Edited by John A. Smallwood
MISCELLANEOUS
1. Maximum dive depths attained by auks feeding young on the Isle of May,
Scotland. M.P. Harris, H. Towll, A. F. Russell, and S. Wanless. 1990. Scottish Birds 16:
25-28.--Maximum dive depths were measured by means of inexpensive gauges attached
to the upper-back feathers of 1 3 Common Guillemots (Uria aalge), 1 2 Razorbills (Alca torda),
and 10 Atlantic Puffins (Fratercula arctica). Each gauge consisted of a 10-cm length of
flexible plastic tubing (1.6 mm internal diameter) marked at 1-cm intervals, sealed at one
end, and lined internally with a thin layer of soluble indicator (powdered sugar). As the
gauge is carried underwater, pressure forces liquid into the tube, melting the sugar. Max-
imum depth (in meters) was calculated by the equation d = 10.08 (L,/Lr - 1), where L,
and Lf are the initial and final lengths of indicator in the tube. Repeated submergences of
the gauges to a constant depth, however, may allow additional water to be forced into the
tubes, resulting in overestimation of depth. The authors were able to overcome this problem
by reading the gauge with a 60 x telescope upon each bird's return from a single foraging
trip. Median depths recorded for guillemots was over 40 m, and ranged from 10-52 m.
Razorbills dove from 14-32 m deep (median value was 23 m) and puffins dove from 21-
33 m deep (median value was 25.5). [Inst. of Terrestrial Ecology, Hill of Brathens, Banchory,
Aberdeenshire AB31 4BY Scotland.]--J. A. Smallwood.
2. Censuslng of diurnal raptors in a primary rain forest: comparative methods
and species detectability. J. M. Thiollay. 1989. J. Raptor Res. 23:72-84.--As part of his
study of falconiform raptors inhabiting the lowland rain forest of French Guiana, the author
employed four survey methods: (1) mapping the movements of soaring territorial pairs, (2)
the number of individuals concurrently seen flying over a definite area, (3) mapping the
movements of birds seen or heard in the understory, and (4) an understory strip census. In
this paper, the methods are compared and recommendations are made in regard to various
forest species. The first method was appropriate for Gray-headed Kites (Leptodon cayanensis),
Hook-billed Kites (Chondrohierax unicinatus), Rufous-thighed and Double-toothed Kites
(Harpagus diodon and H. bidentatus), Tiny and Bicolored Hawks (Accipiter superciliosus and
A. bicolor), Gray-bellied Goshawks (A. poliogaster), White Hawks (Leucopternis albicolis),
Great Black-Hawks (Buteogallus urubitinga), Grested Eagles (Morphnus guianensis), Black-
and-White Hawk-Eagles ( Spizastur melanoleucus ), Black Hawk-Eagles ( Spizaetus tyrannus ),
and Ornate Hawk-Eagles (S. ornatus). An instantaneous count was appropriate only for
Gathartid vultures and American Swallow-tailed Kites (Elanoides forficatus). For most spe-
cies, the author recommends using several complementary methods; however, the forest-
falcons (Micraster spp.) and caracaras (Daptrius spp.) were censused effectively by only one
method each, mapping understory movements and the strip census, respectively. Because of
differences in species detectability, an abundance index (such as mean number of individuals
observed per hour) is comparable within but not between species. [Lab. d'Ecologie, E.N.S.,
46, rue d'Ulm, 75230 Paris, Gedex 05, France.]--J. A. Smallwood.
BANDING AND LONGEVITY
(see also 7, 10, 22)
3. The Bartos trap: a new raptor trap. R. Bartos, P. Olsen, and J. Olsen. 1989. J.
Raptor Res. 23:117-120.--This paper describes the construction and use of a trapping
device developed by the senior author. The Bartos trap is a new member of the family of
automatically triggered bow nets. The trap differs from other bow nets in that the bow
mechanism is located at the top of a funnel shaped enclosure. The trap consists of two
compartments: the upper compartment is open on the top and has the trigger mounted on
its base, while the lower compartment holds the lure animal. The trap has several advantages
over other bow netting systems. The trap may be set in a variety of configurations on the
ground or suspended in the air. When sprung, the captured bird is enclosed in the top
compartment. When the trap is set above ground, the captured bird should be fairly safe
from predators; therefore, this set need not be continuously monitored. The trap is inex-
pensive, lightweight, and collapsible. [Lot 5 Lamont Close, Mardi, NSW 2259 Australia.]--
J. A. Smallwood.
MIGRATION, ORIENTATION, AND HOMING
(see also 21, 22, 24)
4. Sunset orientation of Robins, Erithacus rubecula, with different fields of sky
vision. R. Sandberg. 1991. Behar. Ecol. Sociobiol. 28:77-83.--The author conducted a
series of orientation cage experiments on migratory Robins in Sweden from early September
through the first wcck of Novembcr in 1987-1988. Thc focus was to dctermine whethcr
these birds use visual and nonvisual orientation cues differentially depending on the par-
ticular migratory situation thcy cxperience. Robins tested with the visible sky scction rcduced
to 90 ø around the sunset zenith exhibited a mean orientation almost precisely towards the
average sunset azimuth, with little scatter around the mean angle. Converscly, when the
birds had a more extensive view of the sunset sky (160ø), they oriented in a north-south
distribution significantly differcnt from the reduced sky vision and from the arcrage sunset
position (P < 0.05 in both cases). Among birds exposed to the limited sky, no significant
differences in mean migratory direction or in concentration of headings were detectcd between
early and late tcsts (run beforc rs. after 7 October). However, birds exposed to thc 160 ø
horizon yielded a significant difference in mean orientation between early and late tests (P
< 0.02), but not in scatter of headings (P) 0.05). In addition, experiments using mirrors
to create a counterclockwise deflection of visual sunset cues resulted in a clear deflection of
preferrcd directions by Robins from a southwesterly mcan orientation toward more easterly
headings. These results indicate the importance of either an unrestricted view of the sunset
sky or, more specifically, of visual information close to the horizon in order for Robins to
achieve accurate migratory orientation. Differences in the orientation behavior of birds
exposcd to different manipulatory cffects of the magnctic field suggcst that their migratory
cues may vary depending on the specific circumstances associated with thc migratory effort.
