Birds of the Great Plains: Family Accipitridae (Hawks, Eagles, and Harriers)

White-tailed Kite Swallow-tailed Kite Mississippi Kite Goshawk Sharp-shinned Hawk Cooper Hawk Red-tailed Hawk Red-shouldered Hawk Broad-winged Hawk Swainson Hawk Ferruginous Hawk Harris Hawk Golden Eagle Bald Eagle Marsh Haw

Birds of the Great Plains: Family Accipitridae (Hawks, Eagles, and Harriers)

White-tailed Kite Swallow-tailed Kite Mississippi Kite Goshawk Sharp-shinned Hawk Cooper Hawk Red-tailed Hawk Red-shouldered Hawk Broad-winged Hawk Swainson Hawk Ferruginous Hawk Harris Hawk Golden Eagle Bald Eagle Marsh Haw

Raptors on the East Coast: A Shift in the Timing of Autumn Migration

I tested whether or not raptors on the east coast are shifting the timing of their autumn migration. I analyzed 38 years of passage data at three count sites across New England: Hawk Mountain, Quaker Ridge, and Lighthouse Point. I studied four raptors with diverse natural history traits: Red-tailed Hawk (Buteo jamaicensis), Northern Harrier (Circus cyaneus), Sharp-shinned Hawk (Accipiter striatus), and Broad-winged Hawk (Buteo platypterus). I also investigated possible factors associated with any documented shift, including climate, distance of migration, diet, and population trend. Long-distance migrants should advance their migration and short-distance migrants should delay their migration, as reported for numerous taxa, including raptors, in Europe. Raptors that feed primarily on birds should advance their migration. Species advancing their migration should advance it further in warm years, while species delaying their migration should delay it further in warm years. Finally, I predicted that species in decline would show little or no shift in migration timing; species unable to adjust to climate change may be at a disadvantage. The Red-tailed Hawk and Northern Harrier delayed their autumn migrations past these three count sites, while the Sharp-shinned Hawk advanced and the Broad-winged Hawk showed no shift in its migration phenology. Some of these results match my predictions based on the raptors\u27 life history traits, but some do not, suggesting that North American raptors are responding to climate change differently from European raptors. The Broad-winged Hawk is the only raptor among the four species I studied that is not shifting and it is currently declining in population in the Northeast. This species may be more hard-wired to migrate at roughly the same time every year, and that inability to shift may be contributing to population decline

Nesting Of Raptors Uncommon In Iowa: Summary and New Records

The nesting status of the Turkey Vulture, Bald Eagle, Northern Harrier, Sharp-shinned Hawk, Cooper\u27s Hawk, Red-shouldered Hawk, Broad-winged Hawk, Swainson\u27s Hawk, Peregrine Falcon, Common Barn-Owl, Burrowing Owl, Long-eared Owl and Short-eared Owl is reviewed and previously unpublished records added. Also the potential for the Northern Saw-whet Owl and Osprey to nest in Iowa is discussed. Although several species are on the brink of extirpation as part of Iowa\u27s nesting avifauna, the Bald Eagle has returned as a regular nester. Over 100 previously unpublished nesting reports and some management recommendations are included

Raptor trapping at Wise Point Station: Year 2003 report

Large numbers of diurnal raptors from breeding populations across northern latitudes migrate south along the Atlantic flyway to reach winter destinations from southeastern North America to southern South America. Many of these birds become concentrated within geographic bottlenecks where they rest and forage. Each fall since 1978, staff, students, and associates of the Center for Conservation Biology at the College of William and Mary have trapped diurnal raptors near the tip of the Lower Delmarva Peninsula. The research objectives of this project continue to be 1) to monitor trends in the migration of several raptor species, 2) to learn more about the natural history of migratory raptors, and 3) to add to our understanding of migratory movements and pathways. During the fall of 2003, the Wise Point Station was operated on 52 days between 9 September and 23 November for a total of 359 hours. A combination of mist nets, bow nets, and dho-gaza nets were used in conjunction with lure birds to trap migrating raptors. A total of 516 raptors of seven species was banded resulting in an overall capture rate of 1.4 birds/operation hr. The project has recorded lower overall capture rates in only 2 of the previous 15 years. The 2003 season continued a downward trend in overall capture rate. Since 1989, capture rate has declined significantly at an average rate of approximately 6%/year. A decline in the capture rate of Sharp-shinned Hawks appears to be solely responsible for the decline in overall rate. The proportion of total captures accounted for by Sharp-shins has declined from more than 60% of total captures in the early 1990’s to less than 30% in recent years. The population-level implications of continued declines in capture rates for Sharp-shinned Hawks within the mid-Atlantic remain unclear. Six birds that were banded at Wise Point during the 2003 season have been recovered elsewhere. This includes 2 Sharp-shinned Hawks, 3 Cooper’s Hawks, and 1 Merlin. Recoveries ranged from Dover Delaware to Marathon Florida. The Merlin was banded on the 8th of October and recovered in Marathon, FL just 6 days later. A total of 19 birds were captured that had been banded previously elsewhere. These included a young, male Peregrine that was color banded in Canada

“What do birds in Nebraska eat?” Color Photo Section [March 2014, pp. 20–26]

