Edited by John A. Smallwood
RESEARCH TECHNIQUES
(see 21)
BEHAVIOR
1. Embryonic and neonatal vocal ellcltation of parental brooding and feeding
responses in American White Pelicans. R. M. Evans. 1992. Anim. Bchav. 44:667-675.--
Embryonic and neonatal American White Pelicans (Pelecanus erythrorhynchos) squawk when
cold or hot and neonatal white pelicans beg when hungry. Parents respond to squawks with
brooding and to prolonged bouts of begging with a characteristic feeding posture and
gurgitation of food. Parents responded to playback of the squawk call with brooding behavior
and to playback of begging calls with the feeding posture, but did not regurgitate food.
Responsiveness was similar whether the nest contained two unpippcd eggs, a pipped and
an unpippcd egg, a chick and an unpippcd egg, a chick and a pippcd egg, or two chicks.
These results indicate that vocal communication facilitates adjustment of parental behavior
to the needs of late-stage embryos and newly hatched chicks, but that feeding also depends
on optical communication between chick and parent. [Dept. of Zoology, Univ. of Manitoba,
Winnipeg, MB R3T 2N2, Canada.]--Edward H. Burtt, Jr.
FOOD AND FEEDING
(see also 1, 5, 6, 19, 27, 28)
2. Optimal foraging and timing processes in the starling, Sturnus vulgaris: effect
of inter-capture interval. D. Brunncr, A. Kacclnik, and J. Gibbon. 1992. Anim. Bchav.
44:597-613.--How does a foraging bird decide that a food patch is exhausted and the time
has come to look for a new patch? Researchers have assumed that birds measure time, but
Brunncr ct al.'s behavioral analysis of starlings is the first rigorous, manipulative test of
that assumption. Six starlings wcrc trained individually to perform a complex foraging task
that required 20 flights in 3.5 rain between two perches. If the flights wcrc completed within
the allotted time, a key at a food hopper was illuminated and a peck at the key might deliver
food after a fixed interval. Over the course of the experiment six different intervals wcrc
used. Each interval was used for 12 days and, when the interval was changed, birds wcrc
given a day to adapt to the new interval. Birds encountered 60 or more patches daily. Half
the patches had no food. The others had 1-4 food rewards, but always ended with an
unrewarded trial. The duration of pecking and the time at which travel resumed wcrc
measured on the unrewarded trial of each patch.
Starlings learned the task and wcrc able to adjust to changes in the fixed interval. Pccks/s
wcrc maximal at the time of food delivery, leading to the conclusion that starlings could
accurately estimate time. As the interval between the first peck and food delivery increased
from 0.8 s to 25.6 s, the time at which all pecking ceased (giving-in time) increased as a
constant proportion of the delivery delay. In all cases cessation of pecking occurred after
food should have bccn delivered. Thus starlings used a conservative giving-up rule that
ensured they had exhausted the patch before they travelled to a new patch. What is most
notable about the results is that starlings did not resume travel immediately after the last
peck, but paused up to 27 min before resuming flights between perches. Foraging theorists
have assumed that animals maximize their rate of consumption. Rate maximization predicts
that patches arc abandoned to move to another patch, but starlings in this experiment
abandoned the patch (i.e., stopped pecking) well before they moved to the next patch. The
authors emphasize this point, but offer no functional explanation for this striking violation
of the assumption of rate maximization. Clearly, there is anccd for field and laboratory
studies of the functional significance of the time between giving-up and the time of moving
on. [New York State Psychiatric Inst., Box 50, 722 W 168 St., New York, NY 10032,
USA.I--Edward H. Burtt, Jr.
3. Frugivory on Bursera rnicrophylla (Burseraceae) by wintering Gray Vireos
(Viero vicinior, Vireonidae) in the coastal deserts of Sonora, Mexico. J. M. Bates. 1992.
Southwest. Nat. 37:252-258.--In the coastal desert regions of Sonora, Mexico, two species
of elephant trees (genus Bursera) produce avian-dispersed aril-covered seeds during the
winter months. The fruits of B. hindsiana are large (mean diameter = 5.5 mm) and are
consumed by several bird species; the fruits of B. microphylla are much smaller and consumed
primarily by Gray Vireos and Ash-throated Flycatchers (Myiarchus cinerascens). Gray Vireos
are one of the few seasonally frugivorous birds that defend a territory throughout winter,
and the author reports from this two-year study that they feed almost exclusively on B.
microphylla. These data suggest that Gray Vireos, and to a lesser extent, Ash-throated
Flycatchers, are very dependent on the fruit of B. microphylla for up to seven months each
year. Given the absence of diversity of possible seed dispersers for B. microphylla, this
interaction may be strong enough for each species to exert reciprocal selection pressure on
one another, resulting perhaps in an obligatory mutualistic relationship. [Dept. of Zoology
and Physiology, Louisiana State Univ., Baton Rouge, LA 70803, USA.I--Danny J. Ingold.
SONGS AND VOCALIZATIONS
(see 1, 28, 30)
NESTING AND REPRODUCTION
(see also 9, 12, 15, 18, 28)
4. Observations on habitat use, breeding chronology and parental care in Bristle-
thighed Curlews on the Seward Peninsula, Alaska. R. E. Gill, R. B. Lanctot, J. D.
Mason, and C. M. Handel. 1991. Wader Study Group Bull. 61:28-36.--With only two
known nesting areas in western Alaska, the Bristle-thighed Curlew (Numenius tahitiensis)
is one of the rarest shorebirds in North America. Based on fieldwork conducted in 1989,
this paper presents the first data from the northern nesting area on the Seward Peninsula.
Point counts along transects revealed that "shrub meadow tundra" and "low shrub/
tussock" habitats were used by curlews throughout the breeding season, with increased use
of "sedge wet meadows" during brood-rearing. Aerial displays were seen as early as 18
May, and three copulations were observed between 27 and 30 May. Although no nests were
found, estimated ages of broods indicated that egg laying began in late May and hatching
in late June. Seventeen adults (nine males, eight females) were captured and marked. Females
attended broods for shorter periods than did their mates, with most (83%) abandoning their
broods before the young could fly. Several broods formed groups attended by 1-5 adults
that usually were males. At least two chicks joined groups that were not attended by their
parents; consequently, these brood groups were similar to creches. The authors suggest
several mechanisms that might lead to creche formation, including (1) improved efficiency
in mobbing predators, (2) convergence of broods around limited food resources, (3) improved
efficiency in vigilance, and (4) enhanced survival of kin via a selfish-herd mechanism. [Alaska
Fish and Wildlife Research Center, 1011 E Tudor Rd., Anchorage, AK 99503, USA.]--
Jeff Marks.
