My
research incorporates conservation biology, and behavioral and population
ecology.Most of my work has been
with birds, although my students have studied aquatic invertebrates, plants,
herps, and mammals.This work has
been conducted in terrestrial, wetland, and near shore marine ecosystems in the
U.S. (California, Connecticut, Florida, Illinois, Ohio, and Michigan), the
Caribbean (Cuba and Puerto Rico) and South America (Guyana and Venezuela).
The interaction of animal
ecology and natural resource management has been a common denominator of much of
my work.My conservation biology
publications have emphasized the management and recovery of endangered species,
the use of models for analyzing risks of extinction for threatened populations,
and the potential for conservation gains and losses from sustainable harvesting
and international trade.In ecology, my work has centered on understanding why
particular parental care strategies occur, patterns of demography and population
dynamics, and how diet specialization is maintained.
I approach research by
combining intensive field studies based on natural history and quantitative
sampling with field experiments and modeling, and expect the same of my graduate
students.A dominant theme in my
research has been to determine the influence of environmental variation on
behavior, to link behavior to population ecology, and to use this knowledge in
conservation.I have made
contributions to both applied conservation biology and basic ecology because I
chose systems to study that were amenable to both kinds of research, and I
conducted studies that both tested theories and yielded data that was relevant
to management or policy options.This
approach formed the basis for a review I published on how behavioral ecologists
can make their research programs more useful for conservation (Beissinger 1997)
and is illustrated below by my recent work on parrotlets.
My current studies of Green-rumped
Parrotlets in Venezuela have important implications for both conservation
biology and behavioral ecology, and have been supported by two grants from the
National Science Foundation.One award was to investigate the functional significance of
the early onset of incubation behavior leading to hatching asynchrony in this
small parrot, while the other was collaborative research to evaluate genetic and
demographic approaches to estimate population viability.The Green-rumped Parrotlet is an ideal species for studies of hatching
asynchrony and demography because it lays unusually large clutches (x = 7 eggs),
begins incubation on the first egg so chicks in a brood hatch extremely
asynchronously (up to two weeks apart), nests in artificial boxes facilitating
clutch and brood manipulations, and is easily captured for banding (Beissinger
& Waltman 1991).
Hatching asynchrony can be
considered one of the long-standing puzzles in avian behavioral ecology.Birds are unusual, compared to other vertebrates, in having some control
over birthing patterns but often select a pattern that leads to mortality of
last hatched young.As we have
pointed out in an extensive review paper, no less than 17 hypotheses have been
proposed to explain why birds initiate incubation before a clutch has been
completed (Stoleson & Beissinger 1995).Most previous work concentrated on demonstrating the adaptive
significance of the resulting hatching patterns (and the brood reduction it
causes due to age differences among nestmates), while ignoring the behaviors and
events that occur before incubation is initiated.When birds hesitate for several days before initiating incubation, they
leave their eggs unattended and susceptible to fluctuating temperatures and
predators.We measured an
exhaustive set of fitness correlates at experimental synchronously and
asynchronously hatching nests, and could find no evidence that asynchrony
benefited hatching patterns in one of the most comprehensive analyses of the
adaptive significance of brood reduction (Stoleson & Beissinger 1997a).Using doubly labeled water, we also found no differences in the energy
expenditures of parents that reared synchronous and asynchronous broods (Siegel
et al. 1999).
Finding little evidence that
asynchrony directly benefited young or adults after hatching, we then conducted
experiments to examine the consequences of not caring for eggs during laying.Field experiments tested the ability of newly laid eggs to survive when
exposed to ambient air temperatures (Stoleson & Beissinger 1999).Parrotlet eggs were exposed for only several days to warm air
temperatures before their hatchability started to decline rapidly.A second experiment examined the consequences of not guarding nests (Beissinger
et al. 1998).Unguarded parrotlet
nests had a high rate of egg destruction by nonbreeding male-female and
male-male parrotlet pairs due in part to limited breeding opportunities (Beissinger
1996).
