SUPPLEMENTARY FOOD IMPROVES THE NUTRITIONAL CONDITION OF WINTERING WOODLAND BIRDS - EVIDENCE FROM PTILOCHRONOLOGY

Using the daily growth of induced features as an index, we found that supplementary food significantly improved the nutritional condition of wintering birds of several bark-foraging species, Downy Woodpecker Picoides pubescens, Carolina Chickadee Parus carolinensis, Tufted Titmouse P. bicolor, and White-breasted Nuthatch Sitta carolinensis. In many previous studies of the behavior and ecology of wintering birds, supplementary food on and off site both before and during study periods has remained an uncontrolled variable. We suggest that future work should incorporate knowledge about the accessability of artificial food supplies.