Smithsonian, National Museum of Natural History Research and Collections

Genetics Program

Northern Cardinal Nest containing three cardinal eggs, one Bronzed Cowbird egg, and two Brown-headed Cowbird eggs. Northern Cardinal Egg Northern Cardinal Egg Northern Cardinal Egg Northern Cardinal Egg Bronzed Cowbird egg Northern Cardinal Egg Brian D. Peer, Ph.D.

Visiting Researcher

My research focuses on the interactions between avian brood parasites and their hosts.  Brood parasites such as the Brown-headed Cowbird lay their eggs in the nests of other birds and rely on these “hosts” to raise their offspring.  Many hosts accept the eggs of the cowbird and end up raising fewer of their own young. This has serious conservation implications because it may be contributing to the decline of some songbird populations.  Much of my research has focused on the evolution of host defenses against brood parasitism, namely egg rejection behavior.  The research for my M.Sc. and Ph.D. degrees focused on the coevolutionary interactions between cowbirds and their grackle hosts.  Grackles are unusual because most species display egg rejection behavior despite not being parasitized, and no other selection pressures appear to account for this behavior.  Previous research suggested that this behavior is costly and should be lost in the absence of brood parasitism, which would allow parasites to re-exploit old hosts once they lost egg rejection.  These findings have significant implications for host-parasite coevolution in that they suggest once egg rejection evolves in some hosts it is maintained in the absence of parasitism and this may force cowbirds to become host-specialists similar to Common Cuckoos.

Place the cursor on the eggs in the nest above and look in the status bar below to find out the species of the eggs. Picture below is of a female Great-tailed Grackle.

Female Great-tailed Grackle

I am currently determining the extent to which other bird species retain host defenses when they are no longer parasitized.  This research is being conducted with Dr. Stephen Rothstein at the University of California Santa Barbara, and Dr. Robert Fleischer of the Genetics Program of the Smithsonian.  We are testing host populations in Alaska, California, and Bermuda for egg rejection that are not sympatric with brood parasites, but who are closely related to rejecter species that are sympatric with parasites.  We believe that these allopatric hosts may have inherited egg rejection from their close relatives prior to their split, and have maintained rejection in the absence of parasitism.  We are also assessing levels of mtDNA sequence divergence between these closely related populations.  These data will be used to estimate the amount of time since such populations have been freed from brood parasitism, and hence how long they have maintained rejection in the absence of brood parasitism.

EDUCATION                       

Postdoctoral Research Associate, Sept 2000-present, University of California, Santa Barbara & Genetics Program, Smithsonian Institution

Postdoctoral Research Associate, June 1999-Aug 2000, North Dakota State University & USDA, National Wildlife Research Center

Postdoctoral Research Associate, 1997-1998, University of Illinois

Ph.D. Zoology 1998, University of Manitoba

M.Sc. Zoology 1993, Eastern Illinois University

B.A. Biology 1989, Illinois Wesleyan University

SELECTED PUBLICATIONS

1. Peer, B. D., H. J. Homan, and G. M. Linz.Ý 2003.Ý Impact of blackbird damage to sunflower:Bioenergetic and economic models.Ý Ecological Applications 13:248-256.

2. Peer, B. D., K. S. Ellison, and S. G. Sealy.Ý 2002.Ý Intermediate frequencies of egg ejection by Northern Mockingbirds sympatric with two cowbird species.Ý Auk 119:855-858.

3. Sealy, S. G., D. G. McMaster, and B. D. Peer.Ý 2002.Ý Tactics of obligate brood parasites to secure suitable incubators.Ý Pp. 254-269 in Avian incubation: Behaviour, environment, and evolution (D.C. Deeming, ed.).Ý Oxford University Press, Oxford.

4. Linz, G. M., B. D. Peer, H. J. Homan, R. L. Wimberly, D. L. Bergman, and W. J. Bleier.Ý 2003.Ý Has an integrated pest management approach reduced blackbird damage to sunflower?Ý In Human conflicts with wildlife: Economic considerations (L. Clark, ed.).Ý National Wildlife Research Center, Ft. Collins, CO.

5. Johnson, K., and B. D. Peer.  2001.  Great-tailed Grackle (Quiscalus mexicanus).  In The birds of North America, No. 576 (A. Poole and F. Gill, eds.).  Academy of Natural Sciences, Philadelphia, and American Ornithologists' Union, Washington, D.C.

6. Peer, B. D., H. J. Homan, and S. G. Sealy.  2001.  Infrequent cowbird parasitism on Common Grackles revisited: New records from the northern Great Plains.  Wilson Bulletin 113: 90-93.

7. Peer, B. D., and S. G. Sealy.  2001.  Mechanism of egg recognition in the Great-tailed Grackle.  Bird Behavior 14.

8. Homan, H. J., G. M. Linz, and B. D. Peer.  2001.  Dogs increase recovery of passerine carcasses in dense vegetation.  Wildlife Society Bulletin 29:292-296.

9. Peer, B. D., and E. K. Bollinger.  2000.  Why do female Brown-headed Cowbirds remove host eggs?  A test of the incubation efficiency hypothesis.  Pp. 187-192 in Ecology and management of cowbirds and their hosts (J. N. M. Smith, T. Cook, S. I. Rothstein, S. K. Robinson, and S. G. Sealy, eds.).  University of Texas Press, Austin.

10. Peer, B. D., S. K. Robinson, and J. R. Herkert.  2000.  Egg rejection by cowbird hosts in grasslands.  Auk 117:892-901.

11. Peer, B. D., and S. G. Sealy.  2000.  Conspecific brood parasitism and egg rejection in Great-tailed Grackles.  Journal of Avian Biology 31:271-277.

12. Peer, B. D., and S. G. Sealy.  2000.  Responses of Scissor-tailed Flycatchers to experimental cowbird parasitism. Bird Behavior13:63-68.

13. Peer, B. D., and S. G. Sealy.  1999.  Parasitism and egg puncture behavior by Bronzed and Brown-headed cowbirds in sympatry. Studies in Avian Biology 18:235-240.

14. Peer, B. D., and S. G. Sealy.  1999.  Laying time of the Bronzed Cowbird.  Wilson Bulletin 111: 138-140.

15. Peer, B. D., and E. K. Bollinger.  1998.  Rejection of cowbird eggs by Mourning Doves: A manifestation of nest usurpation? Auk 115:1057-1062.

16. Peer, B. D., and E. K. Bollinger.  1997.  Common Grackle (Quiscalus quiscula).  In The birds of North America, No. 271 (A. Poole and F. Gill, eds.).  Academy of Natural Sciences, Philadelphia, and American Ornithologists' Union, Washington, D.C.

17. Peer, B. D., and E. K. Bollinger.  1997.  Explanations for the infrequent cowbird parasitism on Common Grackles.  Condor 99:151-161.

18. Bollinger, E. K., B. D. Peer, and R. W. Jansen.  1997.  Status of neotropical migrants in three forest fragments in Illinois.  Wilson Bulletin 109:521-526.

Smithsonian, National Museum of Natural History