These exciting findings have suggested a new avenue
for understanding the significance of hatching asynchrony — the idea that
unincubated bird eggs have a shelf life that may vary with environmental
conditions.It was an important
theme at a symposium I co-organized at the International Ornithological Congress
in South Africa in 1998.I am now pursing this idea on two fronts.First, I have begun to use models to examine how the onset of incubation
affects the potential for interactions among egg viability, predation and brood
reduction (Beissinger 1999).Second,
I designed a set of critical experiments to determine if and how temperature
constrains viability of unincubated eggs using a climate gradient along the
slope of a mountain in Puerto Rico with another bird, the Pearly-eyed Thrasher.This project was funded by NSF, and work was begun in February
2000 in collaboration with a postdoctoral student, Dr. Mark Cook. The
thrasher project incorporates studies of the temperature and humidity effects
with studies of microbiology to determine which factors critically affect the
shelf life of eggs.
Our parrotlet work in Venezuela is providing the first
detailed study of a New World parrot, having banded over 5,000 birds and tracked
over 1500 nesting attempts during the past 14 years (Waltman & Beissinger
1992; Curlee & Beissinger 1995; Sandercock et al. 2000).It is also one of the longest studies of a South American bird, now in
its 15th year, and provides important comparisons with well-studied
temperate counterparts.Dr. Brett
Sandercock, a former postdoc of mine, and I are in the midst of analyses of
demography and population dynamics of parrotlets.We used mark-recapture statistical models to estimate
survival for 1334 adults that were color-banded and released during the first
decade of study (Sandercock et al. 2000).Both
sexes had low annual local survival rates, similar to temperate birds.However, this conclusion obscured substantial heterogeneity in survival
caused by a large number of nonbreeding males.Using dynamic multi-state models, we found that survival was higher for
breeders than nonbreeders, and higher than similar temperate species.Estimates were not biased by dispersal because adults showed strong
site-fidelity.This work has
important implications for understanding latitudinal changes in survival and
life history of birds.
The next step in my research
program is to integrate behavior into a holistic understanding of parrotlet
mating and social systems, and population dynamics.I am pursing this through: (1) collaborative studies of the genetic
mating system including microsatellite DNA analyses of parentage with Dr. Colin
Hughes at the Universit6y of Miami and his former doctoral student, Dr. Rebecca Melland
(Hughes et al. 1998); (2) detailed behavioral studies of the social system of
nonbreeding parrotlets being pursued by one of my current Ph.D. students, Eric
Punkay; (3) continued long-term analyses of behavioral ecology conducted by my
current postdoctoral student, Dr. Amber Budden,;and (4) analyses
of the temporal and spatial dynamics of parrotlet populations using matrix
population models that incorporate the mating and social structure of the
population.
Several applications for
conservation have grown directly from our parrotlet studies.First, parrots are one of most threatened groups of birds, due to
harvesting for the pet trade and habitat destruction.Biological and conservation information was so lacking for parrots that I
co-organized a symposium on this topic for the American Ornithologists' Union.The resulting book (Beissinger & Snyder 1992) is not only an
important reference for parrots, but serves as a benchmark evaluation for a
variety of techniques used in conservation biology: reintroduction, captive
breeding, ecotourism, sustainable harvesting, and education.Second, nestbox schemes patterned after our work in Venezuela may offer a
way to both conserve habitats and manage parrots in a sustainable manner.My project in Venezuela developed a conservative model for sustainably
harvesting parrots (Beissinger & Bucher 1992, Stoleson & Beissinger
1997b).A portion of young could be
harvested without impacting population size by providing nest boxes, since many
parrots are limited by nest site availability.In addition, young can be sustainably harvested by taking last-hatched
chicks that typically die due to sibling competition caused by hatching
asynchrony.We have also evaluated
the accuracy and precision of methods for monitoring parrot populations in one
of the few bird studies that have compared survey techniques with a reference
population (Casagrande & Beissinger 1997).Our studies have provided the basis for sustainable harvesting provisions
in the Wild Bird Conservation Act of 1992, for which I testified twice before
the U.S. Congress (Beissinger 1992).The development of biological principles to guide the
international trade, as part of the work of a subcommittee of the American
Ornithologists’ Union that I chaired (Beissinger et al. 1991), helped to
strengthen the act. I summarize this work by addressing potentials, principles and
practices of sustainable use of birds at a symposium of the London Zoological Society (Beissinger
2001).
