American Kestrel (Falco sparverius) Science Article 20
Reports of birds exhibiting unusual incubation behaviors are perhaps not surprising, giventhe wide variety of physical properties that can elicit incubation responses in birds (seeBaerends and Drent 1982). Birds that normally are solitary nesters occasionally have beendocumented sharing the same nest site (Terres 1982, Fournier and Hines 1996).
RUSSELL D. DAWSON AND GARY R. BORTOLOTTI, Wilson Bull., 109(4), 1997, pp. 732-734