$. An experimental study of competition for food between male and female
nestlings of the Red-winged Blackbird. K. L. Teather. 1992. Behav. Ecol. Sociobiol. 31:
81-87.--Ten experimental broods of Red-winged Blackbirds (Agelaiusphoeniceus) consisting
of two males and two females were observed from April to July 1991 in order to determine
whether (a) nestling height, distance from the feeding parent, and begging sequence influ-
ences nestling success in obtaining food, and (b) heavier male nestlings differ from females
in any of these characteristics. In every nest, nestlings that reached higher during feeding
bouts were significantly more likely to be fed (P < 0.0001); on the other hand, distance
from the parent and nest position did not influence whether or not a nestling was offered
food. The importance of begging sequence was difficult to interpret since in seven nests it
appeared to influence which nestlings were fed, while in three others, no correlation was
detected. Size and sex were influential in determining which nestlings were fed. Male
nestlings were 28.8% heavier than females and were able to reach consistently higher during
feeding bouts; moreover, they begged significantly more often (P = 0.019), were offered
significantly more food (P = 0.011), and were subsequently fed significantly more often (P
= 0.005) than females. Transferred males were offered and received less food than natal
males, while no difference was detected between transferred and natal females. These data,
as the author suggests, seemingly present a paradox, since the larger size of males enables
them to acquire more food more efficiently than their sisters, and yet females are more likely
to survive when food is limited. The author poses several scenarios that help to resolve this
paradox and that explain differences in fledging ratios observed in many sexually dimorphic
species. [Dept. of Zoology, Univ. of Cambridge, Downing St., Cambridge CB2 3E J, United
Kingdom.]--Danny J. Ingold.
6. Effects of nestling age and brood size on nestling care in the Bachman's
Sparrow (Aimophila aestivalis). T. M. Haggerty. 1992. Am. Midi. Nat. 128:115-125.-
The effects of nestling age and brood size on food delivery rates, nestling diet, and nest
attentive time were examined in Bachman's Sparrows in Hot Spring Co., Arkansas, from
1983-1985. Both male and female parents delivered a significantly greater food mass (? <
0.05) to 3-5 and 6-9 day old nestlings than to 0-2 day olds. Nestling age also affected the
number of food items per nestling delivered by females, which was significantly greater (?
< 0.05) for 6-9 day olds than 0-2 day olds. Nestling age had no effect on the number of
food items per trip delivered by either males or females, but 0-2 day old nestlings did receive
significantly fewer total feeding trips (P < 0.05) than 6-9 day olds. Young nestlings (0-2
day olds) received smaller food items than older nestlings, but received significantly more
female attentive time (P < 0.05).
Parents increased food mass delivery (although not significantly), the number of food
items delivered (P < 0.04), and the total number of feeding trips (P < 0.03) to large broods
versus small broods. However, brood size had no effect on the number of food items per
trip delivered by parents of either sex. Males delivered significantly more food to nestlings
than did females (P < 0.01), and delivered a greater percentage of lepidopteran larvae to
0-2 day old nestlings than to older nestlings. Although no difference was detected in the
number of feeding trips made by either sex during the entire period, females spent signif-
icantly more time (P < 0.0004) at the nest than males. [Dept. of Zoology, Univ. of Arkansas,
Fayetteville, AR 72701, USA.]--Danny J. Ingold.
MIGRATION, ORIENTATION, AND HOMING
(see also 16)
7. Calibration of the sun compass by sunset polarized light patterns in a migra-
tory bird. J. B. Phillips and F. R. Moore. 1992. Behar. Ecol. Sociobiol. 31:189-193.-
Nocturnal migrants use a variety of compass systems to obtain directional information,
including the sun, stars, geomagnetic fields, and polarized light. In this experiment, Yellow-
rumped Warblers (Dendroica coronata) were exposed to a polarization axis rotated at different
angles at sunset, in order to determine whether polarized light patterns provide the primary
reference system used to calibrate other compass systems. Warblers exposed to such shifted
axes oriented themselves bimodally along the new axes, confirming the results of an earlier
study, indicating that warblers orient with respect to an artificial light pattern in preference
to the position of the setting sun and the alignment of the geomagnetic field. When artificial
polarization axes were removed (after three nights), warblers continued to exhibit bimodal
orientation coinciding with the former axes. These data suggest that polarized light is indeed
used by Yellow-rumped Warblers to recalibrate one or more of the other compass systems
(most likely the sun compass) during migration. [Dept. of Biology, Indiana Univ., Bloo-
mington, IN 47405, USA.I--Danny J. Ingold.
8. Timing of songbird migration in the St. Croix River Valley, Minnesota, 1984-
1986. K. Winker, D. W. Warner, and A. R. Weisbrod. 1992. Loon 64:131-137.--Birds
were mist-netted in five wooded habitats near Afton, Washington Co., from late April to
late May and mid-August to late September, in order to determine their temporal distri-
butions during migration. The median dates of passage for all 68 captured species (97%
passerines) occurred on 14 May and 31 August. Four species, the Yellow-bellied Flycatcher
(Empidonax flaviventris), Least Flycatcher (E. minimus), Canada Warbler (Wilsonia cana-
densis), and Indigo Bunting (Passerina cyanea), showed a difference between spring and
autumn median dates of 95 days or less, while 18 other species showed a difference of 105
days or less. Of the species that were adequately sampled, 53% spend about 70% of each
year on neotropical wintering grounds and in migration. [Conservation and Research Center,
National Zoological Park, Front Royal, VA 22630, USA.]--Danny J. Ingold.
HABITAT USE AND TERRITORIALITY
(see also 4, 13, 20)
9. Nest-site selection by Golden Eagles in Scotland. J. Watson and R. H. Dennis.
1992. Br. Birds 85:469-481.--A survey of the entire Golden 15agle (Aquila chrysaetos)
breeding population in Great Britain indicated that more than 98% of the pairs resided in
the Scottish highlands and islands. More than 95% of these pairs occupied cliff nests while
the remainder used large trees. The majority of nests were oriented between NW and 15.
Nesting success was not related to distance from public roads, although the more accessible
nests generally produced fewer young. Nest site selection in Scotland was similar to that of
studies from various localities in continental 15urope. [Scottish Natural Heritage, 9 Culduthel
Rd., Inverness 1V2 4AG, Scotland. I--Bruce G. Peterjohn.