[Dept. of Ecology, Univ. of Lund, S-223 62 Lund, Sweden. I--Danny J. Ingold.
5. Inheritance of migratory direction in a bird species: a cross-breeding exper-
iment with SE- and SW-migrating Blackcaps (Sylvia atricapilla). A. J. Helbig. 1991.
Behar. Ecol. Sociobiol. 28:9-12.--Young of thc ycar of many migrating passefine bird
species are able to migrate long distances to species- or population-specific wintering grounds.
The author crossbred hand-raised Blackcaps from Germany (near Frankfurt/M. and Ra-
dolfzell) and eastern Austria (a total of 16 pairs) in order to study the mode of inheritance
of thcir autumn migratory behavior pattcrns. The F1 offspring (n = 68) oricnted toward
mean directions that were significantly different (P < 0.05) from both parent populations.
The directional choices of thc F1 hybrids were not significantly linked to the sex of their
respective parents, nor were there any significant differences in mean orientations among
siblings versus non-siblings. The data show that population-specific migratory dircctions in
the Blackcap have a genetic basis which can be altered by cross-breeding. Moreover, since
the F1 generation was phenotypically intcrmediate betwccn both parental groups, there
likely is a polygcnic basis to thc trait (or lcss likely a singlc locus without dominancc).
[Max-Planck Inst. f/.ir Verhaltensphysiologie, Vogelwartc Radolfzell, W-7760 M3ggingen,
Germany. I--Danny J. Ingold.
6. Shorebird migration at artificial fish ponds in the prairie-forest ecotone of
northwestern Arkansas. K. G. Smith, J. C. Neal, and M. A. Mlodinow. 1991. Southwest.
Nat. 36:107-113.--Migrating shorebirds were monitored at a 23.2-ha fish hatchery in
Benton County from March 1981 through September 1988 in order to deterine species
occurrence and the relative abundance and frequency of each species. Twenty-five species
occurred during spring most years, and most of these passed through the region between
mid-April and late May. Semipalmated, Least, White-rumped, and Stilt sandpipers (Calidris
pusilla, C. rninutilla, C. fuscicollis, and C. hirnantopus, respectively) were most numerous,
while Killdeer (Charadrius vociferus), Lesser Yellowlegs (Tringa flavipes), Common Snipe
(Gallinago gallinago), and Least, White-rumped, and Semipalmated sandpipers were the
most frequently observed spring species. Twenty-three species occurred during fall migration,
mostly in August and September. The most abundant fall species was the Pectoral Sandpiper
(Calidris melanotos), while Killdeer, Least and Pectoral sandpipers, and Common Snipe
were observed most frequently. Fall migration occurred over a longer period of time than
spring migration due to adults of many species migrating first followed later by juveniles
in the fall. Some species, including the Lesser Golden-Plover (Pluvialis dominica), Willet
(Catoptrophorus semipalmatus), Short-billed Dowitcher (Limnodromus griseus), Wilson's
Phalarope (Phalaropus tricolor), and Semipalmated, Least, Stilt, and Baird's (Calidris bairdii)
sandpipers, had larger peak numbers in spring than in fall. These species are trans-Atlantic
migrants during fall and usually migrate east of the Great Plains. This study demonstrates
the importance of artificial bodies of water which serve as secondary stop-over sites for
migrating shorebirds. [Dept. of Biological Sciences, Univ. of Arkansas, Fayetteville, AR
72701 USA.I--Danny J. Ingold.
7. Fall movement of Black-capped Chickadees analyzed through banding re-
encounters. E. W. Brooks. 1991. N. Am. Bird Bander 16:l-8.--The author examined all
(n = 83) records of Black-capped Chickadees (Parus atricapillus) banded during fall (here
defined as 1 August to 12 January), 1922 through 1988, and re-encountered in a different
10-minute block the same season. Movement patterns during years of chickadee irruptions
were compared to those of nonirruptive years. Short distance movements (less than 20 km)
were analyzed separately from longer distance movements. The number of re-encounters
in irruptive years was twice that of nonirruptive years, both for short and long distance
movements. For long distance movements, the average distance moved during irruptive years
(234 km) was greater than that during nonirruptive years (96 km), as was the average rate
of movement (5.9 versus 2.6 km/day). In the northeastern United States, movements of
hatching year (HY) birds were compared to those of older (after hatching year, AHY) birds.
The author concludes that most HY birds took a coastal route while AHY birds were equally
likely to take a coastal or inland route.
The author suggests that the results of this study differ from several other reports relating
to fall migration in chickadees. One quarter of the known-age birds which underwent a
long distance movement were AHY birds; this is contrary to a cited suggestion that only
HY chickadees migrate. Six (27%) HY birds in the Northeast took inland routes while four
(57%) AHY birds took coastal routes, contrary to the generalization that adults move inland
while HY birds travel along the coast. Also, movements occurred between 1 November and
7 January in nine (11%) of the birds which moved. The author expresses "skepticism of
studies which based survival rates of chickadees on site tenacity between 1 November and
1 March" (i.e., Brittingham and Temple, 1988, Ecology 69:581-589).
The importance of these conclusions is difficult to assess due to sample size considerations.
