora mangle, while Hibiscus
tiliaceus and coconut palms common on higher ground.
Lowland pasture.--Point counts made in pastures east of Green Island
(near sea level), but no vegetation or mist-net samples obtained. Pasture
contained scattered large leguminous trees (Pithecellobium sp. and Hae-
matoxylum sp.). Diversity of large (10-I5 m tall) leguminous trees in
fence rows bordering pastures.
Dry limestone ruinate.--Censuses taken at Discovery Bay (10-30 m
elevation; mean annual rainfall 1,000-I,500 mm). Censuses and vege-
tation plots located south of Columbus Park and at University of the
West Indies Marine Biology Station. Dry scrub vegetation disturbed by
cutting (canopy 6-10 m). Common tree species include Bursera simaruba,
Metopium brownil, Fagara spinosa, Coccoloba sp., and Tabebuia sp.; a colum-
nar cactus (Stenocereus hystrix) also common.
Dry limestone forest.--Relatively undisturbed dry forest sampled at
Portland Ridge (100-150 m elevation; mean annual rainfall 1,270-1,900
ram). Mist nets and vegetation plots located in well-developed forest
(canopy 10-16 m), but canopy height lower in many of point-count
areas on ridges. Flora similar but more diverse than at Discovery Bay.
Largest trees (up to 80 cm dbh) were Bursera sirearuba, while Tecoma
stans, Thrinax parvifiora, and Bauhinia divaricata present in understory.
APPENDIX 2. Mean number of individuals per point count before (upper row) and after (lower row) Hurricane
Gilbert for 10 habitats in Jamaica. Acronyms for habitats and number of point counts in each as follows:
MCF, montane cloud forest (n = 43); MPP, montane pine plantations (n = 30); MC, montane coffee (n =
33); WLF, wet limestone forest (n = 30); LC, lowland coffee (n = 28); LSF, lowland secondary forest (n =
30); Ma, mangroves (n = 30); LPa, lowland pasture (n = 30); DLR, dry limestone ruinate (n = 30); DLF, dry
limestone forest (n = 30). Letters for diet indicate: F, fruit or seed; N, nectar; I, insects. Significance level
for before-and-after comparisons indicated by footnotes.
Habitats
Species Diet MCF MPP MC WLF LC LSF Ma LPa DLR DLF
White-crowned Pigeon F 0.00 0.00 0.00 0.00 0.04 0.00 0.07 0.00 0.00 0.00
(Columba leucocephala) 0.00 0.00 0.00 0.00 0.00 0.00 0.07 0.00 0.00 0.00
Red-necked Pigeon F 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.00
(C. squamosa) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Ring-tailed Pigeon F 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
(C. caribaea) 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.00 0.00
Zenaida Dove F 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00
(Zenaida aurita) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
White-winged Dove F 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.07 0.00
(Z. asiatica) 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00
Common Ground Dove F 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.10 0.03 0.00
(Columbina passerina) 0.00 0.00 0.00 0.00 0.14 0.07 0.03 0.10 0.00 0.00
Caribbean Dove F 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.37
(Leptotila jamaicensis) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.07 b
Ruddy Quail Dove F 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
(Geotrygon montana) 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.00
Crested Quail Dove F 0.02 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.00 0.00
(G. versicolor) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Olive-throated Patakeel F 0.00 0.00 0.00 0.30 0.00 0.07 0.07 0.13 0.30 0.00
(Aratinga nana) 0.00 0.00 0.00 0.33 0.07 0.20 0.10 0.10 0.00 0.00
APPENDIX 2. Continued.