10. Surplus territory contenders in male Red-winged Blackbirds: where are the
desperados? D. Shutler and P. J. Weatherhead. 1992. Behav. 15col. Sociobiol. 31:97-106.-
During three breeding seasons in southeastern Ontario (1988-1990), the authors tested
whether payoff asymmetries related to occupancy time, familiarity with neighbors, and
reproductive investment may explain site dominance in Red-winged Blackbirds (Agelaius
phoeniceus). These currencies of payoff asymmetries were tested by removing territorial
male "owners" and allowing floater replacements to claim the vacant territories, after which
owners were released and allowed to compete for their territories. The combined effect of
occupancy time and the number of males removed had no significant effect on a final
replacement's success at retaining territories. In fact, increased occupancy time by final
replacements resulted in quicker usurpation by released owners; moreover, released owners
that spent longer time in captivity were faster at reclaiming their territories. No significant
relationship was detected between the time required for successful owners to reclaim their
territories and the number of neighbors they had. Additionally, the time successful owners
needed to reclaim their territories was unaffected by previous investment in offspring. These
data demonstrate that although only the original owners were successful at reclaiming their
territories, they were only successful about 50% of the time; furthermore, payoff asymmetries
do not appear to explain site dominance in this population of Red-winged Blackbirds. These
results contradict those of a few similar studies, and suggest that territory competition and
the "desperado strategy" (escalated contests by floaters for territory ownership) is of less
importance to male red-wings than are the stern requirements of surviving to adulthood,
locating a vacany, and maintaining the minimum attributes necessary to hold a territory.
[Dept. of Biology, Carleton Univ., Ottawa ON K1S 5B6, Canada.]--Danny J. Ingold.
11. Roost trees used by Pileated Woodpeckers in northeastern Oregon. 15. Bull,
R. Holthausen, and M. Henjum. 1992. J. Wild1. Manage. 56:786-793.--The objectives of
this study were to determine which trees were being selected by Pileated Woodpeckers
(Dryocopus pileatus) for roosting, if roost tree characteristics were similar to that of nest
trees, and to develop roost site management guidelines. Data were collected in 1989 and
1990 in Union, Baker, and Umatilla counties, Oregon, using 27 radio-tagged adults and
nine radio-tagged juveniles.
Adults were always found roosting in cavities at night, usually alone, and averaged seven
roost trees/bird (range = 7-11) over a 3- to 10-month period. Roost trees were typically
large-diameter live or dead trees with a hollow interior, created most often by decay. Forty-
six percent were in live grand fir (Abies grandis), 22% were in ponderosa pine (Pinus
ponderosa), 15% in dead grand fir, and 13% in dead western latch (Larix occidentalis). Conks
of Indian paint fungus (Echinodontium tinctorium) were found on 92% of the roost trees in
grand fir, and 80% of the live roost trees had some type of injury above the roost hole.
Average dbh and height of roost trees were 71 cm and 22 m, respectively. Pileateds excavated
an average 2.7 (range 1-16) entrances to the hollow interior, which had an average diameter
and length of 28 cm and 4.3 m, respectively.
Forest type and successional stage surrounding roost trees significantly differed from
randomly selected trees; roost trees were predominantly surrounded by old growth stands
of grand fir that had little or no logging. Pileated nesting trees differed from roosting trees.
Nesting trees were all dead, had solid interiors and fewer entrances, consisted of 81%
ponderosa pine, 11% western latch, and 8% grand fir, and differed in slope position. However,
successional stage, logging activity, and canopy closure did not differ.
The authors recommend leaving old growth stands of grand fir with at least 60% canopy
closure with no logging or high-grading of old trees. More specific management suggestions
are discussed, including a roost tree formula designed to determine the number of trees to
leave as roosts within each management area. [U.S. Forest Service, 1401 Gekeler Ln., La
Grande, OR 97850, USA.I--Robin J. Densmore.
ECOLOGY
(see also 3, 10, 19)
12. Gopher snake attraction to birds' nests. M. W. Eichholz and W. D. Koenig.
1992. Southwest. Nat. 37:293-298.--Snake predation on Western Bluebirds (Sialia mexi-
cana) in nestboxes was examined in central coastal California during five breeding seasons
to determine whether gopher snakes (Pituophis catenifer) differentially investigate trees
associated with active birds' nests. During the first three seasons, before snakes were captured
with netting placed around the bases of trees, 21% of all nests (and 35.4% of all nest failures)
failed apparently because of gopher snakes. During the last two seasons when snakes were
captured, significantly more snakes were caught at trees with active nests than trees with
inactive nest boxes (P < 0.0S), or at control trees without boxes (P < 0.01). Moreover,
gopher snakes were captured at nest boxes with nestlings (13 of 54) significantly more often
than at nests with eggs (0 of S1, P < 0.05). These data strongly support the notion that
gopher snakes do not randomly climb trees in search of bluebirds; rather, they preferentially
climb trees with nest boxes containing older nestlings. The authors suggest that of the three
possible cues that snakes may use to locate nests (odor, nestling begging calls, adult feeding
visits), odor is the most likely source guiding snakes to trees. This observation is supported
at least weakly by the fact that one gopher snake was captured in a nest box after the young
had fledged. [Hastings Reservation, Univ. of California, 38601 E Carmel Valley Rd., Carmel
Valley, CA 93924, USA.I--Danny J. Ingold.
POPULATION DYNAMICS
(see also 27)
13. Territorial dynamics in an isolated White-Backed Woodpecker (Dendrocopos
[Picoides] leucotos population. A. Carlson and G. Aulen. 1992. Conserr. Biol. 6:450-
454.--White-backed Woodpeckers require old growth and late successional stages of de-
ciduous forest, which may always have been distributed patchily in the taiga forest. Thus,
White-backed Woodpeckers may have a shifting mosaic type of population dynamics that
enable persistence of the metapopulation. To characterize rates of extinction, colonization,
and persistence, one of the three known breeding populations in Sweden was censused
regularly since 1971 to identify locations and number of occupied territories and the gender
and number of adult birds present. A core of high-density territories was surrounded sparsely
by other territories. Upon vacancy, high-density territories were most likely to be recolonized
by one male or a pair; low-density territories were colonized infrequently. Despite a male
biased sex ratio, females often remained unpaired. The observed population did not behave
as predicted by a colonization-extinction equilibrium model. Perhaps population fragmen-
tation and habitat degradation increase the susceptibility of White-backed Woodpeckers to
extinction. [Dept. of Wildlife Ecology, Swedish Univ. of Agricultural Sciences, Box 7002,
S-750 07 Uppsala, Sweden.]--Kristin E. Brugger.