Population viability analysis (PVA)
uses models to estimate risks of extinction and has become an important tool in
conservation decisions.Yet, PVA is relatively untested and is still far from
reaching its potential.In a widely
read paper (Beissinger and Westphal 1998), I summarized various types of PVA
models and examined the strengths, weaknesses and optimal uses of PVA.The paper catalyzed a highly successful international conference I
co-organized with Dr. Dale McCullough, Leopold Chair in Wildlife Ecology at U.C.
Berkeley, in San Diego, California in March 1999 that was attended by 350
participants (Mann and Plummer 1999).
We edited a book from the conference that was published by University of
Chicago Press (Beissinger and McCullough 2002).
I have tried creatively to use
demographic models and PVA to make management decisions for the recovery of
endangered species.I formalized an
approach to modeling extinction in periodic environments and applied it to water
management problems affecting the Snail Kite in the Everglades (Beissinger
1995a).To model the likelihood of
extinction, I needed a stochastic population viability model that did not
project demographic rates randomly, because Everglades water levels have
long-term periodicity of droughts and floods (Beissinger 1986).I developed a method using the cyclic occurrence of environmental states
that may also be applied to other systems.This is one of the few PVAs that calibrates population projections
against census data.
I have also developed
demographic models to evaluate management strategies for endangered birds,
orchids and sea turtles.I
conducted demographic analyses and developed a simple model while serving on a
National Research Council Committee to develop a plan to recover the highly
endangered Mariana Crow on the island of Guam (NRC 1996).I also evaluated the demographic conditions when relocating loggerhead
sea turtle nests from beaches to protected sites is a useful strategy (Grand
& Beissinger 1997).Recent work (Meretsky et al. 2000) examined levels of
mortality that are permissible for the California Condor reintroduction effort.One of my former graduate students, Rich Shefferson, adapted mark-recapture
models to estimate dormancy in a threatened orchid (Shefferson et al. 2001).While serving on the Marbled Murrelet Recovery Team, I
developed a model using the ratio of juveniles to after-hatch-year birds and
survivorship estimated from allometric relationships (Beissinger 1995b, USFWS
1995) to estimate rates of population decline for Marbled Murrelets in the
Pacific Northwest.As a result of
my experiences, I teach the small population biology portion of a training
course in scientific principles of endangered species management to USFWS
biologists.
My graduate students and I have
been conducting field studies of an endangered seabird, the Marbled Murrelet, in
central California.This bird is
extremely difficult to study because its nests are hard to find in old growth
forests 35-75 m above the ground and individuals are difficult to catch and band
while spending most of their life at sea.Until recently, very little was known about this bird except
that it was threatened by the cutting of old growth forests and oil spills and
had declined in numbers throughout the Pacific Northwest
The first goal of our research
was to develop robust methods to estimate murrelet population trends.We adapted line-transect sampling to avian surveys at sea (Becker et al.
1997).This resulted in a new
sampling method for murrelets, spawned a workshop that I ran for the U.S. Fish
and Wildlife Service to train at-sea researchers in the techniques, and yielded
a research contract to test various sampling designs for a regional monitoring
program in the Pacific Northwest (Beissinger et al. 1999).Ben Becker, a recent Ph.D. graduate from my lab and now a research
scientist with the National Park Service, developed a detailed
analysis of the habitat use and factors affecting the distribution of murrelets
at sea as part of his dissertation.He
also analyzed the stable isotope contents of murrelet feathers in order to
determine the diet composition of these birds.