Species Diet MCF MPP
Habitats
MC WLF LC LSF Ma LPa DLR DLF
Guiana Parrotlet F 0.00 0.00 0.00
(Forpus passerinus) 0.00 0.00 0.00
Mangrove Cuckoo I 0.00 0.00 0,00
(Coccyzus minor) 0.00 0.00 000
Chestnut-bellied Cuckoo I 0.02 0.00 0.00
(Hyetornis pluvialis) 0.00 0.00 0.00
Jamaican Lizard Cuckoo I 0.00 0.00 0.00
(Saurothera vetula) 0.00 0.00 0.00
Smooth-billed Ani I 0.00 0.00 0.00
(Crotophaga ani) 0.00 0.00 0.00
Jamaican Mango N 0.00 0.00 0.03
(Anthracothorax mango) 0.00 0.00 0.00
Streamertail N 0.77 0.67 0.24
(Trochilus polytmus) 0.15 f 0.17 0.00 a
Vervain Hummingbird N 0.00 0.00 0.00
(Mellisuga minima) 0.00 0.00 0.00
Jamaican Tody I 0.09 0.03 0.06
(Todus todus) 0.11 0.10 0.09
Jamaican Woodpecker I 0.02 0.03 0.00
(Melanerpes radiolatus) 0.00 0.00 0.00
Jamaican Becard I 0.00 0.00 0.00
(Platypsaris niger) 0.00 0.00 0.00
Loggerhead Kingbird I 0.00 0.07 0.03
(Tyrannus caudifasciatus) 0.02 0.00 0.03
Stolid Flycatcher I 0.00 0.00 0.00
(Myiarchus stolidus) 0.00 0.00 0.00
Dusky-capped Flycatcher I 0.02 0.03 0.00
(M, barbirostris) 0,02 0.03 0.00
Rufous-tailed Flycatcher I 0.00 0.00 0.00
(M. validus) 0.00 0.03 0.00
Greater Antillean Pewee I 0.02 0.07 0.00
(Contopus caribaeus) 0.00 0.03 0.00
Greater Antillean Elaenia I 0.00 0.00 0.00
(Elaenia fallax) 0.02 0.00 0.00
Yellow-crowned Elaenia I 0.00 0.00 0.00
(Myiopagis cotta) 0.00 0.00 0.00
Gray Catbird F 0.00 0.00 0.00
(Dumatella carolinensis) 0.00 0.00 0.00
Northern Mockingbird F 0.00 0.00 0.03
(Mimus polyglottos) 0.00 0.00 0.00
Rufous-throated Solitaire F 0.02 0.07 0.00
(Myadestes genibarbis) 0.00 0.00 0.00
White-chinned Thrush F 0.07 0.00 0.12
(Turdus aurantius) 0.09 0.03 0.00
White-eyed Thrush F 0.02 0.00 0.00
(T. jamaicensis) 0.00 0.00 0.00
Yellow-faced Grassquit F 0.02 0.00 0,00
(Tiaris olivacea) 0.00 0.00 0.00
Black-faced Grassquit F 0.26 0.47 0.70
(T. bicolor) 0.04 0.10 c 0.18
Yellow-shouldered Grassquit F 0.00 0.00 0.00
(Loxipasser anoxanthus) 0.00 0.00 0.00
Greater Antillean Bullfinch F 0.16 0.03 0.12
(Loxigilla violacea) 0.07 0.20 b 0.00 c
Stripe-headed Tanager F 0.51 0.30 0.03
(Spindalis zena) 0.30 b 0.07 0.00
Jamaican Euphonia F 0.02 0.03 0.00
(Euphonia jamaica) 0.02 0.00 0.00
Orangequit N 0.26 1.00 0.18
(Euneornis campestris) 0.21 0.03 f 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.13 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.10 b 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.03 0.00 0.00 0.00 0.00 0.00 0.00
0.67 0.00 0.00 0.00 0.00 0.00 0.00
0.67 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.04 0.03 0.00 0.43 0.00 0.00
0.00 0.07 0.00 0.03 0.43 0.00 0.00
0.00 0.00 0.00 0.03 0.00 0.03 0.27
0.00 0.00 0.00 0.00 0.03 0.00 0.13
0.57 0.25 0.27 0.07 0.00 0.40 0.17
0.57 0.32 0.10 b 0.13 0.03 0.07 0.13