14. Breeding-range and population changes of waders in the former Soviet
Union. P.S. Tomkovich. 1992. Br. Birds 85:344-365.--This study documented changes
in the distributions and abundances of breeding shorebirds in the former Soviet Union,
comparing recent information with published accounts from the 1950s and 1960s. Range
expansions were described for Northern Lapwing (Vanellus vanellus), Greater Golden-Plover
(Pluvialis apricaria), White-tailed Plover (V. leucurus), Black-winged Stilt (Himantopus hi-
mantopus), Terek Sandpiper (Xenus cinereus), Little Whimbrel [Curlew] (Numenius minutus),
Ruff (Philomachus pugnax), and Long-billed Dowitcher (Limnodromus scolopaceus). Both
Collared Pratincole (Glareola pratincola) and Marsh Sandpiper (Tringa stagnatilis) have
expanded in portions of their ranges and declined elsewhere. Declining populations were
evident for Sociable Plover (V. gregarius), Black-winged Pratincole (Glareola nordmanni),
Slender-billed Curlew (N. tenuirostris), and Great Snipe (Gallinago media). The population
declines are probably real, since similar trends have been reported for these four species
elsewhere in their ranges. Whether the range expansions are the result of the availability
of better distributional information or actual population increases could not be established
for the other species. [Dept. of Ornithology, Zoology Museum, Moscow State Univ., Herzen
St. 6, 103009 Moscow, Russia.]--Bruce G. Peterjohn.
15. Dispersal and age of first breeding of Buzzards in central Wales. P. E. Davis
and J. E. Davis. 1992. Br. Birds 85:578-587.--This study of the dispersal of common
Buzzards (Buteo buteo) in western Great Britain was based on data obtained from 234
juveniles banded during a 4oyear period. Most juveniles were relatively sedentary, moving
less than 40 km from their breeding sites. However, a few wandered as far as 200 km from
their nests. Dispersal occurred throughout their first winter, apparently in random directions.
Very little movement occurred after the first winter. One buzzard established a territory
and nested at two years of age, although the average age of first breeding for this population
was 3.5 years. [Wildlife Surveys, Felindre, Aberarth, Aberaeron, Dyfed SA46 0LP, United
Kingdom. I--Bruce G. Peterjohn.
ZOOGEOGRAPHY AND DISTRIBUTION
(see also 14, 31, 32)
16. Patterns of winter distribution and abundance of Lesser Kestrels in Spain.
J. Negro, M. De La Riva, and J. Bustamante. 1991. J. Raptor Res. 25:30-35.--The
objectives of this study were to identify the wintering locations of Lesser Kestrels (Falco
naumanni) in Spain, estimate ages and sex ratios, and determine the phenology of the
migratory subpopulation. Data were collected in 1988 and 1989 in southern Spain.
Thirty-eight colonies were searched, and kestrels were found in the 24 colonies located
along a river valley in farmland areas of central and southwest Andalusia. Average altitude
was significantly lower in colonies with wintering kestrels (172 m, n = 24) than those
without (369 m, n = 14). Sixty percent of the birds that could be sexed were adult males
and 40ø7o were females of unknown age. No juveniles were observed. The number of kestrels
remained stable throughout the winter and ranged from 6 to 88% of the breeding numbers.
Adult males from African wintering grounds were the first to arrive in spring, between 4
and 12 February, while first year males and females arrived during March and April.
Possible factors influencing Lesser Kestrel distribution and abundance are discussed,
including temperature and food availability. [Estacion Biologica de Donana, Pabellon del
Peru, Avda. Maria Luisa s/n, 41013 Sevilla, Spain. I--Robin J. Densmore.
SYSTEMATICS AND PALEONTOLOGY
(see also 22)
17. A new species of PhylloscoIus warbler from central China. P. Alstr3m, U.
Olsson, and P. R. Colston. 1992. Ibis 134:329-334.--This paper describes the Chinese Leaf
Warbler (Sylviidae: Phylloscopus sichuanensis, sp. nov.). The specific nomen refers to the
mountainous Sichuan Province, where the authors first observed this species in April and
June, 1986. At that time at least 17 individuals were encountered in the wild, but no
individual could be trapped (Alstr3m et al. 1990, Bull. Br. Ornithol. Club 110:38-43).
During June 1990, 20 singing males were observed in Wolong Nature Preserve, and for
the two that were paired with females, the nests were located. Three individuals (one male
and two females) were caught, measured, photographed, and blood sampled before being
released. Collection was not permitted. The holotype is a specimen originally labeled as P.
proregulus chloronotus, but now considered to belong to the new species (Zoological Inst.,
Academia Sinica, Beijing China No. 43548, collected in Shanxi Province, 18 May 1962).
In addition to a very thorough description of morphological characteristics, the authors also
provide information on vocalizations, distribution and status, habitat, breeding, and response
to interspecific song playback. [Kungsgaton 3, S-462 33 Vfnersborg, Sweden.]--John A.
Smallwood.
EVOLUTION AND GENETICS
18. Hybridization between a Peregrine Falcon and a Prairie Falcon in the wild.
L. Oliphant. 1991. J. Raptor Res. 25:36-39.--A female Prairie Falcon (Falco mexicanus)
and a male Peregrine Falcon (F. peregrinus) paired and produced two male offspring in
southern Saskatchewan in 1985. Both falcons were observed sharing nest defense and
incubation duties and making food transfers at the eyrie. The offspring were removed, given
to a falconer, and replaced with captive-bred peregrine chicks, which the pair raised suc-
cessfully. The hybrid offspring were larger than typical Prairie Falcons, and after the first
molt showed blue backs, spotted breasts, chestnut napes, and wide malar stripes. The rarity
of interspecific breeding between members of the order Falconiformes in the wild is discussed.
[Dept. of Veterinary Anatomy, Univ. of Saskatchewan, Saskatoon, SK S7N 0W0, Canada.]--
Robin J. Densmore.
PHYSIOLOGY AND DEVELOPMENT
(see also 22, 23, 24)
19. Energetics and adaptations to cold in ptarmigan in winter. K.-A. Stokkan.
1992. Ornis Scand. 23:366-370.--This brief review paper discusses some of the ways in
which ptarmigan deal with severe winter conditions at high latitudes. The birds roost in
snow to escape severe cold and have full crops when they cease feeding activity for the night.
Concomitant with a shift from high protein foods in autumn to low protein, high fiber foods
in winter, the cecae enlarge substantially. Aside from promoting camouflage, the barbules
of the unpigmented feathers of Willow (Lagopus lagopus) and Rock (L. mutus) ptarmigan
contain air-filled cavities that presumably enhance insulation. Svalbard Ptarmigan (L. m.
hyperboreus) take on huge fat stores (35% of body mass) in late autumn as a hedge against
severe winter weather, when feeding is nearly impossible. Using their large pectoral muscles,
ptarmigan shiver in bursts to increase heat production. Keeping their large crop full also
enables continuous digestion that contributes additional heat production. Finally, the birds
reduce their resting metabolic rate in winter such that their lower critical temperature is
close to that which they experience in snow burrows. [Dept. of Arctic Biology, Univ. of
Troms, N-9000 Troms, Norway.]--Jeff Marks.