In regard to age specific migration routes, the trend found in this study was, in fact, that
HY birds were more likely than AHY birds to follow the coast; however, this difference
was not significant (Fisher's exact test, P = 0.89). Given the relatively small sample size (n
= 29), the reader should be particularly cautious in drawing inferences based on failing to
reject the null hypothesis. In regard to movements during the period 1 November to 1 March,
only nine of "nearly 15,000" re-encounters indicated movements beyond the 10-minute block
during that period. The reader is not told how many total re-encounters occurred during
that period; it is possible that movement then is extremely rare. [1435 Waterwells Rd.,
Alfred Station, NY 14803 USA.]--J. A. Smallwood.
POPULATION DYNAMICS
(see 14, 17, 19)
NESTING AND REPRODUCTION
(see also 10, 12, 14, 16, 23)
8. Natural history of the American Kestrel in Venezuela. T. G. Balgooycn. 1989.
j. Raptor Res. 23:85-93.--American Kestrels (Falco sparverius) were studied in western
Venezuela from December 1982 to May 1983. Thirty-six kestrels were collected for mor-
phometric data. These kestrels were smaller than North American kestrels (e.g., mean
weights for males were 95.0 versus 103.7 g, and for females 108.1 versus 117.7 g), but
exhibited sexual size dimorphism similar to that of northern birds. The breeding behavior
of kestrels in the study area was similar to that observed in North America, except that the
[mean?] size of the defended area was only 0.12 km 2, compared to 0.24-5.86 km 2 for cited
North American studies. The author reports on nest sites, territory defense, copulations,
prey transfers, eggs and young, nesting success, predation, and caching behavior. [Dept. of
Biological Sciences, San Jose State Univ., San Jose, CA 95192 USA.]--J. A. Smallwood.
BEHAVIOR
(see also 8, 14, 15, 18, 24)
9. Do Common Ravens yell because they want to attract others? B. Heinrich and
J. M. Marzluff. 1991. Behav. Ecol. Sociobiol. 28:13-21.--Animal species aggregate in large
numbers at localized food bonanzas using a variety of means, including cuing in on specific
signals given by those discovering food. Signals such as vocalizations often attract a crowd
and thus facilitate recruitment or information parasitism (recruitment occurs when the
assembled group enhances the signaler's fitness whereas information parasitism decreases
the signaler's fitness). In the northeastern United States, non-breeding vagrant Common
Ravens (Corvus corax) frequently assemble in large numbers at carcasses to feed. In previous
studies, the authors concluded that the ultimate function of such group formation was to
enable juveniles to overpower territorial adults and access defended foods unavailable to
single birds (thus group formation constitutes recruitment).
In this study the authors conducted an experiment on 20 immature and two adult ravens
in an aviary to determine the proximate factors that elicit the "yell" vocalization (which
attracts nearby conspecifics to large carcasses). Hunger and placement of food significantly
influenced yelling rate and the number of birds yelling (P < 0.01). Immatures yelled more
frequently as their hunger levels increased; however, a relative reduction in their yelling
was noticable when food was placed with the increasingly hungry adults. Yelling also was
modified by social status such that alpha birds actively suppressed the yelling of other
dominants. However, when dominant birds were removed from the flock, new birds con-
sistently yelled for the first time. Moreover, when dominant birds were reintroduced, the
percentage of group yelling remained high rather than returning to previous levels (and
previously dominant birds were unable toi reestablish their former dominant status within
the flock). These results suggest that hunger and status advertisement are the primary
proximate factors that result in yelling, even though it has likely been amplified by natural
selection because of the benefits of group foraging. [Dept. of Zoology, Univ. of Vermont,
Burlington, VT 05405 USA.]--Danny J. Ingold.
10. Color bands function as secondary sexual traits in male Red-winged Black-
birds. K. J. Metz and P. J. Weatherhead. 1991. Behav. Ecol. Sociobiol. 28:23-27.--The
results of numerous studies indicate that the red epaulets of male Red-winged Blackbirds
(Agelaius phoerziceus) function as signals of threat during territorial defense, but also may
be concealed and thus serve as indicators of social status. In order to assess the effects of
additional red coloration on male red-wings, the authors equipped each of 19 territorial
males with five red plastic color bands (three on one leg and two on the other), and 19
others with five black bands near Seeley's Bay, Ontario (during 1989). Red-banded males
suffered increased intrusion rates on their territories, particularly by neighbors banded with
black or unbanded. While all 19 black-banded males were able to maintain their territories,
11 of 19 red-banded males lost their territories to other males (4 to black-banded neighbors
and 7 to unbanded neighbors). Although losers were neither smaller nor weighed less than
winners, they possessed larger epaulets relative to their body mass than red males that
retained their territories. These results indicate that red bands somehow interacted with the
red epaulets of males in a way that solicited an increased aggressive response against them.
Moreover, the data suggest that neighboring territorial red-wings continually test one an-
other's competitive ability relative to the amount of red coloration they possess, thus pre-
venting males from displaying dishonest signals. [Dept. of Biology, Carleton Univ., Ottawa,
ON K1S 5B6 Canada.l--Danny J. Ingold.
11. Observations of autumnal courtship behavior in Peregrine Falcons. A. J.
Meier, R. E. Nobel, and P.M. McKenzie. 1989. J. Raptor Res. 23:121-122.--Peregrine
Falcons (Falco peregrinus) frequently maintain pair bonds after the breeding season, and
some individuals apparently mate for life. Intrapair social interactions of peregrines outside
the breeding season have been poorly studied. In this report the authors describe courtship
behavior of two pairs of peregrines during October on an island in Puerto Rico. One pair
consisted of two adults while the other consisted of an adult female and a male in juvenal
plumage. Observed behaviors included undulating flights, soaring, stooping, hitched-wing
displays, aerial talon locking and tumbling, vocalizations, and one instance of copulation.