0.00 0.04 0.00 0.00 0,00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.23 0.25 0,00 0,00 0.00 0.00 0.03
0.47 0.18 0.07 0.00 0.00 0.00 0.07
0.23 0.04 0.20 0.07 0.03 0.00 0.07
0.43 0.00 0.27 0.13 0.03 0.00 0.30 c
0.13 0.00 0.00 0.00 0.00 0.00 0.00
0.03 0.00 0.00 0.00 0.00 0.00 0.00
0.03 0.14 0.13 0.03 0.47 0.13 0.00
0.03 0.00 0.13 0.13 0.37 0.17 0.03
0.07 0.00 0.03 0.00 0.07 0.03 0.20
0.10 0.00 0.00 0.00 0.00 0.00 0.33
0.03 0.00 0,03 0.07 0.00 0.00 0.00
0.20 0.04 0.40 0.07 0.03 0.10 b 0.13 c
0.07 0.00 0.00 0.00 0.00 0.00 0.03
0.00 0.00 0.00 0.00 0.00 0.00 0.10
0,00 0.00 0.00 0.00 0.00 0.00 0.00
0.07 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.04 0.00 0,00 0.00 0,00 0.00
0.07 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.37 0.00 0.00 0.00 0.00
0.00 0.00 0.10 ' 0.00 0.00 0.00 0.00
0.00 0.00 0.03 0.03 0.37 0.07 0.07
0.00 0.00 0.10 0.10 0.47 0.00 0.23 a
0.03 0.00 0.00 0.00 0.00 0.00 0.00
0.03 0.00 0.00 0.00 0.00 0.00 0.00
0.10 0.04 0.17 0.03 0.03 0.00 0.00
0.20 0.25 0.00 0.00 0.00 0.07 0.00
0.00 0.00 0.00 0.00 0.00 0,00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.37 0.03 0.00
0.00 0.03 0.10 0.00 0.30 0.33 0.00
0.00 0.00 0.00 0.00 0.07 0.00 0.00
0.00 0.00 0.00 0.00 0.43' 0.03 0.00
0.00 0.04 0.07 0.00 0.00 0.17 0.07
0.00 0.00 0.00 0.00 0.00 0.00 0.03
0.10 0.00 0.20 0.00 0.00 0.07 0.53
0.07 0.00 0.03 b 0.00 0.00 0.43' 0.43
0.07 0.00 0,00 0,00 0.00 0.23 0.00
0.07 0.29' 0.00 0.00 0.00 0.47 0.10
0.00 0.07 0.13 0.00 0.07 0.00 0.00
0.00 0.00 0.33 0.00 0.03 0.03 0.00
0.03 0.07 0.00 0.00 0.00 0.10 0.00
0.20 0.00 0.03 0.00 0.00 0.03 0.00
APPENDIX 2. Continued.
Species Diet MCF MPP
Habitats
MC WLF LC LSF Ma LPa DLR DLF
Tennessee Warbler I 0.00 0.00 0.00
(Vermivora peregrina) 0.00 0.00 0.00
Northern Parula I 0.00 0.03 0.00
(Parula americana) 0.00 0.00 0.03
Yellow Warbler I 0.00 0.00 0.00
(Dendroica petechia) 0.00 0.00 0.00
Chestnut-sided Warbler I 0.00 0.00 0.00
(D. pensylvanica) 0.00 0.00 0.00
Magnolia Warbler I 0.00 0.00 0.00
(D. magnolia) 0.00 0.00 0.00
Cape May Warbler N 0.00 0.00 O00
(D. tigrlna) 0.00 0.03 0.00
Black-throated Blue Warbler I 0.30 0.47 0.49
(D. caerulescens) 0.30 0.37 0.21'
Yellow-rumped Warbler I 0.00 0.00 0.00
(D. coronata) 0.00 0.00 0.00
Black-throated Green Warbler I 0.00 0.00 0.00
(D, virens) 0.00 0.00 0.00
Yellow-throated Warbler I 0.00 0.00 0.00
(D. dominica) 0.00 0.07 0.00
Prairie Warbler I 0.00 0.00 0.09
(D. discolor) 0.07 b 0.07 0.18
Palm Warbler I 0.00 0.00 0.00
(D. palmarum) 0.00 0.00 0.00
Arrow-headed Warbler I 0.07 0.13 0.91
(D, pharetra) 0.15 0.20 0.00
Black-and-white Warbler I 0.07 0.17 0.00
(Mniotilta varia) 0.09 0.00' 0.03
American Redstart I 0.21 0.07 0.09
(Setophaga ruticilla) 0.15 0.03 0.12
Worm-eating Warbler I 0.00 0.03 0.00
(Helmitheros vermivorus) 0.02 0.00 0.00