20. The hormonal control of territorial aggression in tropical birds. R. N. Levin
and J. C. Wingfield. 1992. Ornis Scand. 23:284-291.--The role of testosterone in controlling
territorial aggression has been well documented for male birds during the breeding season.
However, because studies have focused on temperate species in which only the males defend
breeding territories, little is known about the control of territorial aggression during the
nonbreeding season or in females. In contrast to most temperate species, both males and
females of many tropical species defend territories year-round. Accordingly, Levin and
Wingfield studied Bay Wrens (Thryothorus nigricapillus) in Panama and White-browed
Sparrow Weavers (Plocepasser mahali) in Zambia to assess hormonal control of aggression
outside of the breeding season and in females.
In sparrow weavers, circulating levels of testosterone were extremely low, even for males
during the breeding season (maximum level = 0.4 ng/ml). This occurred despite the fact
that testosterone content in sparrow-weaver testes was comparable to that of temperate
White-crowned Sparrows (Zonotrichia leucophrys) and House Sparrows (Passer domesticus).
Moreover, there was no rise in testosterone in males or females that responded aggressively
to song playbacks or to experimental introductions of "replacement" males into flocks. Thus,
there was no direct association of testosterone and territoriality in White-browed Sparrow
Weavers. Similarly, testosterone levels in male Bay Wrens were very low (0.3 ng/ml), and
experimentally induced aggression in both sexes occurred without a concomitant rise in
circulating levels of sex steroids. Moreover, gonadectomized Bay Wrens of both sexes dis-
played normal aggressive responses during natural territorial encounters and during sim-
ulated territorial intrusions. Interestingly, in both species at least one sex exhibited increased
levels of luteinizing hormone (LH) in response to induced aggressiveness.
Levin and Wingfield conclude that testosterone has little effect on aggressiveness, even
during the breeding season. Thus, territorial aggression in these two tropical species either
is independent of control by steroid hormones or is mediated by a non-gonadal hormone
(e.g., LH). Coupled with data from several other tropical species, these results suggest that
the relationship between testosterone and territorial aggression applies only to temperate
species. [Dept. of Biology, Pomona College, Claremont, CA 91711, USA.]--Jeff Marks.
21. Further observations on the timing of skull pneumatization in the Pine
Siskln. R. P. Yunick. 1992. N. Am. Bird Bander 17:93-96.--Eastern New York state
experienced winter invasions of Pine Siskins (Carduelis pinus) in 1975-1976 and 1986-
1987. During these two winters the author was able to capture a total of 1486 siskins and
examine the status of skull pneumatization. Skulls were classified as either completely (SCP)
or incompletely pneumatized (SIP). For the analyses, capture dates were pooled into the
first, middle, and last third of each month, mid-November through early February. The
percentage of SIP birds in each trimonthly sample was regressed over date, and a very tight
linear relationship was revealed (n = 1486, r 2 -- 0.9868, P < 0.00001). A second regression
analysis was performed on only the HY/SY birds, which could be identified by their pointed
rectrices, and again a significant linear relationship was revealed (n = 531, r 2 = 0.8175, P
< 0.00001). For both analyses the author extrapolated a date (1-10 March, the 95%
confidence limit of the x-axis intercept) for completion of skull pneumatization by all siskins.
Interpretation of the first regression is complicated by the fact that a higher mortality
rate for the HY/SY birds (which seems likely) also would decrease the percentage of SIP
birds in the capture samples, affecting the slope negatively. The second analysis, which
included only HY/SY birds, more directly focused on the rate of pneumatization. The
conclusion that all siskins complete pneumatization by 1-10 March should be viewed with
a bit of caution, however, since the regression line was extrapolated well beyond the range
of actual data (the last HY/SY birds were captured in late January) with the implicit
assumption that the true relationship was strictly linear. [1527 Myron St., Schenectady,
NY 12309, USA.]--John A. Smallwood.
MORPHOLOGY AND ANATOMY
22. Structure, function, and variation in the hindlimb muscles of the Margarornis
assemblage (Aves: Passeriformes: Furnariidae.) D. W. Rudge and R. J. Raikow. 1992.
Ann. Carnegie Mus. 61:207-237.--The authors dissected the hindlimb muscles of 20 spec-
imens of five species of furnariids (Margarornis, Premnornis, Premnoplex, Roraimia). These
genera, collectively known as "treerunners" and "barbtails," are found in forest habitats of
central and northern South America, where they characteristically forage over tree surfaces,
occasionally using the tail as a prop. In general, the hindlimb musclcs of these groups are
not as specialized as are those of the woodcreepers. Three hindlimb muscle conditions found
in the group provide further evidence of the monophyly of Passcriformes. This is a wcll-
written, well-illustrated anatomical paper. [Dept. of Biological Sciences, Univ. of Pittsburgh,
Pittsburgh, PA 15260, USA. I--Jerome A. Jackson.
PLUMAGES AND MOLTS
(see also 18, 28)
23. How to molt while fasting in the cold: the metabolic and hormonal adap-
tations of Emperor and King penguins. R. Groscolas and Y. Cherel. 1992. Ornis Scand.
23:328-334.--Emperor (Aptenodytesforsteri) and King (A. patagonica) penguins fast for 32-
35 days while undergoing a complete molt. During this time they lose about 45% of their
body mass, exhausting virtually all of their fat stores and up to 50% of their body protein!
Even more remarkably, some penguins extend their fast for several days to two weeks beyond
the molting period, existing solely on their remaining body protein. Whereas a 30-50% loss
of body protein normally is considered lethal for most birds, some postmolting penguins
survive 60-70% loss of body protein! Plasma concentrations of corticosterone and glucagon
rise abruptly during the last quarter of the fasting phase, suggesting that they play a role
in protein catabolism and gluconeogenesis from amino acids, respectively. Levels of thyroxine
increase during the synthesis of new feathers, suggesting that this hormone triggers the onset
of molt. [Centre d'Ecologie et Physiologie Energfitiques, Centre National de la Recherche
Scientifique, 23 rue Becquerel, 67087 Strasbourg, France. I--Jeff Marks.
24. Adjustments of the prebasic molt schedule in birds. T. P. Hahn, J. Swingle,
J. C. Wingfield, and M. Ramenofsky. 1992. Ornis Scand. 23:314-321 .--This paper reviews
how environmental factors might influence the timing of prebasic molt, including a discussion
of possible endocrine mechanisms based largely on the previous work of Wingfield and his
colleagues.