The second objective of our
work is to determine the causes of the murrelet population decline.Zach Peery, a doctoral student in my lab, and I began a
mark-recapture study and a radio-telemetry study in 1999 that should yield demographic
and behavioral clues to determine whether murrelets are declining because of
high rates of nest failure or because many individuals fail to nest.We radio-tagged a total of 48 murrelets in April and May 2000 and 2001, and followed their
movements and survival closely. Telemetry
has allowed us to find nests and to estimate the proportion of birds
nesting and their nesting success.
The Song Sparrows of San
Francisco Bay offers a unique glimpse of evolutionary biology in a threatened
ecosystem close to Berkeley.Three
subspecies of Song Sparrow are found in restricted, nonoverlapping portions of
the bay wetlands at densities an order of magnitude greater than neighboring
upland subspecies.Letitia Grenier
is a doctoral student in my lab who is studying the behavior and ecology of
these birds in order to understand the factors that promote the causes and
consequences of such high densities.Her work includes detailed studies of the territorial and
social system, DNA analyses of parentage, and analyses of food habits using
stable isotopes. Dr. Cully Nordby, a postdoctoral student in
my lab who is a Smith Postdoctoral Conservation Fellow sponsored by the Nature
Conservancy, is working on the effects of an introduced plant on the nesting biology
and competitive interactions of these sparrows and marsh wrens.
My dissertation and
postdoctoral field studies of the Snail Kite in Florida and South America from
1977-1989 yielded data crucial to the conservation of this endangered hawk,
including the discovery of key biological processes relevant to its persistence
in the Everglades ecosystem.Four
papers (Beissinger 1986, Snyder al. 1989, Takekawa & Beissinger 1989,
Beissinger 1995a) offer valuable data on kite demography, and show the effects
of Everglades water management through detailed field studies and analysis of
long-term data on water level and demography.I also examined the problems of protecting small, temporarily-used
wetlands under the Endangered Species Act, which are critical to the kite's
survival during drought and have been rapidly developed.
While conducting the above
work, I also studied how differences in reproductive investments and demography
between the sexes affected the mating system and parental investments of these
hawks.I discovered with Dr. Noel
Snyder that the Snail Kite has an extremely unusual mating system: if snails are
abundant, either parent may desert its
mate about half-way through the period of parental care and may find a new mate
to begin another nesting attempt.My
early work in Florida elucidated the proximate characteristics of this mating
system, and is often cited as one of the first detailed studies of mate
desertion by either sex in birds (Beissinger & Snyder 1987).It also provided strong tests of parental investment theory by relating
expenditure of reproductive investments to the sex of the deserting parent at
kite nests (Beissinger 1987a,b).Later
experiments in Venezuela tested a heuristic model that related both brood size
and food demand to a monoparental threshold for desertion in one of the few
papers to manipulate the occurrence of mate desertion (Beissinger 1990a).In an important paper (Beissinger 1986), I modeled environmental
predictability (Beissinger & Gibbs 1993), showed how ecosystem management
affected both short- and long-term environmental cycles, and illustrated how
environmental unpredictability in the form of fluctuating water levels could
select for mate desertion.To
understand mate desertion from a comparative perspective, I conducted the only
study in the past 40 years on the biology of the Slender-billed Kite (Beissinger
et al. 1988), a little known South American congener of the Snail Kite that also
feeds primarily on snails.Interestingly,
unlike the colonial, marsh-nesting Snail Kite, the territorial Slender-billed
Kite nests solitarily in flooded forests and did not appear to practice mate
desertion.
Vertebrates that eat few kinds of
foods are extremely rare.My
earliest studies of the Snail Kite in Guyana were the first to quantify hunting
behavior, snail choice and energetics of this highly specialized forager (Beissinger
1983).Later I documented the
ecological circumstances and consequences for kites of taking nonsnail prey -
mainly small turtles in Florida and crabs in Venezuela (Beissinger 1990b).Behavioral experiments conducted with free-flying birds in Venezuela
showed that kites preferred snails to crabs, even when snails were much less
profitable (Beissinger et al. 1994).This
work suggested a role for behavioral conservatism, in the form of risk-averse
foraging and neophobia, in maintaining diet specialization.
