The Laying of Replacement Clutches by Falconiforms and Strigiforms in North America
Abstract
This paper discusses the laying of replacement clutches by North American raptors by reviewing existing literature and presenting data gathered from oological collections and from the double-clutching of wild and captive birds. We found that most species recycle; however, the frequency of recycling declined with an increasing stage of incubation. Clutch size did not decrease significantly between layings for most species. Although a single replacement clutch was usually laid, multiple replacements are known. After loss of the first clutch, raptors usually renested in the same site. If a new location was used, it was usually in close proximity to the original site. Although data from areas north of southern Canada were scarce, it appeared that recycling was rare in arctic regions. We concluded that double-clutching can be used in most management plans for North American raptors.