Ovenbird I 0.05 0.03 0.00
(Seiurus aurocapillus) 0.00 0.00 0.00
Northern Waterthrush I 0.00 0.00 0.00
(S. noveboracensis) 0.00 0.00 0.00
Common Yellowthroat I 0.07 0.10 0.46
(Geothlypis trichas) 0.13 0.20 0.64
Hooded Warbler I 0.00 0.00 0.00
(Wilsonia citrina) 0.00 0.00 0.00
Bananaquit N 0.07 0.77 0.12
(Coereba fiaveola) 0.07 0.10 0.00'
European Starling I 0.00 0.00 0.00
(Sturnus vulgaris) 0.00 0.00 0.00
Jamaican White-eyed Vireo I 0.00 0.00 0.00
(Vireo modestus) 0.00 0.00 0.00
Blue Mountain Vireo I 0.23 0.20 0.00
(V. osburni) 0.15 0.03 0.00
Jamaican Oriole I 0.07 0.10 0.03
(Icterus leucopteryx) 0.00 b 0.00 0.00
Jamaican Blackbird I 0.07 0.00 0.00
(Nesopsar nigerrimus) 0.00 0.00 0.00
Greater Antillean Grackle I 0.00 0.00 0.00
(Quiscalus niger) 0.00 0,00 0.00
0.03 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.07 0,07 0.10 0.20 0.00 0.00 0.03
0.07 0.07 0.13 0.27 0.10 0.03 0.00
0.00 0.00 0.00 0.33 0.00 0.00 0.00
0.00 0.00 0.00 1.17 0.00 0.00 0.00
0.00 0.11 0.00 0.00 0.03 0.03 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.03 0.00 0.00 0.00 0.00
0.00 0.04 0.07 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.27 0.29 0.13 0.03 0.07 0.03 0.03
0.33 0.14 0.07 0.00 0.13 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
O00 0.00 0.00 0.03 0.00 0.00 0.00
0.00 0.21 0.03 0.00 0.00 0.00 0.00
0.00 0.07 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.03 0.00 0.03 0.00 0.00 0.00 0.00
0.00 0.18 0.07 0.03 0.30 0.17 0.07
O00 0.00 c 0.10 0.33 e 0.03 d 0.00 ' 0.03
0.00 0.04 0.00 0.00 0.27 0.03 0.00
0.00 0.00 0.00 0.03 0.50 0.07 0.00
0.10 0.00 0.00 0.00 0.00 0.00 0.00
0.07 0.00 0.00 0.00 0.00 0.00 0.00
0.10 0.29 0.07 0,40 0.13 0.03 0.10
0.13 0.04' 0.03 0.37 0.03 0.03 0.03
0.17 0.11 0.57 0.57 0.10 0.10 0.13
0.27 0.04 0.43 0.57 0.03 0.03 0.17
0.07 0.00 0.00 0.00 0.00 0.00 0.03
0.03 0.00 0.00 0.00 0.00 0.03 0.13
0.10 0.21 0.07 0.07 0.03 0.10 0.10
0.00 b 0.04 b 0.00 0.00 0.00 0.07 0.00 b
0.00 0.00 0.00 0.87 0.00 0.00 0.00
0.00 0.00 0.03 0.83 0.00 0.00 0.00
0.00 0.07 0.27 0.37 0.33 0.03 0.00
0.03 0.18 0.43 0.37 0.43 0.00 0.00
0.00 0.00 0.00 0.00 0.00 0.00 0.03
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.07 0.00 0.83 0.37 0.33 1.23 0.23
0.53 0.25' 0.67 0.20 0.10 0.93 0.57
0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.00 0.03 0.00 0.33 0.00 0.00
0.17 0.00 0.30 0.07 0.03 0.20 0.13
0.30 0.00 0.17 0.13 0.00 0.10 0.43
0.07 0.00 0.00 0.00 0.00 0.00 0.00
0.03 0.00 0.00 0.00 0.00 0.00 0.00
0.10 0.04 0.27 0.13 0.10 0.00 0.10
0.03 0.00 0.23 0.07 0.067 0.17 c 0.10
0.03 0.00 0.00 0.00 0.00 0.00 0.00
0.07 0.00 0.00 0.00 0.00 0.00 0.00
0.00 0.14 0.00 0.23 0.03 0.03 0.00
0.00 0.07 0.07 0.10 0.00 0.00 0.00
P < 0.15. bP < 0.10. cP < 0.05. d P < 0.01. eP < 0.005. P < 0.001.