|ognizant Communication Corporation|
VOLUME 14, NUMBER 2
Bird Behavior, Vol. 14, pp. 51-70
1056-1383/01 $20.00 + .00
Copyright © 2001 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.
Avian Cognitive Abilities
Irene M. Pepperberg
University of Arizona and MIT Media Lab
Being called a "bird brain" is generally taken as a derogatory comment on one's intellect, but research has shown that many avian species have abilities that rival those of mammals, nonhuman primates, and even humans. Avian cognition thus has been, and continues to be, a vibrant area of experimentation. This article presents some highlights of a selected group of studies on avian cognitive capacities and briefly discusses potential areas of future research.
Key words: Avian intelligence; Avian cognition; Avian communication; Evolution of avian intelligence
Mechanism of Egg Recognition in the Great-Tailed Grackle (Quiscalus mexicanus)
Brian D. Peer and Spencer G. Sealy
Department of Zoology, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
We tested whether great-tailed grackles (Quiscalus mexicanus) recognize their own eggs and reject any eggs that differ sufficiently from their own, or whether they simply reject discordant eggs from their clutches. Two grackle eggs were removed from three-egg clutches and replaced with artificial eggs in this way, making the grackle eggs the discordant eggs. All artificial eggs were ejected from the 10 nests that were manipulated, leaving behind the grackle eggs. These results indicate that great-tailed grackles are similar to other rejecters of foreign eggs, in that they apparently recognize their own eggs and reject eggs that differ sufficiently from their own.
Key words: Great-tailed grackle; Egg recognition; Egg rejection; Brood parasitism; Quiscalus mexicanus
Development of Common Tern (Sterna hirundo) Sibling Recognition in the Field
Brian G. Palestis1 and Joanna Burger2
1Department of Ecology, Evolution and Natural Resources,
Rutgers, the State University of New Jersey, New Brunswick, NJ 08901
2Division of Life Sciences, Rutgers, the State University of New Jersey, Piscataway, NJ 08854
Sibling recognition may be an important factor in the survival of young colonial birds, because it helps chicks to locate their nest sites within colonies. We examined the development of sibling recognition in common tern (Sterna hirundo) chicks using choice experiments conducted in the field. Chicks older than 3 days of age showed a significant preference for nestmates over foreign chicks. This preference was quite strong from 5 through at least 12 days of age, and 5- to 12-day-old chicks spent significantly more time near nestmates than did 3- to 4-day-old chicks. These effects of age were expected, because common tern chicks first become mobile enough for brood mixing to occur at approximately 4 days of age, and this mobility continues to increase as chicks age.
Key words: Kin recognition; Nestmate recognition; Behavioral development; Laridae
Effect of Human Presence on Foraging Behavior of Sandhill Cranes (Grus canadensis) in Nebraska
Joanna Burger1,2 and Michael Gochfeld2,3
1Division of Life Sciences, Rutgers University, Piscataway,
2Environmental and Occupational Health Sciences Institute, Piscataway, NJ 08854
3Environmental and Community Medicine, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854
The occurrence of more than 500,000 sandhill cranes (Grus canadensis) and millions of geese and other waterfowl each spring along Nebraska's Platte River is among the world's most impressive wildlife spectacles. This attracts large numbers of casual visitors, photographers, birdwatchers, and serious ecotourists, resulting in a potential for bird-human encounters and disturbance that could reduce feeding time and interfere with the accumulation of fat at this critical migratory stopover site. As part of a study of behavioral interactions of foraging cranes, we examined the responses to stopped cars by sandhill cranes feeding in flocks of various sizes at varying distances from the road. We drove transects parallel to and perpendicular to the Platte River and stopped our car as close as possible to each flock (at the point where the perpendicular from the nearest bird in the flock intersected the road). We observed the number of cranes feeding, watching (vigilant), sleeping, courting, and flying prior to stopping and during the first 30 s we were stopped. Cranes closer than 70 m from the road almost always interrupted feeding, became alert, and moved away, either walking or flying. Those more than 300 m from the road usually showed no response. Over the 6-week stopover period in the Platte River Valley, cranes may deplete food resources far from roads, and switch habitats closer to the road, subjecting them to more frequent disturbance.
Key words: Sandhill crane; Human disturbance; Foraging; Stopover
migration; Grus canadensis