Early phases of the breeding cycle of Tree Swallows (Iridoprocne bicolor).

Abstract

While much has been written about the Tree Swallows, I find a relative scarcity concerning the early phases of the breeding cycle. Most of the studies have been concerned largely with Tree Swallows nesting in nest boxes. This paper is an attempt to bring together some of the information from the literature and to include material from my own observations. Most of my observations took place during the spring of 1954. Part of them were in the Muskegon, Michigan region, the rest at UMBS in Cheboygan County, Michigan. In Muskegon the Tree Swallows were nesting in natural cavities and other available cavities. At the Biological Station the Tree Swallows were nesting in nest boxes.