Anting Behavior in Birds: Ant Selection and Effect of ant Chemistry on Feather Ectoparasites
Active anting behavior occurs when songbirds apply ants to their feathers. During anting displays, a bird draws its wings forward in front of the head and swings its tail around to the far right or left. Both wing and tail feathers are then rubbed with ants held in the bird's beak. The potential associations among ants, feather ectoparasites and birds make anting behavior an important community-level interaction. Although this behavior is cosmopolitan in distribution and occurs in a wide variety of passerine birds, it remains poorly understood. This dissertation tested hypotheses about anting behavior through controlled experiments with captive songbirds in an aviary. Experimental results revealed that bird responses to ants included either consumption without anting behavior, anting displays without ant consumption, or consumption of manipulated ants following anting displays. Birds were highly selective of ant species for anting displays and chose ants from the subfamily Formicinae significantly more often than from the Myrmicinae. Camponotus, Lasius and Aphaenogaster ants were preferred and Pheidole and Crematogaster ants were rejected. Preferred ants were significantly more active than ignored ants and lacked aggressive stinging and biting behaviors. Temperature and humidity did not affect anting displays, but significantly less anting episodes occurred on cloudy days. Feather molt condition was unrelated to anting behavior. Polar and non-polar extracts of preferred and ignored ants were tested for microbial inhibition of potential feather parasites. No extracts inhibited growth of the bacteria Bacillus subtilis, B. licheniformis strains 138B and 1432B or the fungi Chaetomium globosum, Penicillium chrysogenum, and Trichoderma viride or fungal spore germination. Formic acid inhibited growth of all microbial species and spore germination of C. globosum. Dust bathing site location in Wild Turkeys was not related to the presence of preferred ant species, indicating no association between anting behavior and dust bathing activity. These experiments represented the first controlled quantitative study to identify biotic and abiotic factors involved in this widespread and complex behavioral pattern.
Anting, Aphaenogaster, Bacillus licheniformis; Birds, Camponotus, Feather, Ecology and Evolutionary Biology, Ornithology, Zoology
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