The authors suggest a scheme in which potential environmental cues are classified ac-
cording to their general function; four such classifications are identified. Cues involved with
initial predictive information determine the broad time window during which molt can occur,
allowing for behavioral, physiological, and hormonal preparation in advance of the molt.
The seasonal change in photoperiod is a typical example. Supplementary information provides
short-term cues that fine tune the initiation and rate of molt to local phenology. Examples
include food availability and temperature, both of which could influence molt either directly
(via neuroendocrine pathways) or indirectly (affecting energy and nutrient balance). Social
cues are classified as synchronizing and integrating information. Although they are important
in synchronizing reproduction between pair members, their influence on molt is not well
understood. Supportive data come from experiments with Song Sparrows (Melospiza melodia)
in which mates of estradiol-implanted females delayed the onset of molt compared with
males mated to females that were given empty implants. The experimental males had elevated
levels of testosterone, a hormone known to delay prebasic molt. Presumably, the prolonged
sexual behavior of implanted females stimulated males to maintain high levels of testosterone
at a time when testosterone normally would be declining in preparation for the prebasic
molt. Lastly, modifying information includes events that alter a process already underway.
For example, an unpredictable crash in food supply could slow or terminate molt.
Although "virtually nothing" is known about the central pathways that control molt,
hormones secreted by the peripheral endocrine glands, particularly thyroxine and testos-
terone, are known to influence the timing of prebasic molt. Evidence suggests that these
hormones act antagonistically, with testosterone inhibiting molt by suppressing the secretion
of thyroxine. This mechanism is understood reasonably well in species that molt after
breeding. Less well understood is how these hormones interact in species that overlap molt
and breeding extensively. The authors end with a plea for additional experimental work,
both in the lab and in the field, that attempts to identify the precise nature and mechanisms
of environmental cues that fine tune the regulation of prebasic molt schedules. [Dept. of
Zoology, Univ. of Washington, Seattle, WA 98195, USA. I--Jeff Marks.
25. Aberrant plumages in a pair of Peregrines in north Scotland. G. G. Bates.
1992. Scott. Birds 16:219.--The author observed a breeding pair of Peregrine Falcons (Falco
peregrinus) at a coastal site in North Sutherland, Scotland, during 1991. Of the three eggs
observed, one was a typical reddish coloration, another significantly paler, and the third
nearly white. The adult female was "unusually dark, almost sooty black without a hint of
the normal grey or blue upperparts ... the underparts were of a dull mid to dark grey
shade, with barring of a slightly darker shade just discernible. The 'moustache' was not
clearly defined on the dark face." The adult male also was unusual, with a dull blue-grey
dorsum and pale, barred underparts. The male had a typical malar stripe, but had a light
patch on the right shoulder.
It was particularly noteworthy that not one but both adults had obviously aberrant
plumage. There was no opportunity to examine plumage characteristics of the young since
the eggs failed to hatch.--[105 Strathy Point, Strathy, Sutherland KW 14 7RY, Scotland. I--
John A. Smallwood.
WILDLIFE MANAGEMENT AND ENVIRONMENTAL QUALITY
(see also 11, 31, 32)
26. Availability and ingestion of lead shot by Mourning Doves (Zenaida ma-
croura) in southeastern New Mexico. T. L. Best, T. E. Garrison, and C. G. Schmitt.
1992. Southwest. Nat. 37:287-292.--Soil samples were taken near a heavily hunted stock-
tank in Eddy County in August (pre-hunting season) and October (post-hunting season),
1987. Sixty-five of 120 (54%) August samples contained one or more lead shot for an
estimated total of 167,593 lead shot/ha in the upper 1.3 cm of soil (X = 1.5 shot/sample),
while 82 of 120 (68%) October samples contained one or more lead shot for a total of
860,185 lead shot/ha (X = 7.7 shot/sample). However, when one October soil sample with
688 shot was excluded, no significant difference was detected in the variances of the August
versus October samples. Examination of gizzards of 420 doves collected in 1985-1987,
revealed that only one dove (0.24%) had definitely ingested lead shot. Nine of 250 livers
(3.6%) contained lead concentrations >7 ppm, and 20 of 250 (8.0%) contained lead con-
centrations -3 ppm. Although the availability of lead shot was enormous, the data suggest
that relatively little was actually ingested by doves. However, the authors caution that low
incidence of lead in doves that were collected may be partially the result of higher mortality
among doves that ingested lead shot. [Dept. of Zoology and Wildlife Science, Auburn Univ.,
AL 36849, USA.I--Danny J. Ingold.
27. The importance of water conservation areas in the Everglades to the en-
dangered Wood Stork (Mycteria americana). G. T. Bancroft, W. Hoffman, R. J. Sawicki,
and J. C. Ogden. 1992. Conserv. Biol. 6:392-398.--The Everglades water conservation
areas (WCAs) appear to be critical foraging habitat for wintering Wood Storks, especially
during drought years when most of south Florida is dry. Comparison of five years of
Everglades colony survey data with projected southeastern United States breeding population
size (modeled from limited survey and demographic data) revealed that large numbers of
nonbreeding storks use the WCAs in late winter. Wood Storks depend on receding water
levels to concentrate prey; in drought years, formerly deep sloughs may be the only feeding
areas available. Changes in the management of these areas could significantly affect the
status of storks throughout the southeastern United States. [National Audubon Society, 115
Indian Mound Tr., Tavernier, FL 33070, USA.]--Kristin E. Brugger.
BOOKS AND MONOGRAPHS
28. On the biology of five species of swifts (Apodidae, Cypseloidinae) in Costa
Rica. M. Marin A. and F. G. Stiles. 1992. Proc. West. Found. Vertebr. Zool. 4:287-351.
Softcover $15.--This monograph includes detailed life histories of the White-collared (Strep-
toproche zonaris), White-chinned (Cypseloides cryptus), Spot-fronted (C. cherriei), Chestnut-
collared (C. rutilus) and Black (Nephoecetes niger) Swifts studied in the canyon of the Rio
Tiribi on the southwestern slope of Volcan Irazu in central Costa Rica between 1984 and
1987. Absolute and relative physical measurements are presented for all species. Sample
sizes are modest for these data, with by far the most data being from the Chestnut-collared
Swift (maximum n = 139) and the least being from the Spot-fronted Swift (maximum n =
11). Detailed data and discussion are presented for foraging ecology, social behavior, flight
characteristics, plumages, molt, vocalizations, nest construction, and various parameters of
breeding biology.