A final dimension of my work
has been to help the newly emerging science of conservation biology develop as a
discipline that can offer “tools” to assist in the protection, restoration
and sustainable use of biological diversity.In a widely read paper that has had a large influence on endangered
species recovery strategies, a diverse group of colleagues and I analyzed the
use of captive breeding as a conservation tool (Snyder et al. 1996, 1997a,b).I also developed an approach to set conservation priorities
among ecosystems that uses differences in the distributions of threatened and
nonthreatened species as indicators of ecosystem integrity, and the distribution
of parks and reserves and nonprotected lands as indicators of ecosystem
protection (Beissinger et al. 1996).We
applied it to an analysis of the biomes and avifauna of South America, showing
how the most diverse biomes (tropical humid forests and montane) may not be as
threatened as less diverse but poorly protected biomes (tropical dry forests and
subtropical rainforests).Finally, I have worked with a group of economists to examine
why economics matters for endangered species protection (Shogren et al. 1999),
and with a committee of ornithologists to evaluate a widely-used protocol for
prioritizing species for conservation (Beissinger et al. 2000).
Becker, B. H., S. R.
Beissinger, and H. Carter. 1997.At-sea
density monitoring of Marbled Murrelets in central California: methodological
considerations.Condor
99:743-755.
Beissinger, S. R.1983.Hunting behavior, prey selection and energetics of Snail
Kites in Guyana: consumer choice by a specialist.Auk 100:84-92.
Beissinger, S. R.1986.Demography, environmental uncertainty, and the evolution of mate
desertion in the Snail Kite.Ecology
68:1445-1459.
Beissinger, S. R.1987a.Mate desertion and reproductive effort in the Snail Kite.Animal Behaviour 35:1504-1519.
Beissinger,
S. R.1987b.Anisogamy overcome: female strategies in Snail Kites.American Naturalist
129:486-500.
Beissinger, S. R.1990a. Experimental brood manipulations and the monoparental threshold in
Snail Kites.American
Naturalist 136:20-38.
Beissinger,
S. R.1990b.Alternative foods of a diet specialist, the Snail Kite.Auk 107:327-333.
Beissinger, S. R.1992.Statement before the joint hearing of the U.S. House of
Representatives Subcommittee on fisheries and Wildlife Conservation and the
Environment of the Committee on Merchant Marine and Fisheries, and the
Subcommittee on Trade of the Committee on Ways and Means.Congressional Record Serial 102-84, Pp. 16-18 and 110-119.
Beissinger, S. R.1995a.
Modeling extinction in periodic
environments: Everglades water levels and Snail Kite population viability.Ecological Applications 5:618-631.
Beissinger, S. R.1995b.Population trends of the Marbled Murrelet projected from demographic
analyses.Pages 385-393 in Ecology
and Conservation of the Marbled Murrelet (C. J. Ralph, G. L. Hunt, Jr., M.
G. Raphael, and J. F. Piatt, Eds.).General
Technical Report PSW-GTR-152, Pacific Southwest Research Station, U.S.D.A.
Forest Service, Albany, CA.
Beissinger, S. R.1996.On the limited breeding opportunities hypothesis for avian
clutch size.American Naturalist 147:655-658.
Beissinger, S. R.1997.Integrating behavior into conservation biology: potentials
and limitations.Pages 23-47 in
Behavioral Approaches to Conservation in the Wild (J. R. Clemmons and R.
Buchholtz, Eds.).Cambridge University Press, Cambridge, U.K.
Beissinger,
S. R.1999.Interaction of egg viability, brood reduction and nest
failure on the onset of incubation.Pages
638-646 in Proceedings of the 22nd
International Ornithological Congress (N.J. Adams, & R.H.Slotow, Eds.).BirdLife South Africa, Durban: Johannesburg, South Africa.
Beissinger, S. R.In press.Trade in Live Wild Birds: Potentials, Principles and
Practices of Sustainable Use.In
Conservation of Exploited Species (J. D. Reynolds, G. M. Mace, K. H. Redford,
and J. G. Robinson, Eds.).Cambridge
University Press.
