Status of the Broad-Winged and Red-Shouldered Hawks During Fall Migration in Southwestern Idaho, 1995-2006
Twelve years of counting raptors during fall migration near Boise, Idaho, yielded 214 Broad-winged and 9 Red-shouldered Hawks, revealing these species as much more frequent in Idaho than previously known. The Broad-winged Hawk is an uncommon, annual fall migrant in Idaho. The Red-shouldered Hawk is at least casual, possibly nearly annual, during fall migration. These data match increased sightings from other western states that have likely resulted from a combination of increased observer coverage and possible range expansions and/or numerical increases for both species in the West.
Carlisle, Jay D.; Kaltenecker, Gregory S.; and Brady, Ryan S.. (2007). "Status of the Broad-Winged and Red-Shouldered Hawks During Fall Migration in Southwestern Idaho, 1995-2006". Western Birds, 38(4), 251-260.