[School of Forestry, Wildlife and Fisheries, Louisiana State Univ. Agricultural Center,
Baton Rouge, LA 70803 USA.]--J. A. Smallwood.
12. Responses of breeding American Kestrels to live and mounted Great Horned
Owls. N. W. Gard, D. M. Bird, R. Densmore, and M. Hamel. 1989. J. Raptor Res. 23:
99-102.--Breeding American Kestrels (Falco sparverius) frequently direct interspecific ag-
onistic behavior toward other cavity nesters and potential predators. The purpose of this
study was to examine the aggressive behavior of kestrels toward Great Horned Owls (Bubo
virginianus) intruding within an occupied kestrel territory. Kestrels breeding in nest boxes
in southwestern Quebec were presented live and taxidermic mounts of owls. As a control,
a live white Leghorn chicken (Gallus domesticus) whose feathers had been dyed brown to
mimic the owl coloration also was presented. Intruder birds were placed either 10, 50, or
100 m from the nest box. Kestrel responses during 10 minutes of presentation included
number of calls and number of stoops. Trials were conducted during two phases of repro-
duction: incubation and nestling. In general, live owls elicited responses from more kestrel
pairs than did taxidermic mounts or the control chicken, and those responses were more
intense. Likelihood of response and response intensity were inversely related to the intruder
bird's distance to the nest box. Kestrels behaved similarly during the incubation and nestling
phases. [Macdonald Raptor Research Centre, Macdonald College of McGill Univ., 21111
Lakeshore Rd., Ste. Anne de Bellevue, PQ H9X 1C0, Canada.]--J. A. Smallwood.
13. Unusual roost site selection and staging behavior of Black-shouldered Kites.
W. S. Clark and B. K. Wheeler. 1989. J. Raptor Res. 23:116-117.--Black-shouldered
Kites (Elanus caeruleus leucurus) are known to form communal night roosts during winter.
These aggregations typically consist of tens of birds perched in trees. In this paper the
authors describe their observations of a group of over 100 individuals which roosted com-
munally in a sugar cane field in southern Texas. Groves of large trees, apparently suitable
for roosting, were within sight of the cane field. Not only were the number of birds involved
and the choice of roosting site unusual, but the birds also exhibited staging behavior prior
to roosting, not previously reported for this species. Prior to flying together in the cane field,
the birds first gathered close together on the ground in a recently plowed field. [4554 Shetland
Green Rd., Alexandria, VA 22312 USA.]--J. A. Smallwood.
ECOLOGY
(see also 9, 18, 22, 24)
14. Seablrd llfe histories and the marine environment: some speculations. R. E.
Ricklefs. 1990. Colon. Waterbirds 13:l-6.--Seabirds share life history characteristics of
low reproductive rates, delayed reproductive maturity, and long developmental periods and
lifespans. In this guest editorial Ricklefs urges the rethinking of seabird population dynamics,
behavioral mechanisms, and evolution as shaped by the interactions of birds and their
environment. He suggests that the traditional paradigms are no longer consistent with
observation and experimental results (e.g., brood-enlargement experiments) and hence the
standard explanations for seabird life history phenomena need to be re-examined. He offers
speculative hypotheses and suggests research directions to test them for a number of problem
areas, including reproduction rates, adipose tissue in nestling petrels, long incubation periods,
slow postnatal growth, long prereproductive periods, and population regulation factors. He
suggests investigating density-dependent depression of food supplies and differences between
nearshore and pelagic species' exploitation of marine resources. The author concludes that
seabirds make suitable study animals for investigating a wide variety of biological problems.
This is a heuristic paper with lots of speculation and many challenging ideas. It should
be read by all seabird biologists, even if they might not agree with all the arguments the
author presents. [Dept. of Biology, Univ. of Pennsylvania, Philadelphia, PA 19104 USA.]--
William E. Davis, Jr.
15. Inter- and intra-specific diet overlap during lean times between Quelea
erythrops and bill morphs of Pyrenestes ostrinus. T. B. Smith. 1991. Oikos 60:76-82.--
Inter-specific competition for food resources results in more specialized feeding strategies,
as suggested by Schoener (1982, Am. Sci. 70:586-595). This hypothesis predicts that com-
peting species shift their foraging habits to dissimilar food sources. Smith monitored the
seed ingestion of the ploceid finch, Quelea erythrops, and two different bill morphologies of
the African estrildid finch, Pyrenestes ostrinus. He noticed that the ploceid finch most closely
matched the small billed estrildid finch in beak size and seed preference. His results showed
that a dramatic decline in the number of seeds available corresponded to a shift toward
feeding on harder seeds by the small estrildid finch morph. The small morph's switch to
the harder seed increased its overlap with the larger morph. The reduced overlap between
species lends strong evidence to inter-specific competition, but Smith needs to explain further
how an increase in foraging overlap demonstrates intra-specific competition. [Dept. of In-
tegrative Biology, Univ. of California, Berkeley, CA 94720 USA.]--T. A. Keller.
WILDLIFE MANAGEMENT AND ECONOMIC ORNITHOLOGY
(see also 2, 6, 17, 25)
16. Hazards to raptors from strychnine poisoned ground squirrels. J. K. Schmutz,
K. A. Rose, and R. G. Johnson. 1989. J. Raptor Res. 23:147-151.--In many agricultural
regions populations of unwanted rodents are "controlled" through poisoning campaigns.
