UID
Digital Object Type Rare birds documentation form
Content DM Link https://n2t.net/ark:/87292/w9bn9x556
Type Text
Description Records Committee review of a Ferruginous Hawk at Hitchcock Nature Area in Pottawattamie County, IA on December 5, 1999. Includes a record review document with votes and a documentation form submitted to the committee.
Related Genres Administrative records Field notes
Sort Date 1999-12-05 - 2000-11-28
People / Organizations
Time 9:00 AM
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Collection Iowa Ornithologists' Union | MS 166
Box 9
Folder 1
Contributing Institution Iowa State University Library Special Collections and University Archives
Creator / Author Orsag, Mark
Contributors Iowa Ornithologists' Union Records Committee
Topics Bird watching Ornithology Ornithology--Societies, etc
Birds Ferruginous Hawk
Locations Hitchcock Nature Area
Map
Verbatim Locality Hitchcock Nature Area (Lodge Hawkwatch Point)
Location Remarks The documentation forms do not include georeferences
Habitat Loess Hills / Missouri River Valley. The bird was coming from out of the valley. It crossed the wooded ridges of HNA and headed southeast.
Extent 8 pages
Language(s) eng
Bibliographic Citation
Information Withheld
Individual Count 1
Occurrence Remarks The documentation form by Mark Orsag is the earliest and the one that forms the basis of this record. | Elimination of similar species: I considered 5 other species of raptor in total. I eliminated two possibilities (Rough-legged Hawk and Northern Harrier) within seconds of seeing the bird in question. I eliminated two others (Bald Eagle [imm.], and Red-tailed Hawk more or less during the minute or so that I had the bird in view. **** ** I reviewed, in my head, the fine points of the Krider's Red-tailed Hawk for a few seconds after the bird had disappeared from view. The fifth species came to mind just before I started writing this report (the next day). I retroactively eliminated it. In reconstructing my reasoning, I believe: Rough-leg was eliminated due to the unmarked white throat, breast, underwings, and underside. Northern Harrier was eliminated due [sic] the large size and robust shape of the bird, the flight pattern (especially wingbeat), the unstreaked white throat, etc. Immature Swainson's Hawk later eliminated by dark head, white wing patches on primaries, lack of dark flight feathers on underwing, unlikelihood of December sighting. Bald Eagle immature- (whitebelly I-II) was eliminated by the downpushing wingbeat, the colors of the bird's dorsal surface, the lack of a contrast on the dorsal surface between the brown-gray forward part of the wing and the darker flight feathers (a little known good fieldmark for Immature BE), and the confining of the white coloration to the primaries, etc. Red-tailed Hawk-This species, in light of its similar (but smaller) size and variable plumages, posed the greatest problems. The dark upper surface, dark head, pointed wings, and pattern of flight (dihedral in glide posture), as well as the distinct and identical nature of the white markings on the upperwings and the lack of patagial marks, "commas", or other dark markings on the underside, were considered in total and used to rule out the immature light-morph Red-tail and, on reflection, a partial albino Red-tail. Krider's Red-tailed Hawk was the toughest to rule out. Here are my reasons: 1. Krider's heads appear white/light in contrast to the darker (gray or brown) color of the back. This bird's head was not lighter in color (on top) than the back. Back coloring was too dark (brown-reddish) for Krider's-no white mottling seen. Wings were pointed not rounded. No 'headlight' fieldmark [sic] was seen and the 'points of light' fieldmark [sic] was. Dihedral in glide unusual but not impossible for a Red-tail, but the wingbeat (fluid and downpushing rather than centered on the downstroke at the wrist) did not look like a Red-tailed's. | The original documentation form event lasted from 09:00:00/09:01:00.
Occurrence Status present
Field Number 1999-32
Event Remarks Viewing Conditions: Light conditions were good-optics were 30x90 tripod mounted binoculars. * [...] * 30x90 tripod-mounted binoculars produced for the Russian military by the Zagorskii Optical and Mechanical Factory. Hand-ground optics/high quality.
Supporting Documentation
Date Digital 17 May 2017
File Type image/jpeg
Hardware / Software Epson - sheet feed