Beissinger, S. R. and
E. H. Bucher.1992.Can parrots be conserved through sustainable harvesting? BioScience 42:164-173.
Beissinger, S. R. and
J. P. Gibbs.1993.Are variable environments stochastic? A review of methods to quantify
environmental predictability.Pages
132-146 in Adaptation in Stochastic Environments (J. Yoshimura and C. W.
Clark, Eds.).Lecture Notes on
Biomathematics Springer-Verlag, Berlin.
Beissinger, S. R. and D. R. McCullough (Editors).
2002.Population
Viability Analysis.University of
Chicago Press, Chicago, IL.
Beissinger, S. R. and
N. F. R. Snyder.1987.Mate desertion in the Snail Kite.Animal
Behaviour 35:477-487.
Beissinger, S. R. and N. F. R. Snyder (Editors).1992.New World Parrots in
Crisis: Solutions from Conservation Biology.Smithsonian Institution Press, Washington, D.C.
Beissinger, S. R. and
J. R. Waltman.1991.Extraordinary clutch size and hatching asynchrony of a neotropical
parrot.Auk
108:863-871.
Beissinger, S. R., and M. I. Westphal.1998.On the use of
demographic models of population viability analysis in endangered species
management.Journal
of Wildlife Management 62:821-841.
Beissinger, S. R., B.
T. Thomas, and S. D. Strahl.1988.Vocalizations, food habits, and nesting biology of the Slender-billed
Kite with comparisons to the Snail Kite.Wilson Bulletin 100:604-616.
Beissinger, S. R., N.
F. R. Snyder, S. R. Derrickson, F. C. James, and S. M. Lanyon.1991.International trade in
live exotic birds creates a vast movement that must be halted.Auk 108:982-984.
Beissinger, S. R., T.
J. Donnay, and R. Walton.1994.Experimental analysis of diet specialization in the Snail Kite: the role
of behavioral conservatism.Oecologia 100:54-65.
Beissinger, S. R., E.
C. Steadman, T. Wohlgenant, G. Blate, and S. Zack.1996.Null models for
assessing ecosystem conservation priorities: threatened birds as titers of
threatened ecosystems.Conservation
Biology 10:1343-1352.
Beissinger, S. R., S.
Tygielski, and B. Elderd.1998.Social constraints on the onset of incubation in a neotropical parrot: a
nest box addition experiment.Animal
Behaviour 55:21-32.
Beissinger,
S. R., B. H. Becker, L. Rachowicz and A. Hubbard.1999.Testing and designing
methods for developing an at-sea monitoring strategy for the Marbled Murrelet.Unpublished Report to the U.S. Fish and Wildlife Service.99 pages.
Beissinger, S. R., J. M. Reed, J. M. Wunderle, Jr., S. K.
Robinson, and D. M. Finch.2000.Report of the AOU Conservation Committee on the Partners in Flight
species prioritization plan.Auk
117: 549-561.
Casagrande, D. G.,
and S. R. Beissinger.1997.Evaluation of four methods for estimating parrot population size.Condor 99:445-457.
Curlee, A. P., and S.
R. Beissinger.1995.Experimental analysis of mass change in female green-rumped parrotlets (Forpus
passerinus): the role of male cooperation.Behavioral Ecology 6:192-198.
Grand, J. and S. R. Beissinger.1997.When relocation of
loggerhead sea turtle (Caretta caretta) nests becomes a useful strategy.Journal of Herpetology 31:428-434.
Hughes, C. R., R. R. Melland, and S. R. Beissinger.1998.Polymorphic
trinucleotide microsattelite loci for a neotropical parrot, the green-rumped
parrotlet, Forpus passerinus.Molecular Ecology 7:1247-1248.
Mann, C. C. and M. L. Plummer.1999.A species’ fate by
the numbers.Science
284:36-37.
Meretsky, V. J., N. F. R. Snyder, S. R. Beissinger, D. A.
