Seasonal body weight variation in five species of woodpeckers

摘要: We investigated patterns of seasonal variation in body weight six populations five resident species temperate-zone woodpeckers: Acorn Woodpecker ( formicivorus), Red-bellied (M. carolinus), Red-cockaded (Picoi- des borealis), Downy (P. pubescens), and Great Spotted (Den- drocopos major). After controlling for time day overall size, annual was small generally not statistically significant. However, analysis re- vealed evidence significant ''winter fattening,'' comparable magnitude to other tem- perate-zone species, three the species. The degree winter fattening did correlate with either size acorn crop (for Woodpecker) or latitude, two variables potentially related predictability food resources. smaller exhibited significantly greater than larger as predicted by hypothesis that energy storage should be more important small-bodied Further- more, food-storing considerably less nonfood-storing supporting provides an eco- logical alternative fattening.