Photographs of American Robins with Eastern red cedar berry and earthworm and Purple Martins with red admiral butterfly and snowberry clearwing moth (p. 20); Lazuli Bunting with millet, Grasshopper Sparrow with grasshopper, Cedar Waxwing with ornamental crab apples, and Herring Gull with unidentified fish (p. 21); Red-tailed Hawk with Eastern fox squirrel, Sharp-shinned Hawk with Eurasian Collared-Dove, Rough-legged Hawk with small mammal, and Cooper’s Hawk with House Finch (p. 22); Swainson’s Thrush with grain, Orchard Oriole with mulberry, Yellow-throated Vireo with unidentified fly, and Turkey Vulture with unidentified snake (p. 23); Pileated Woodpecker feeding juvenile, Downy Woodpecker feeding juvenile, Northern Cardinals sharing food, and Barn Swallows (p. 24); Western Tanager with orange, Northern Saw-whet Owl in nest box, Wood Thrush on nest, and Yellow-headed Blackbird males (p. 25); Cape May Warbler, Yellow Warbler with unidentified insect, Northern Parula, Magnolia Warbler, and Common Yellowthroat with unidentified insects (p. 26)

Nest-site selection by Sharp-shinned Hawks in Kentucky

Because Sharp-shinned Hawks (Accipiter striatus) are the most secretive of North America\u27s forest-breeding raptors, little is known about their breeding biology, including their preferred nesting habitat. In 2009 and 2010, I searched 248 forest stands in Kentucky and found 11 nests, all located in pines (Pinus spp.). Nests were at a mean height of 18.6 ± 1.4 m in trees with a mean height of 23.7 m and mean dbh of 38.2 cm. Nests were in mixed coniferous/deciduous forests, with a mean canopy cover of 77.6%. Comparison of the characteristics of nest sites and randomly selected unused sites revealed significant differences (P = 0.021). Discriminant analysis revealed that five variables (foliage cover, mean tree height, basal area, percent deciduous canopy cover, and distance from edge) permitted the best discrimination between used and random sites. Sharp-shinned Hawks nested in areas closer to edges and in areas with denser stands of taller conifers and denser understory. All nests were in stands of young (~25-50 years), even-aged conifers about 18 to 25 m in height, with the dense cover provided by the conifers likely providing protection from predators. Nest sites were also close to edges where stands of dense pines transitioned into areas with more, shorter deciduous trees and less foliage cover than nest sites. These adjacent areas may have provided better foraging habitat for nesting Sharp-shinned Hawks because small birds, their primary prey, are more abundant in mixed stands than in the dense stands of conifers where they nested

The Sharp-Shinned Hawk (Accipiter Striatus Vieillot) In Interior Alaska

Thesis (M.S.) University of Alaska Fairbanks, 198

Effects of Weather on Autumn Hawk Movements at Fort Morgan, Alabama

Migrating hawks were observed at Fort Morgan, Alabama during autumn 1995-1998. The three most abundant migrants were Sharp-shinned Hawk (Accipiter striatus), Broad-winged Hawk (Buteo platypterus) and American Kestrel (Falco sparverius). The three species accounted for 84% of all observations. Most individuals (\u3e 80%) were seen heading west. Compared with days with east and south winds, days with north winds were associated with significantly higher passage rates for all species, and passage rates of Broadwinged Hawks were significantly higher on days when both a cold front and north winds occurred than on days with north winds only. Hawks flew higher on east winds than on north and south winds, suggesting that hawks fly lower in winds that may blow them out over the Gulf of Mexico

Congeneric predators fill discrete niches created by the relative abundances of their prey species

To what degree is niche partitioning driven by underlying patterns in resources such as food, rather than by competition itself? Do discrete niches exist? We address these questions in the context of Cooper's and Sharp-shinned Hawks, two broadly sympatric, North American, bird-eating raptors in the genus Accipiter. We find that the resource base, as quantified by body masses of birds at bird feeders, is approximately lognormal (smallest birds are most abundant), with lesser modes (peaks) in abundance at larger body mass. The predators appear to exploit peaks in the resource base, with Sharp-shinned Hawks focusing on small prey items (median of 26.5 g), and Cooper's Hawks taking prey from the two most abundant peaks (both the small body mass peak and a lesser peak at medium body mass ~90g). We tested the ability of citizen scientists to distinguish these notoriously similar species, and we determined the influence of potential false positive detections on our conclusions. We find that citizen scientists struggle to distinguish these predators from one another, and 18% of Cooper's Hawks were identified as Sharp-shinned Hawks, while 27% of Sharp-shinned Hawks were identified as Cooper's Hawks. Yet, simulations show that this uncertainty did not jeopardize our qualitative conclusions.Funding provided by: National Science FoundationCrossref Funder Registry ID: http://dx.doi.org/10.13039/100000001Award Number: 1402506Data collected through the interactions add-on to Project FeederWatch. Eliot Miller tracks incoming observations, highlights unusual observations, and contacts contributors to confirm/refute such observations. This then is a cleaner and vetted version of the original FeederWatch interactions observations. User names, IDs, and email addresses are all stripped from the data