Dispersal and Survival of Red-Shouldered Hawks Banded in Suburban Southern Ohio, 1996–20181

Abstract

We used banding data to investigate dispersal and survival of Red-shouldered Hawks (Buteo lineatus) in two study areas in southern Ohio from 1996 to 2018. Of the 2448 nestlings we banded, 167 (6.8%) were encountered (dead or alive) some time after banding. Mean distance from the natal nest at the time of encounter was 31.6 6 6.2 km (median ¼ 10.0, range ¼ 0.1-568.6 km, n ¼ 163); natal dispersal distance averaged 16.0 6 1.9 km (median ¼ 9.0, range ¼ 1.4-117.1 km, n ¼ 110), and was significantly greater for females than for males. Most hawks dispersed ,30 km, but 11 hawks (6.7%) dispersed .100 km from their natal nest. Of these long-distance dispersers, nine (82%) were ,2 yr old, suggesting that some young birds wander widely prior to breeding. Dispersal distance differed by sex and age at encounter, with dispersal distance negatively correlated with age at encounter, and females dispersing farther (39.8 6 12.3 km) than males (22.8 6 9.86 km) and unknown-sex birds (33.9 6 10.6 km; all P , 0.05; means estimated from the logistical regression model). Dispersal direction for all birds followed a uniform distribution (P. 0.05); however, dispersal direction of long-distance dispersers was not uniform (P , 0.05) but bimodal, with hawks encountered either to the south or to the northeast of the study area. Mean age at recovery was 2.6 6 0.3 yr (median ¼ 1.5 yr, range ¼ 0.2-10.3 yr). As in other raptor species, apparent annual survival varied between age classes, with young birds (hatch-year and second-year) having lower apparent annual survival (0.49 6 0.03) than adult birds (0.76 6 0.03). Our study provides information on dispersal, survival, and causes of mortality of Red-shouldered Hawks, demographic data that are important for evaluating population trends and the sustainability of urban/suburban populations.

Phylogeography and species limits in the red‐shouldered hawk (Buteo lineatus): Characterization of the Northern Florida Suture Zone in birds

“…We found two studies of natal dispersal in B. lineatus that reported the standard error of mean dispersal distance and sample size for a total of three populations (Bloom, Scott, Papp, Thomas, & Kidd, 2011;Dykstra et al, 2004); these yielded estimates of root-meansquare natal dispersal distances of 22.9, 112.4, and 185.6 km; we used the median in further analyses. For S. varia, Livezey (2009) analyzed some band recovery data consistent with a root-mean-square total dispersal distance of 69 km.…”

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

“…In the course of an investigation of Red‐shouldered Hawk dispersal and survival (Dykstra et al . 2019), we searched for nests of this species in the urban and rural study areas of southern Ohio. Because Red‐shouldered Hawks in southern Ohio are resident year‐round (Dykstra et al .…”

“…Because Red‐shouldered Hawks in southern Ohio are resident year‐round (Dykstra et al . 2001, 2004) and begin courtship activities in mid‐February (with an average laying date of 22 March and an average hatching date of 23 April; Dykstra et al . 2004), we searched for nests between mid‐February and mid‐April, 1997–2016.…”

“…2001, 2004) and begin courtship activities in mid‐February (with an average laying date of 22 March and an average hatching date of 23 April; Dykstra et al . 2004), we searched for nests between mid‐February and mid‐April, 1997–2016. We used a variety of techniques to find nests, including searching where Hawks responded to call‐playbacks, searching historical nesting territories (J.…”

“…Thus, teasing apart the effects of both weather and habitat on reproductive rates of raptors requires a long‐term dataset, as exists for Red‐shouldered Hawks Buteo lineatus nesting in southern Ohio, USA (Dykstra et al . 2019).…”