Mass, reproductive biology, and nonrandom pairing in Cooper's Hawks

Nonrandom pairings of Wisconsin Cooper's Hawks with respect to body mass have been observed. The behavior, which include findings of a disproportionate share in the subsequent breeding population from breeding adults of higher mass, indicate a direct correlation between nonrandom pairing and recruitment among falconiform species. The breeding behavior is explained through such factors as territory quality and the differential timing of migration patterns.