Habitat and weather conditions influence reproductive rates of suburban and rural Red‐shouldered Hawks Buteo lineatus

Abstract

Both habitat and weather can strongly influence reproductive rates of birds. We measured reproductive rates of suburban and rural Red‐shouldered Hawks Buteo lineatus in southern Ohio, USA, from 1997 to 2016, and then tested how weather conditions and habitat in the areas surrounding the nest‐sites were related to two measures of reproductive rate. Reproductive rates of Red‐shouldered Hawks did not differ between the suburban and rural study areas, and were relatively stable from year to year. Suburban Red‐shouldered Hawks produced 2736 young in 1773 nesting attempts (i.e. nest with eggs) at 302 territories (1.54 young per nesting attempt), and rural‐nesting Hawks produced 996 young in 640 nesting attempts at 108 territories (1.56 young per nesting attempt). Annual nesting success averaged 58.9 ± 1.1% for suburban birds and 58.9 ± 2.1% for rural birds. Several factors influenced Red‐shouldered Hawk reproductive rates, measured as either the number of young per nesting attempt or the percentage of nesting attempts that were successful. Higher air temperatures during May (the nestling period) and increasing amounts of coniferous forest were associated with higher reproductive rates, whereas increasing April air temperatures and increasing amount of grassland cover had the opposite effect. Land cover variables associated with suburban landscapes, such as the amount of residential development, did not influence the number of young per nesting attempt or nesting success, suggesting that Red‐shouldered Hawks are welladapted to human‐dominated landscapes in southern Ohio. Our study also illustrates the value of long‐term datasets for improving our understanding of factors that affect raptors’ demographic parameters.