|ognizant Communication Corporation|
VOLUME 17, NUMBER 1
Bird Behavior, Vol. 17, pp. 1-8
1056-1383/05 $20.00 + .00
Copyright © 2005 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.
Mycoplasmal Conjunctivitis and the Behavior of Wild House Finches (Carpodacus mexicanus) at Bird Feeders
Erin R. Hotchkiss,1 Andrew K. Davis,3 John J. Cherry,2 and Sonia Altizer3
1Department of Environmental Studies
and 2Population Biology, Ecology, and Evolution Graduate Program,
Emory University, Atlanta, GA 30322, USA
3Institute of Ecology, University of Georgia, Athens, GA 30602, USA
Parasite infections can influence host foraging behavior, movement, or social interactions. House finches (Carpodacus mexicanus) in the US are susceptible to a recently emerged strain of the bacteria, Mycoplasma gallisepticum. Infected birds develop mild to severe conjunctivitis that could affect their foraging or social behavior. We videotaped house finches with and without conjunctivitis at a bird feeding station in Atlanta, GA to determine whether birds with conjunctivitis differed in feeding duration, efficiency, total food intake, or aggressive interactions. We observed 105 house finch feeding bouts (of which 41% were of birds with conjunctivitis). Infected birds spent more time at the feeding station and had smaller average and minimum flock sizes. House finches with conjunctivitis also showed lower feeding efficiency than noninfected birds in terms of seeds obtained per attempt and number of seeds eaten per unit time. However, because of their longer feeding bouts, birds with conjunctivitis consumed similar total numbers of seeds as birds without conjunctivitis. Finally, house finches with conjunctivitis were displaced from feeder perches less frequently than noninfected individuals and 75% of all observed displacement events consisted of an infected bird displacing a noninfected bird. Differences in flock sizes and feeding behavior of birds with and without mycoplasmal conjunctivitis could influence the fitness effects and transmission of this bacterium in wild house finch populations.
Key words: Infectious disease; Host behavior; Mycoplasma gallisepticum; Feeding behavior; Aggression
Feeding Behavior of Harlequin Ducks (Histrionicus histrionicus) Breeding in Newfoundland and Labrador: A Test of the Food Limitation Hypothesis
R. Ian Goudie and Ian L. Jones
Atlantic Cooperative Wildlife Ecology Research Network, Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland, Canada, A1B 3X9
We compared foraging behavior and productivity of harlequin ducks (Histrionicus histrionicus) in Newfoundland in 1997 and 1998, and central Labrador in 1997 to 2002, and tested predictions that productivity of this species is limited by available food. Females without broods were observed early in the nesting cycle (>70% of the local population), and were ascertained to be failed nesters. These adult females without broods were indicative of what previous researchers had defined as "nonbreeders." Productivity of harlequin ducks breeding in central Labrador ranged from 10.0% to 88.9% of females producing broods with 1.00 to 3.38 young per female present, annually. Females spent relatively low proportions of time feeding (mean ± SD: 0.385 ± 0.014 of ~17 h of daylight), and there was low variability across time and space. Therefore we inferred that foraging behavior was not tracking a variable food resource, and birds could have budgeted considerably more time to feeding if this had been necessary to meet their nutritional requirements. Physical evidence of nesting, including anatomical and radiotelemetry data, indicated that all adult female harlequin ducks in our study area attempted breeding each year. We found no support for the paradigm that females were constrained by lack of sufficient food on their breeding habitat and deferred breeding. We suggest that hypotheses such as food limiting breeding productivity can be tested using behavior that can be readily quantified, and with greater rigor than attempting to measure aquatic epibenthos in fast moving rivers.
Key words: Harlequin duck; Histrionicus histrionicus; Feeding behavior; Nonbreeding; Food limitation; Prey switching
Differences in Clutch Size and Reproductive Behavior in Show Versus Pet Budgerigars (Melopsittacus undulates)
Sabine G. Gebhardt-Henrich and Andreas Steiger
Division of Animal Housing and Welfare, Institute of Animal Genetics, Nutrition and Housing, Vetsuisse Faculty of the University of Bern, CH-3001 Bern, Switzerland
The aim of this study was to compare the reproductive behavior of large budgerigars bred by breeders attending exhibitions (show type) with smaller pet budgerigars (normal type). Compared with the normal type, show-type budgerigars were significantly heavier, had longer tarsi, longer wing feathers, longer feathers on the top of the head, and significantly larger spots on their throat feathers. Show-type females had a lower ratio of body mass to structural size (i.e., condition) than did normal-type females; such a low condition was associated with smaller clutches and egg cannibalism. Females paired with show-type males were less likely to lay eggs than those paired with normal-type males, although morphological traits within a pair were uncorrelated. Although the influence of male behavior on female reproductive behavior is unknown, all traits selected for in male show birds were negatively correlated with the frequency of flying from perch to perch and with reproductive parameters. Thus, there were some indications that budgerigars close to the breeders' ideal were less successful in reproducing than budgerigars resembling the wild type.
Key words: Behavior; Budgerigar; Exaggerated character; Reproduction; Captive breeding