This practice has raised the concern over the potential harm posed to nontarget species,
which may either ingest the poison bait directly or be exposed to toxins secondarily through
the consumption of the poisoned carcasses of target animals. Many raptorial species fall
into the latter category. Nestling raptors may be particularly vulnerable to this sort of
exposure, as there is less opportunity to select prey. This study was conducted in a mixed-
grass prairie in Alberta, Canada, where Richardson's Ground Squirrels (Spermophilus
richardsonii) frequently are the target of poisoning campaigns. In this area ground squirrels
comprise more than 65% of the prey biomass consumed by Swainson's Hawks (Buteo
swainsoni). The purpose of this study was to simulate the field conditions under which
Swainson's Hawk nestlings are exposed to poisoned ground squirrels, and to evaluate the
potential deleterious effects of such exposure.
Ground squirrels were captured and fed oats which had been treated with a commercial
rodenticide (2% strychnine, applied according to label instructions); most died within 12
hours. Squirrel carcasses were eviscerated and deposited, one carcass each day for three
consecutive days, into Swainson's Hawk nests. The three-day period was chosen to simulate
the duration of a typical poisoning campaign. Nestling growth and survival was compared
to that of control nests. A total of 52 nestlings consumed 67 poisoned ground squirrels; 49
of these chicks survived the treatment period. Survivorship did not differ significantly (P >
0.19) from that of the control nests (all 28 control chicks survived the 3-day period. Forty-
two (72%) treated chicks reached banding age (3-21 days after treatment), compared to 28
(82%) control chicks; this difference also was insignificant (P > 0.32). Further, during the
three days of treatment there was no significant difference (P > 0.79) in weight gain between
treatment and control chicks.
The result that poisoned carcasses apparently had little effect on the growth and survival
of the chicks was unexpected by the authors. They suggest that evisceration of the carcasses
likely was an important factor. Squirrels probably die very quickly once the strychnine is
absorbed from the gastrointestinal tract into the bloodstream; thus toxicity levels in consumed
tissues probably were rather low. The authors warn, however, that although many raptor
species regularly discard the viscera of large prey, smaller prey often are eaten entirely, and
the viscera of large prey may be eaten during times of food stress. Further, some of the
squirrels died with poisoned grain still in their cheek pouches, which could pose a threat
to the predator. Finally, the results must be viewed in light of several uncontrolled variables
which existed during the experiment. The authors point out that it is unknown how much
"clean" food was brought to the treated nests by the adult hawks. Also, it may be possible
that the control nests may have been exposed to prey contaminated as the result of agricultural
practices rather than by the experimental treatment. [Dept. of Biology, Univ. of Saskatch-
ewan, $askatoon, $K S7N 0W0, Canada.]--J. A. Smallwood.
CONSERVATION AND ENVIRONMENTAL QUALITY
(see also 6, 16)
17. Status of the Greater Flamingo in Haiti. J. A. Ottenwalder, C. A. Woods, G.
B. Rathburn, and J. B. Thorbjarnarson. 1990. Colon. Waterbirds 13:115-123.--There is
concern about recent population declines of the Greater Flamingo (Phoenicopterus tuber) in
the Caribbean area, and there is little published information on the status of this species in
Haiti since 1928. Aerial surveys of traditional flamingo habitat in 1982 and 1983 were
supplemented by flamingo counts made during manatee, sea turtle, crocodile, seal, and
opportunistic ground surveys conducted from 1975-1986. The authors report flamingo
numbers and present detailed descriptions of localities and habitats, as well as a thorough
review of historical reports. They found no evidence of flamingo breeding activity, and the
last report of nesting dates back to the 1920s. The authors estimate that the flamingo
population is as high as 1000-3000 during the non-breeding winter season, and suggest
that local populations recently have declined. One factor which may have influenced the
decline is human population increase with 80% of the people living in rural areas. Flamingos
generally are found in the dry life zones where human population density is low. Flamingos
also are captured for the international bird trade, and heavily hunted for food. Habitat
degradation, such as clear cutting of mangroves, also is implicated in the decline. The authors
recommend that the Haitian government initiate conservation practices, including the legal
protection of flamingos, and management plans for the conservation of wetlands. [Dept. de
Zoologla, Investigaci6n y Conservaci6n, Parque Zoo16gico Nacional, Apt. 2449, Santo Do-
mingo, Repfiblica Dominicana.]--William E. Davis, Jr.
PHYSIOLOGY
(see 14, 24)
MORPHOLOGY AND ANATOMY
(see 8, 15)
PLUMAGES AND MOLTS
(see also 10)
18. The significance of subadult plumage in Darwin's finches, Geospiza fortis.
B. R. Grant. 1990. Behav. Ecol. 1:161 - 170.--Gradual acquisition of definitive adult plumage
is common among male passerines. By way of introduction the author reviews the three
major hypotheses postulated to explain this phenomenon. First, the cryptic hypothesis states
that young males, which are competitively inferior to older, more experienced males, enhance
their chances of survival to later age classes by being inconspicuous. Second, the female
mimicry hypothesis suggests that young males gain access to territories and females by
dishonestly signaling their gender, and thus avoid being expelled by older males. Third, the
status-signaling hypothesis states that competitively inferior males avoid contests with older
males by honestly signaling subordination; survival to subsequent age classes is enhanced
by reductions in energy expenditure and risk of injury.
In the present study, the author observed color banded Darwin's finches (Medium Ground
Finches) on Isla Daphne Major in the Galfipagos and empirically examined the fitness
consequences of possessing different plumage stages during different age classes. Male finches
initially are brown and streaked, and through successive molts acquire entirely black plum-
age. Six plumage stages were recognized. The rate at which males acquired definitive
plumage ranged from two to more than six years. Heritability of acquisition rate was
examined by comparing the plumge stage of fathers and sons during an equivalent age (their
second year). Heritability was significant (P < 0.02, n = 19); thus acquisition rate may be
considered a lablie trait.