I was truly impressed by the magnitude of effort put into this study and by the depth of
understanding shown of the basic ecology of the region. This monograph is not only a must
for swift biologists, but a gold mine for anyone interested in the natural history of the region,
and a superb model for anyone doing comprehensive life history studies. The monograph
includes figures showing annual variation in rain and temperature (related to nesting phe-
nology), a list of the mosses and liverworts (>30 species; used in nest construction) with
descriptions of their characteristics and habitats, a discussion of other vegetation in the
canyon, and comments on other birds and mammals. A list of birds seen in the area is
available from the authors. [Western Foundation of Vertebrate Zoology, 1100 Glendon
Ave., Los Angeles, CA 90024, USA.]--Jerome A. Jackson.
29. A dictionary of scientific bird names. J. A. Jobling. 1991. Oxford University
Press, Oxford. 272 pp. $29.95, hardcover.--Who among us can read scientific names such
as Upupa epops (for the Hoopoe) or Synthliborarnphus wurnizusurne (for the Japanese or
Crested Murrelet) without wondering what they mean? If the answer to the above question
is "not me, that's for sure," then this book is for you. From aalge to Zosterops, Jobling's
dictionary contains the derivation and meaning of the genus and specific epithet for each of
the extant and recently extinct birds in the world--approximately 8500 entries covering all
living birds described between January 1758 and June 1990. For the nontaxonomist, the
introduction includes information on the codes of nomenclature, grammar and gender, and
a categorical analysis of names (e.g., eponyms, toponyms, and names based on appearance,
habitat, behavior, voice, etc.).
How complete is the treatment, and how accurate are the etymologies? I have looked up
perhaps 300 names of species from throughout the world, and I have yet to be disappointed.
Although I am not qualified to evaluate the etymologies, I suspect that those who are will
find no more than a few points of contention. This scholarly and thoroughly enjoyable work
should be a welcome addition to the library of anyone interested in birds.--Jeff Marks.
30. Sound communication of the Anu Branco. [A comunicao sonora do Anu
Branco.] H. F. Marifio. 1989. Editora Da Univcrsidadc Estadual dc Campinas (UNICAP),
So Paulo, Brazil. 302 pp., appendices with 26 sonograms and 17 maps. (Portuguese.) No
price given, softcovcr.--This publication is a result of a Master in Sciences (Biology) thesis
at the Instituto dc Biologa, Univcrsidadc Estadual dc Campinas, Brazil. The book is an
elaborate description of the lifc history of the Anu Branco [Guira Cuckoo] (Guira guira), a
bird of the family Cuculidac. The main goal of the book was to gain an understanding of
thc spccics communication, by studying its vocalizations, as a mcans to clucidatc thc structurc
of its social organization.
Thc book is organizcd into fivc chaptcrs that follow a thcsis format. In thc first chaptcr
thc author dcscribcs thc vocalizations of thc spccics as an elaboratc systcm of communication
signals. Hc thcn bricfly addrcsscs thc ccological and cnvironmcntal factors that sclcct such
vocalizations, including thc acoustical charactcristics of its habitat and biotic factors. Hc
also dcscribcs how hc dcvclopcd thc dcsign of his study, and thc rational for obscrving wild
and captivc individuals.
In thc sccond chaptcr thc author dcscribcs thc mcthodology he uscd. Hc commcnts on
thc spccics vocal rcpcrtoirc and its biological conscqucnces. Hc continucs by dcscribing thc
facilitics uscd for captivc spccimcns, thc individuals studicd, thc mcthods uscd to rccord
bchavior, and thc making of acoustical rccordings. Hc thcn dcscribcs thc analysis and
classification of vocalizations and thc usc of sonograms.
In Chaptcr 3 hc prcscnts his rcsults. Hc cxamincs in dctail thc functional units of bird
vocalizations, such as notcs and phrascs, and catcgorizcs calls (c.g., calls with dcfinitc rhythms
vcrsus undefincd rhythms). Hc also commcnts on thc bchavioral contcxts of thcsc vocaliza-
tions. Thc antagonistic bchavior among thrcc groups of Anu Branco that hc obscrvcd in thc
wild on thc campus of thc Univcrsidadc Estadual dc Campinas is prcscntcd in dctail. For
the individuals studied in captivity, the social interactions (e.g., hierarchical categories)
among thc flock of fivc to six birds arc dcscribcd bricfly. Also cxamincd arc scvcral catcgorics
of calls, such as rccognition calls uscd in congrcgations, hostilc calls, and calls associatcd
with brccding bchavior.
Thc discussion and conclusions arc prcscnted in Chaptcr 4. First, thc author summarizcs
thc various vocalizations and thcir functions. Thc author thcn prcscnts a discussion on how
communication signals arc affcctcd by thc acoustical charactcristics of thc cnvironmcnt. Thc
propagation efficiency from a source of sound (the bird) depends not only on the sound
cncrgy produccd but also on ccrtain atmosphcric gradicnts. From thc structural point of
vicw, calls arc organizcd tcmporally, and thcy acquirc biological connotations. Thc author
suggcsts that animals which producc multiplc and spccializcd signals tcnd to form vcry
complcx socictics. Finally, hc discusscs thc charactcristics of social organization in thc Anu
Branco, including fccding bchavior and social aggrcgations in roosts. Thc final chaptcr is
the bibliography.
Although thc study was dcscriptivc in naturc, this volumc prcscnts an cxtraordinary
compilation of bchavioral data. I think thc book would havc bccn morc uscful if social
behavior had been compared quantitatively between the captive and wild individuals observed
during his study; statistical analyses are almost totally lacking. Nevertheless, the book could
be an excellent source of data for those specializing in avian ethology and bioacoustics.--
Eduardo Ifiigo-Elias.
31. Proceedings of the first Mesoamerican workshop on the conservation and
management of macaws. J. Clinton-Eitniear, ed. 1991. Misc. Publication No. 1, Center
for the Study of Tropical Birds, Inc., 218 Conway Drive, San Antonio, Texas 78209-1716.
73 pp. No price given, softcover.--This publication is based on a symposium organized by
the Center for the Study of Tropical Birds, Inc., held in Tegucigalpa City, Honduras, 4-
7 January, 1991.
Jack Clinton-Eitniear, director of the CSTB, organized this macaw symposium and edited
the proceedings. This volume includes 10 papers on the natural history and captive breeding
biology of the species of macaws that occur in Central America. In addition, three papers
present information on the biology and ecology of several macaws in Venezuela, Brazil, and
southern Peru, even though these countries are not included within the focus region of the
symposium. A total of eight Ara and Anodorhynchus species are discussed in the proceedings.
