Paper: Raptors breeding on weaver nests in trees and on man-made structures2019-03-29 (835)
Raptors are known to breed on top of weavers nests but are they willing to follow the weavers onto man-made structures?
Paper: Oschadleus HD. 2019. Raptors breeding on weaver nests in trees and on man-made structures. Ostrich 90(1):85-88.
Abstract. Several raptor species nest on top of large weaver nests. These weaver nests are usually sited in trees, but 11.7% of Red-billed Buffalo-Weaver Bubalornis niger and 25.7% of Sociable Weaver Philetairus socius nests occur on man-made structures. In an extensive literature search, a total of 16 raptor species were recorded as nesting on top of weaver nests. At least 10 raptor species used weaver nests built in trees. Seven raptor species used weaver nests on man-made sites and four raptor species only used weaver nests built on man-made sites. No owls have been recorded as using weaver nests on man-made sites. There are historical records of raptors nesting on top of weaver nests in trees, while nesting on top of weaver nests sited on man-made structures appears to be a more recent adaptation. Costs and benefits of nesting on man-made sites are briefly listed. Nesting on man-made sites may increase (by both weavers and raptors) and raptor researchers are encouraged to document cases of raptors nesting on weaver nests where these are placed in trees or artificial sites, so that there is a record of changes in frequency of nest site usage by raptors.
Raptor species listed in the paper:
Secretarybird Sagittarius serpentarius