Dr. Tom A. Langen
Sociobiology and Cognition in the New World Jays
The New World Jays are a group of related birds that have provided a model system for comparative investigations of the evolution and ecology of kin-based sociality, and of cognition. I am have been involved in two projects focused on New World Jays.
One study is on the sociobiology and ecology of cooperative breeding in the White-throated Magpie-jay (Calocitta formosa), a highly-social Central American species. Magpie-jay social life focuses around territorial groups of related females, who cooperate in raising a brood of young that is primarily the genetic offspring of one female group member and one or two males. Males disperse from their natal group, and circulate as solitary 'floaters' until eventually joining with another female group. My research, and that of my collaborators, has been to understand the ecological causes and social consequences of the unusual mating and parental care system of these birds. We compare this species with other well-studied New World Jays to understand patterns in the evolution of social systems.
A second study has focused on choices made during foraging by Western Scrub-jays (Aphelocoma californica) and Blue-jays (Cyanocitta cristata). These jays store thousands of nuts during the fall, and carefully select nuts before transporting them to a caching site. I am conducting experiments on how these birds choose one item from a selection of similar items, and comparing these data to computer models of ‘optimal’ choice. This is a general type of cognitive problem that most animals face, for example when choosing a mate or home. I conduct field experiments with jays, collecting data on how individual birds sample and choose the heaviest nut from a selection of similar sized nuts. I have done analogous experiments with humans in the laboratory, examining how subjects sample and select the heaviest object (a weighted plastic egg) from a selection of similar objects. The goals of experiments with humans and jays are to understand some of the general principals and constraints on making accurate and economical choices in a frequently-encountered, cognitively difficult task.
Langen TA. 2004. Cognition: Food Storing. In Encyclopedia of Animal Behavior, Volume 1 (M. Bekoff, ed.), pp. 290-293. Greenwood Press, Westport CT.
Curry R.L, A.T. Peterson and T.A. Langen. 2002. Western Scrub-Jay (Aphelocoma californica). In The Birds of North America, No. 712 (A. Poole and F. Gill, Eds.). The Birds of North America, Inc., Philadelphia, PA.
Langen T.A. 2000. Prolonged offspring dependence and cooperative breeding in birds. Behavioral Ecology 11:367-377. reprint
Langen T.A. 1999. How western scrub-jays (Aphelocoma californica ) select a nut: effects of the number of options, variation in nut size, and social competition among foragers. Animal Cognition 2:223-233. reprint
Langen T.A. and S.L. Vehrencamp. 1999. How white-throated magpie-jay helpers contribute during breeding. Auk 116: 131-140. reprint
Langen T.A. and S.L. Vehrencamp. 1998. Ecological factors affecting group and territory size in the white-throated magpie-jay. Auk 115: 327-339. reprint
Langen T.A. and R.M. Gibson. 1998. Sampling and information Behaviour 55: 1245-1254.
Langen T.A. 1996. The mating system of the white-throated magpie-jay Calocitta formosa and Greenwood’s hypothesis for sex-biased dispersal. Ibis 138: 506-513. reprint
Langen T.A. 1996. Social learning of a novel foraging skill by white-throated magpie- jays (Calocitta formosa, Corvidae): a field experiment. Ethology 102: 157-166. reprint
Langen T.A. 1996. Skill acquisition and the timing of natal dispersal in the white-throated magpie-jay Calocitta formosa. Animal Behaviour 51: 575-588. reprint
Upton S.J., T.A. Langen and T.F. Wright. 1995. A new species of Isospora Schneider, 1881 (Apicomplexa: Eimeriidae) from the white-throated magpie-jay, Calocitta Formosa (Passeriformes: Corvidae) from Costa Rica. Systematic Parasitology 31: 195-199.
Press Releases & Clippings (linked)
A Scrub-jay is served a meal.
Image by Esther Oey
A Magpie-jay is a meal.
Image by Jesse Ellis.
last updated 17 August 2010