From surveys in many countries, we report raptors using unusual nesting materials (e.g., paper money, rags, metal, antlers, and large bones) and unusual nesting situations. For example, we documented nests of Steppe Eagles [Aquila nipalensis] and Upland Buzzards [Buteo hemilasius] on the ground beside well-traveled roads, Saker Falcon [Falco cherrug] eyries in attics and a cistern, and Osprey [Pandion haliaetus] nests on the masts of boats and on a suspended automobile. Other records include a Golden Eagle [A. chrysaetos] nest 7.0 m in height, believed to be the tallest nest ever described, and, for the same species, we report nesting in rudimentary nests. Some nest sites are within a few meters of known predators or competitors. These unusual observations may be important in revealing the plasticity of a species' behavioral repertoire.

Three banding stations were located in south-central Indiana (2002–07) to study migration patterns of Northern Saw-whet Owls (Aegolius acadicus). Saw-whet owl captures ranged from 59 in 2002 (1 station) to 447 in 2007 (3 stations), with 2007 an irruption year in at least one location. The proportion of hatch-year owls was 54.8% on average, but lower in 2004 (30.9%). Hatch-year owls consistently arrived 4–5 d earlier than older saw-whet owls in south-central Indiana. We used morphometric sexing techniques to classify 80% of the saw-whet owls we captured as females, and 7% as males. Encounters of birds banded at other stations indicated that most owls captured in south-central Indiana in fall had migrated around the west side of the Great Lakes. The irruption of 2007 was likely due to a large influx of saw-whet owls moving through the Ohio River Valley from eastern regions. Greatest numbers of saw-whet owl captures were associated with clear nights and relatively calm west-to-northwest winds after the passage of a cold front. For owls captured at our station and another, we calculated the average migration rate of 28.8 ± 15.8 km/d (N  =  9).

Annual bird mortality in the United States from anthropogenic sources is estimated at one billion. Urban raptors are affected by many of these factors; however, little is known about the relative frequency and magnitude of sources within and among species. I reviewed 86 published sources on mortality and urban use for the raptors of the United States and Canada. Within the Falconiformes (28 urban species), vehicle collisions and electrocutions were reported for most species (73% and 48%, respectively), and vehicular and window strikes were the leading sources of mortality for 39% and 12% of species, respectively. For the Strigiformes (14 urban species), vehicular (63%) and window (47%) collisions affected most species, and the primary sources of mortality were from vehicles (32%) and electrocution (5%). Window-strike mortality was reported for 45% of urban raptors and represented the leading source of mortality for Sharp-shinned Hawks (Accipiter striatus), Cooper's Hawks (A. cooperii), Merlins (Falco columbarius), and Peregrine Falcons (F. peregrinus). Mortality by electrocutions was also observed for 45% of the species. Collisions with vehicles affected a large proportion of urban and nonurban raptors, both for species that use roadways for various activities (e.g., foraging) and for those that do not use roadways. Overall, the literature suggested that collisions and electrocutions are important sources of mortality for most raptors. Future work should directly assess the consequences of these sources on life history and demography of raptor populations.

Although several phylogenetic studies of Gyps species have been conducted, few studies have addressed the genetic diversity of these species on a finer scale such as microsatellite analyses. We collected samples of migratory adults and nestlings from four species of vultures in six different localities. We analyzed the samples using microsatellites in order to determine the genetic distance as well as the amount of variation within and among Gyps species populations. Low genetic diversity in Long-billed Vultures (G. indicus) was probably indicative of a single population with no immigration and low gene flow. As this species is critically endangered, future conservation programs should consider genetically suitable stock for a breeding and reintroduction program. High genetic diversity in African White-backed Vultures (G. africanus) was likely indicative of a number of populations, with immigration and gene flow. We confirmed previous findings of low genetic differentiation among Griffon Vulture (G. fulvus) populations, which indicated high mobility and gene flow among these populations.