Two papers focus on the conservation and status of the Scarlet Macaw (Ara macao) in
Belize, and a third paper deals with the status in Guatemala. Two more papers present
information on the species in Honduras; one on its status and the other on the use of macaw
designs in pre-Columbian Art. A sixth paper describes the distribution and conservation
efforts related to two species, the Scarlet Macaw and the Great Green Macaw (A. ambigua)
in Nicaragua. Next are two papers on the Scarlet Macaw in Costa Rica; the first concentrates
on its ecology and management while and the second is an economic analysis of the role of
ecotourism in the conservation of this species. Another paper covers the status of three
macaws, the Green-winged Macaw [Red and Green Macaw] (A. chloroptera), the Military
Macaw (A. militaris), and the Chestnut-fronted Macaw (A. severa) in Venezuela. The
potential for sustainable use of Scarlet Macaws, Red and Green Macaws, and Blue and
Yellow Macaws (A. ararauna) in southern Peru is discussed in another paper. Conservation
of the Lear's Macaw (Anodorhynchus leari) in Brazil is the focus of another paper. Finally,
two papers discuss captive breeding biology of six species: Blue and Yellow Macaws, Scarlet
Macaws, Military Macaws, Buffon's [Great Green] Macaws, Green-winged Macaws, and
Hyacinth Macaws (Anodorhynchus hyacinthinus ).
Most of the information presented in this monograph is related to the natural history of
macaws, including geographical distribution, food habits, current status, and conservation
problems within the region. The majority of the papers present data almost exclusively on
one species, the Scarlet Macaw. This information is very valuable to the design of future
research efforts to protect and manage the species. Nevertheless, very few quantitative and
comparative data are presented in these papers. This book's contribution to neotropical
ornithology would have been enhanced if greater attention had been paid to the editorial
work, including better graphics and tables, and better documentation (e.g., literature cita-
tions). The last two papers on captive breeding contain numerous tables of important
biological information for six macaw species, but they lack completely any references.
My main criticism of this publication relates to the last section, a set of 25 utilitarian
resolutions and recommendations. These are grouped by topic, including ecotourism, ranch-
ing and captive breeding, nest boxes/habitat management, education, introduction and
release, and trade/regulation and law enforcement. In my opinion, there is far too little
emphasis on the basic efforts required to conserve this species in a natural state in the wild.
Much more needs to be done simply to understand the biology and ecology of these species
and their functional role in the neotropics.--Eduardo Ifiigo-Elias.
32. Putting biodiversity on the map: priority areas for global conservation. C.
J. Bibby, N.J. Collar, M. J. Crosby, M. F. Heath, Ch. Imboden, T. H. Johnson, A. J.
Long, A. J. Stattersfield, and S. J. Thirgood. 1992. International Council for Bird Pres-
ervation, Cambridge, United Kingdom. 90 pp., 36 figures, 22 tables, numerous color pho-
tographs, five appendices. $23.50, softcover.--Bibby et al. have done a splendid job in
compiling and editing an enormous collection of biological and ecological data on the dis-
tribution of biological diversity around the world. This book also has an excellent design
with impressive color graphics that clearly illustrate points being made, and beautiful color
pictures that enhance the presentation.
The first section of the book, the introduction, deals with the concept of biodiversity,
defined as "the total variety of life on earth." The authors also examine why it is important
to study and conserve biodiversity, not only from the economic point of view but from an
ethical one as well. They also explore how and where to conserve biodiversity. They present
data which illustrate the uneven spatial distribution of biodiversity. Seventy percent of the
world's threatened birds are located in just 12 countries. These countries are located mainly
in the tropics and are known as "megadiversity countries." The authors also present evidence
as to why birds are good indicators of biodiversity. Of the many different life forms on our
planet, birds are among the most well studied.
In the second section of the book the authors describe the different methods followed by
the biodiversity project to compile all this information. The authors developed a computerized
database list of over 2,600 birds. This information was compiled from distributional data
in maps and published references, as well as through consultation with local experts in each
country or region. This list includes data such as species, common names, habitat, altitude,
status, and codes for the Endemic Bird Areas (EBAs, see below). Data from range maps
for each species were digitized into a Geographical Information System (GIS). The primary
goal of this analysis was to identify those areas with concentrations of restricted-range
species. They considered areas of primary importance those where two or more species of
restricted distribution occur; these areas are known as Endemic Bird Areas (EBAs).
In the third section a global overview of avian data is presented. The authors found that
more than 25% of all land birds (n = 2,609) have breeding distributions less than 50,000
km 2. Bird families such as Alcedinidae and Zosteropidae have more than 70% of their species
exhibiting significantly restricted ranges. Countries such as Mexico and five other South
American nations have over 100 restricted-range birds occurring within their borders. The
five countries with the highest number of EBAs are Indonesia (24), Peru (18), Brazil (17),
Mexico (14), and Colombia (14). Comparisons are made between island and continental
EBAs, and the authors discuss the relationship between numbers of restricted-range bird
species and the size of EBAs. Countries such as Indonesia, Brazil, Colombia, Peru, and
Ecuador have the highest numbers of threatened restricted-range bird species. More than
60% of all threatened restricted-range species are threatened because of habitat destruction.
In the fourth section on regional accounts of EBAs, the authors identify six main regions:
North and Middle America (including the Caribbean islands), South America, Africa,
Europe and the Middle East, Asia, South-East Asian Islands (including New Guinea and
Australia), and Pacific Islands. The areas with the greatest and lowest restricted-range bird
species are South America with 27% (709 species) and Asia with 8% (201). The areas with
the most and least EBAs are South America with 26% and Asia with 12%.
The fifth section focuses on patterns of endemism in animals and plants. Here the authors
look for other patterns of endemism in the flora and fauna of the six regions. Within the
North and Middle America and South America regions they found a similar pattern of
endemism with reptiles and amphibians, insects, butterflies, and trees.
In the sixth section the authors evaluate the priorities for action to ensure the survival of
at least 20% of all land birds by actions on just 2% of the earth's land area. The most
obvious way to evaluate EBAs would be in terms of the numbers of restricted-range bird
species they contain. These EBAs have been graded according to the taxonomic uniqueness
of all the restricted-range bird species occurring in them. These EBAs also have been classified
on the basis of existing knowledge of endemic plants and other animals.
In the seventh section the authors present the conclusions. Two hundred and twenty-one
EBAs have been identified where 26% of all land birds are restricted. Most of these areas
are also important for other organisms such as plants and invertebrates. The future of all
these EBAs is critical for global biodiversity conservation. In the appendices the authors
present several tables with data covering EBA data by region, comparison of endemism
between birds and other animals and plants, and priority listings of EBAs.
This brief volume is an excellent and highly original effort that will make ornithologists,
conservationists, and decision makers aware of the broader context of biodiversity, and the
role birds play in conservation biology. I highly recommend this book.--Eduardo Ifiigo-
Elias.