Clendenen, and J. W. Wiley.In
press.Demography of the California
Condor: implications for restablishment.Conservation
Biology.
National Research Council (NRC).1996.The Scientific Basis
for the Preservation of the Mariana Crow.National
Academy of Sciences, Washington D.C.91
pp.
Sandercock, B. K., S. R. Beissinger, S. H. Stoleson, R. R.
Melland, and C. R. Hughes.2000.Survival rates of a Neotropical parrot: implications for latitudinal
comparisons of avian demography.Ecology 81:1351-1370.
Shefferson, R. P., B. K. Sandercock, J. Proper, and S. R.
Beissinger. 2001. Estimating dormancy and survival of a rare herbaceous perennial using
mark-recapture models.Ecology82:145-156.
Shogren, J. F., J. Tschirart, T. Anderson, A. W. Ando, S. R.
Beissinger, D. Brookshire, G. M. Brown, Jr., D. Coursey, R. Innes, S. M. Meyer,
and S. Polasky.1999.Why economics matters for endangered species protection and the ESA.Conservation Biology.13:1257-1261.
Siegel, R. B., W. W. Weathers, and S. R. Beissinger.1999.Hatching asynchrony
reduces the duration, not the magnitude, of peak load in breeding green-rumped
parrotlets (Forpus passerinus).Behavioral Ecology and Sociobiology
45:444-450.
Snyder, N. F. R.,
S. R. Beissinger, and R. Chandler.1989.Reproduction and demography of the Florida Everglade (Snail) Kite.Condor 91:300-316.
Snyder, N. F. R.,
S. R. Derrickson, S. R. Beissinger, J. W. Wiley, T. B. Smith, W. D. Toone and B.
Miller.1996.Limitations of captive breeding in endangered species recovery.Conservation Biology 10:338-348.
Snyder, N. F. R., S. R. Derrickson, S. R. Beissinger, J. W.
Wiley, T. B. Smith, W. D. Toone and B. Miller.1997a.Captive
breeding and conservation (reply to Hutchins, Wiese and Willis).Conservation Biology 11:3-5.
Snyder, N. F. R., S. R. Derrickson, S. R. Beissinger, J. W.
Wiley, T. B. Smith, W. D. Toone and B. Miller.1997b.Limitations
of captive breeding: reply to Gippoliti and Carpaneto.Conservation Biology
11:808-810.
Stoleson, S. H. and
S. R. Beissinger.1995.Hatching asynchrony and the onset of incubation in birds revisited: when
is the critical period?Current
Ornithology 12:191-270.
Stoleson, S. H., and
S. R. Beissinger.1997a.Hatching asynchrony, brood reduction, and food limitation in a
neotropical parrot.Ecological
Monographs 67:131-154.
Stoleson, S. H., and
S. R. Beissinger.1997b.Hatching asynchrony in parrots: boon or bane for conservation.Pages 157-180 in Behavioral
Approaches to Conservation in the Wild (J. R. Clemmons and R. Buchholtz, Eds.).Cambridge University Press, Cambridge, U.K.
Stoleson, S. H., and S. R. Beissinger.1999.Egg viability as a
constraint on hatching synchrony at high ambient temperatures.Journal of Animal Ecology 68:951-962.
Takekawa, J. E., and
S. R. Beissinger.1989.Dispersal, cyclic drought, and the conservation of the Snail Kite in
Florida: lessons in critical habitat.Conservation
Biology 3:302-311.
U. S. Fish and
Wildlife Service (USFWS).1995.Draft Recovery Plan Marbled Murrelet (Brachyramphus
marmoratus) (Washington, Oregon and California population).U.S. Fish and Wildlife Service, Portland, Oregon.171 pages.
Waltman, J. R. and S.
R. Beissinger.1992.The breeding biology of the Green-rumped Parrotlet.Wilson Bulletin 104:65-84.
(Forpus passerinus Chicks)
(Marbled Murrelet nest)
(Snail Kite - Rostrhamus sociabilis)