Breeding in Darwin's Finches is tied closely to the wet season. Annual variation in rainfall
is extreme, and in dry years the birds forego breeding altogether. Thus, longevity is of
critical importance to the lifetime reproductive success of these birds. Males which took
longer to acquire definitive plumage were more likely to survive dry periods than were males
with faster acquisition rates. Enhanced survival was attributed to avoidance of conflict with
older males by signalling subordinate status during both breeding and nonbreeding seasons.
However, black males which did survive produced more fledglings in their first breeding
season than did lighter males of the same cohort. This study demonstrates the likely selective
mechanism which operates on plumage acquisition rate in this species. [Dept. of Ecology
and Evolutionary Biology, Princeton Univ., Princeton, NJ 08544 USA.]--J. A. Smallwood.
ZOOGEOGRAPHY AND DISTRIBUTION
(see also 2, 17)
19. An archeozoological contribution to the recent history of the seabirds of
Lavezzi Island (Corsica southern France, 14th-20th century). [Contribution archeo-
zoologique a l'histoire recente des oiseaux marins de l'Ile Lavezzi (Corse--XIVe-XX
siecles).] J-D. Vigne, C. Lefevre, J-C. Thibault, and I. Guyot. 1991. Alauda 59:11-21.
(French, English summary.)--Six species of seabirds are known to have nested in recent
years on Lavezzi Island between Corsica and Sardinia in the Mediterranean: Cory's Shear-
water (Calonectris diomedea ), British Storm-petrel (Hydrobates pelagicus), Shag (Phalacro-
corax aristotelis), Common Tern (Sterna hirundo), Auduoin's Gull (Larus audouinii), and
Yellow-legged Herring Gull (Larus argentatus cachinnans). In addition, two species, the
Great Cormorant (Phalacrocorax carbo) and Manx Shearwater (Punus p. yelkouan) are
regular visitors to the area. Of these eight species, the authors identified remains of adults
and immatures of Cory's Shearwater, Manx Shearwater, and Shag among about 1500 bird
bones excavated from middens at Santa Maria Lavezzi. These date from the 14th to 18th
centuries and apparently represent birds caught by human residents for food. Relative
abundance of bones suggests that Shag and Cory's Shearwater populations have remained
stable, that the Yellow-legged Herring Gull has recently increased in numbers, and that
the Manx Shearwater has declined. The potential predation of introduced black rats (Rattus
rattus) on young Manx Shearwaters is discussed.--Jerome A. Jackson.
20. Eurasian Tree Sparrow in Minnesota. R. B. Janssen and P. Svingen. 1990.
Loon 62:175-176.--The first sighting of a Eurasian Tree Sparrow (Passer montanus) in
Minnesota occurred at a bird feeder in Eagan, Dakota County, on 20 June 1990 (the bird
returned sporadically to the feeder through 6 July). Since there was no evidence that the
bird was an obvious escape or that it had been transported to the region, it was accepted as
the first state record as an accidental species. [10521 S. Cedar Lake Rd., #212, Minnetonka,
MN 55343 USA.]--Danny J. Ingold.
21. A Whooping Crane in Minnesota. M. Hedemark and W. D. Svedarsky. 1990.
Loon 62:177-181.--On 11 October 1990, the senior author sighted a single Whooping
Crane (Grus americana) among a flock of approximately 1000 Sandhill Cranes (G. canadensis)
in a plowed wheat field near Gatzke, in Marshall County. On 21 October 1990, the junior
author spotted a single Whooping Crane in a flock of about 5000 Sandhill Cranes on a
flood control impoundment on Burnham Creek Wildlife Management Area near Crookston
(Polk County). [Box 56 Rt. 2, Gatzke, MN 56724 USA.]--Danny J. Ingold.
EVOLUTION AND GENETICS
(see 5, 14, 18)
FOOD AND FEEDING
(see also 1, 8, 9, 14, 15, 16)
22. Evidence of food-based competition among passerine migrants during stop-
over. F. R. Moore and W. Yong. 1991. Behav. Ecol. Sociobiol. 28:85-90.--When inter-
continental migrants with similar food requirements and heightened energy demands con-
centrate at stopover sites, competition for available food resources may occur and could be
intense. In order to test this hypothesis, the authors conducted a series of predator-exclosure
experiments (designed to measure the effect of bird predation on foliage-dwelling arthropods)
as well as an intense mist-netting effort (to obtain the weights of migrants) from late March
through early May 1988 in Cameron Parish, Louisiana. Lepidopteran (Geometridae) larvae,
the most common prey item, were significantly more abundant inside exclosures on four of
six sampling dates (P < 0.05), indicating that migrants may have depressed food abundance
on the study site. Moreover, eight of nine species that stopped on days when the density of
birds was high (days when -100 migrants of any species were mist-netted) were less likely
to gain mass compared to low density days (days when -50 migrants were mist-netted).
These data suggest that food-based competition did occur among migrants at this stopover
site, reducing the probability of individuals to meet their energetic requirements. [Dept. of
Biological Sciences, Univ. of Southern Mississippi, Hattiesburg, MS 39406 USA.I--Danny
J. Ingold.
SONGS AND VOCALIZATIONS
(see also 9)
25. Song as an attractant for male and female European Starlings, and the
influence of song complexity on their response. D. J. Mountjoy and R. E. Lemon. 1991.
