COLLABORATIVE RESEARCH: Complexity and Information in Avian Signals

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Drs. Nowicki and Searcy propose to test whether early nutrition affects the development of song in birds. Song development and production are controlled insongbirds by a series of well defined brain areas, which develop to a large extent during the first two months after hatching. In many species, the detailsof song are learned during this same two month interval. Nowicki and Searcy hypothesize that nutrition during this period affects the development of the song control regions in the brain and consequently affects song learning. As a test, they will manipulate level of nutrition in hand-reared sparrows during thefirst three weeks post-hatching. The sparrows will be tutored with tape-recorded songs, and the songs produced by these birds as adults will be recorded. The stressed and unstressed groups will be compared for the quality of learning, in terms of how faithfully they have copied the notes of the tutor songs, and for the quantity of learning, in terms of how many songs are learned per individual. The brains of the two groups will also be compared, for the size of the song control regions and the density of neurons in those regions. Finally, the songs of stressed and unstressed birds will be compared in terms ofhow well they function on ecologically relevant tasks.The idea that stress early in life affects brain development and hence learning ability is applicable to a wide variety of organisms, from birds to humans. Song in songbirds provides an excellent model system for studying such effects, in that the neural control, development, and ecological function of the behaviorare all relatively well known. The study will use this system to enhance our understanding of the effects of nutrition on the development of complex behaviors.