Behav. Ecol. Sociobiol. 28:97-100.--To test the hypothesis that female European Starlings
(Sturnus vulgaris) are attracted to nest sites by the songs of males, the authors conducted
playback experiments at a series of starling nest boxes at Ste. Anne de Bellevue, Quebec,
during two breeding seasons. Contrary to prediction, both females and males were attracted
toi song boxes at a significantly greater rate (P < 0.001) than to control boxes. Moreover,
females entered only those boxes in which a complex song consisting of 40 different phrase
types was used, whereas males were significantly more likely (P (0.01) to enter boxes
where a simpler song was played. These data not only demonstrate that singing by breeding
male starlings serves at least in part to attract females, but it also provides the first exper-
imental evidence that passerine song attracts intruding males into a "defended" area (i.e.,
territory). Males may be attracted by song because it often indicates the location of a
potentially suitable nest cavity that they may be able to usurp. On the other hand, males
that sing complex songs may discourage potential male intruders, as well as enhance their
chances of attracting females. [Dept. of Biology, McGill Univ., 1205 Ave. Docteur Penfield,
Montreal, PQ H3A lB1, Canada.]--Danny J. Ingold.
BOOKS AND MONOGRAPHS
24. Bird migration: physiology and ecophysiology. E. Gwinner, ed. 1990. Spring-
er-Verlag, New York. 435 pp. $110.--This volume contains excellent reviews, but few of
the papers contain any new material. Consequently, for workers familiar with the field, the
book does little more than bring together the scattered literature. For ornithologists not
current on the migration literature, the book provides a wealth of information in a single
volume. Unfortunately, its price will put it out of the reach of all but libraries and wealthy
ornithologists. Unlike previous volumes, this one deals with the physiology and mechanisms
of migration rather than on the orientation and navigation of migrants. The papers are
grouped into five topics: patterns of migration, ecological and behavioral aspects of migration,
physiological adaptations to migration, avian flight, and strategies and tactics of migration.
Williams and Williams summarize data on the overwater paths of migrants as they cross
specific oceans. Several large species of shorebirds appear to make longer flights than
previously suspected of 6000 to 7500 km nonstop in the western Pacific, between Australia
or New Zealand and China. Johnson and Herter report on bird migration to and from the
Arctic, where migrants make up 95% of the total number of arian species. They discuss
both the patterns of migration in the Arctic and the hypotheses on its evolution. Important
factors include weather, delaying migration, and low food availability, resulting in late
spring arrival and reproductive failure. Pearson synthesizes the published information on
the movement of passerines through Kenya and Uganda with his new data. Most birds
interrupt their migration and undergo molt in this area before continuing their migration
when the rains start. Many species use a more easterly route on their northward migration
than on their southward migration. Brudener and Jenni review the role of the Alps as a
barrier to European migrants. Migrants tend to follow ridges that are closely aligned to
their migratory direction, which results in a funneling of migrants between the Jura and
the Alps mountain ranges. Longer distance migrants with heavy fat stores are more likely
to cross the Alps than are southern populations. Richardson updates his 1978 review of the
influence of weather on the timing of migration. The new results confirm the findings he
reported earlier that birds generally tend to avoid migrating in inclement weather. Birds
most frequently fly with following winds, but other factors are more variable in their
influences. Jehl reviews and discusses molt migration in taxa other than the waterfowl
where it is best known. Many of the more primitive families show simultaneous molt of
the remiges, but not necessarily in the postbreeding molt. The resulting flightlessness is
associated with an atrophy of the flight muscles and a hypertrophy of the leg muscles,
reflecting the differences in locomotion.
The second group of papers deals with the ecological and behavioral aspects of migration.
Ketterson and Nolan review the evidence from field studies on the attachment of migratory
birds to specific sites and discuss the neural basis of site recognition. Although this site
attachment appears to be an imprinting-like process, it could just as easily be explained by
a gradual process that culminates in attachment. The question remains unanswered. Terrill
reviews the movements of migrants within their nonbreeding (=winter) ranges. Some species
are highly sedentary while others move about within their range. Unusually cold weather
and decreased food availability are associated with such facultative movements. Schwabl and
Silverin examine the factors that influence the variations in the tendency of individuals to
migrate and their autumnal departure. The importance of exogenous controls (social dom-
inance, weather, food, etc.) of partial migration remains to be tested. The influence of
endogenous (hormonal) control varies according to species and appears to be facultative.
Leisler discusses habitat selection and use by temperate-tropic migrants on their non-breeding
ranges. Migrant habitat selection is partially influenced by availability, but migrants show
low preferences for extensive mature forest, especially wet lowland forests. During com-
petitive interactions migrants never dominate year-round residents, but this does not result
in migrants being excluded from mixed-species flocks or suitable habitat. Although migrants
exhibit a greater flexibility of diet and habitat on their non-breeding ground than on their
breeding grounds, residents are morphologically more diverse. The ecological aspects of
migrants and residents is reviewed by O'Connor. Migrants exploit seasonally variable
habitats and are especially sensitive to diffuse competition from residents.
The third section of the book deals with the physiological adaptations to migration. Martin
examines the visual problems faced by nocturnal migrants. The importance of visual cues
to nocturnal migrants is well documented; in fact, they may be the most important source
of directional information. Not enough presently is known about their minimum sensitivity
thresholds to draw any conclusions, but they do not seem to be capable of distinguishing
details at night. Bairlein reviews the influence of nutrition and food selection on fat deposition
in migrants. The greatest weight gains (up to 100%) occur in long distance migrants. Weight
gains involve both hyperphagia and an increase in the efficiency of food (especially fat)
utilization; the converse applies to weight losses. Furthermore, studies have shown seasonal
shifts in food preferences. Fruit provides an easily digested diet high in fat, calories, and
water. Ramenofsky very thoroughly reviews fat storage and metabolism and its role in
supplying energy for migration. The flight muscles, especially of migratory species, are well
adapted to store and use fatty acids for energy. Lipolysis increases during migration to
supply the energetic demands. Wingfield, Schwabl and Mattocks review the effects of the
endocrine system on migratory behavior and physiology. These effects, in some species,
include hypertrophy of flight muscles and an increase in hematocrit. Although androgens
are involved in the preparation for vernal migration, they have no influence on autumnal
migration. A number of other hormones (thyroid, corticosteroid, prolactin, and catechol-
amines) have various influences on migratory physiology. Gwinner reviews the circannual
rhythm of bird migration and its controls. Circannual rhythms have been demonstrated
conclusively in 13 species of migratory birds, and appear to occur in an additional five
species. Although photoperiod is the overpowering synchronizing factor, the effects of long
and short days differ qualitatively and quantitatively. Berthold reports that the occurrence
of migration and its circannual regulation appears to be genetically transmitted. In spite of
this, there seems to be a great deal of plasticity in distance and direction traveled, such that
migrants can exploit newly formed, suitable habitats.
The fourth unit is more general and deals with several aspects of avian flight. The
mechanisms and energetics of flight are reviewed by Rayher. The production of lift by the
wing results in the creation of vortices. The strength of the vortex is indicative of the amount
of lift being produced, and its measurement permits the calculation of the energy required
for flight. As a result of the mechanical constraints on flight power and speed, most migratory
species are relatively small birds. The efficiencies of the flight muscle are around 0.10 in
small birds and increases with size. The physiological aspects of flight are reviewed by
Butler and Woakes, based primarily on data from birds flying in wind tunnels. In spite of
its shortcomings, the technique is the most accurate available. Power consumption during
flapping flight is about 10 times resting level and over twice the maximum metabolic rate
of small mammals. The pectoralis muscle is large, up to 35% of the body mass, and composed
primarily of fast oxidative glycolytic fibers in flying species. Avian circulatory and respiratory
systems are adapted to support the high metabolic demands of flight. Nachtigall reviews the
effects of long flights on energetics and water balance. During the first hour of flight pigeons
use carbohydrates for fuel then gradually switch to fats. Nonevaporative methods are used
to dissipate heat as long as possible because excessive evaporation may result in dehydration.
The final section deals with the strategies and tactics of migration. Alerstam and LindstrSm
discuss the role of fat deposition in the flight speed and range of migrants. The optimal
strategy for a migrant depends on its fat load more than fat deposition rates or time factors.
Foraging strategy depends on whether time, energy, or threat of predation is most important
to the migrant. The various strategies available to migrants crossing the Sahara are reviewed
by Biebach. No single strategy is used by all species and a species may use different strategies
in different seasons. The two most frequent strategies are to fly non-stop over the desert or
to fly at night and rest in the shade during the day. If the bird is able to maintain itself in
10øC air or cooler, it theoretically can balance evaporation with metabolic water production.
Depletion of fat reserves, inability to achieve cool air, and head winds make intermittent
migration a more economical strategy. Dolnik discusses the strategies used to cross inhos-
pitable desert and mountain habitats in central Asia. Much of the data he presents is new.
Birds had the heaviest fat loads in the least hospitable habitats: deserts, followed by moun-
tains. Birds in forested areas had the smallest fat deposits. Birds remaining at desert oases
were leaner than birds that passed through, and usually gained weight. There was much
intraspecific variation in fat deposits and rates of weight gain. Unlike migrants crossing the
Sahara, the basic strategy used by birds crossing central Asian deserts is to refuel during
stopovers. Evans and Davidson review the migration strategy used by shorebirds at high
northern latitudes. The migration patterns of subadult shorebirds is poorly understood.
Although first year birds of some species undertake the return journey to the breeding
grounds, the young of other species remain on their nonbreeding grounds. Shorebirds show
some plasticity in winter site philoparry. Competition between species may affect their
distribution during migration and on the non-breeding grounds. Flight muscle hypertrophy
during migration seems to be an adaptation for long overwater flights found in most shorebird
species. Drent and Piersma explore the energetics of "leap-frog" migration in several Arctic-
breeding shorebirds. Birds traveling farther show higher daily energy expenditures during
the southward movement, but the data from northward migration are less clear. Presumably
this migration pattern results in less intraspecific competition. Walsberg discusses the prob-
lems facing researchers investigating the energetics of migration. Obtaining energetic data
from flying birds is difficult, involving either birds flying in a wind tunnel wearing a mask
and associated apparatus, or unencumbered birds using doubly labeled water. Unfortunately,
both techniques have their shortcomings. These can be partially compensated by an increased
sample size and improved theoretical approaches to the problem.--Robert C. Beason.
25. The dove chronicles: whistling wings. H. E. McClure. 1991. Boxwood Press,
Pacific Grove, California. 99 pp. $9.95, softcover.--This book is a popular tale written
somewhat in the genre of Thornton W. Burgess of "Adventures of Prickly Porky" and the
"Old Mother West Wind" stories of a couple generations ago--but with a much more
factual thread to the story. McClure follows the lives and adventures of "Zee" and "Naida,"
a pair of Mourning Doves (Zenaida raacroura), and their friends (most with Indian names
meaning "dove" or somesuch). Although extremely anthropomorphic, this book will appeal
to some audiences and it does accurately portray the species' natural history and the travails
that Mourning Doves must face: flimsy nests that are easily blown down, disease, and
hunters.
Ah yes, hunters. Militant hunters will no doubt take exception to this book--and no
doubt militant anti-hunters will embrace it. The story is emotionally charged. One of the
characters, "Stump Face," survived having his beak blown away. Perhaps the emotion is
justified. I've never understood the rationale for southern dove hunts in early September at
a time when many southern doves still have eggs or young in the nest. McClure questions
"Is this wildlife management?" Although not a scientific treatise, this should be on the
"must read" list of dove biologists and students in wildlife management or wildlife man-
agement ethics courses. It's provocative.--Jerome A. Jackson.