ML41691321
投稿者
日付
場所
- 年齢と性別
- 未成鳥 性別不明 - X
視聴覚メディア・ノート
This apparent hatch-year Cave Swallow was initially found the previous day by Jon Feenstra and here photographed in flight by Curtis A. Marantz on 1 December 2016 at Santa Fe Dam Recreation Area, Irwindale, Los Angeles County, California.
観察結果の詳細
My views of this bird as it flew over the lake and surrounding areas were more than sufficient to identify it unequivocally. I thought it was about two-thirds the size of nearby White-throated Swifts, or conversely, slightly smaller than the Tree Swallows. Its structure was typical of a swallow, in that relative to the swifts, this bird’s body was plumper and more compact, and its wings were broader at the base. I noted a bill that was small and inconspicuous, a head of unremarkable size, a neck that was short and stout, a body that was plump, wings that tapered from a broad base to a pointed tip, and a relatively short, square-tipped tail. Given the conditions under which I made my observations, it was almost impossible to determine the shape of this bird’s forehead and crown, its posture, or the relative length of the wings versus the body. What I can say was that the wings were relatively broad where they met the body, yet they tapered to pointed tips, and my impression was that the inner part of the wing was quite short, so the majority of the wing represented the primaries. It was difficult to determine the length of the tail relative to the body, but my impression was that the tip of the tail extended beyond the rear edge of the wings a distance that was not much longer than that between the leading and trailing edges of the wings. I never saw this bird’s legs or feet. This was a relatively boldly marked bird for a swallow, but the colors represented primarily earthen tones. I was able to notice on occasion that the forehead was a deep rufous to brick-red in coloration, and that it contrasted relatively sharply with a blackish cap that appeared to extend from a point a little before the eyes back to the nape and behind the eye down no further than the upper edge of the auriculars. As far as I could determine, the throat was a rich cinnamon-buff to peach color from the chin down to its demarcation with the breast, and the lower part of the face and auriculars were similarly colored right up to the eye and the lower edge of the dark cap. I noted no suggestion of darker coloration on the chin or throat, and my impression was that the cap was sharply demarcated behind the eye. I also thought the cinnamon-buff of the throat and auriculars continued broadly across the sides of the neck to pinch off the cap, but I was never quite sure if this color extended across the back of the neck. I am quite confident that the back and scapulars were blackish with what appeared to be at least some iridescence that tended toward green, if not bluish-green. I was unable to determine if there was any pale streaking on the back, however. The uppersides of the wings appeared to be quite dark, but I had a hard time determining their coloration. The rump had a well-defined patch of cinnamon that appeared to extend from the trailing edges of the wings back to either the uppertail coverts or the base of the tail. The rump patch was roughly square in shape, with the leading and trailing edges both extending straight across the body. The tail was certainly dark, but I found it almost impossible to determine its precise coloration. Returning to the underparts, the cinnamon-buff color of the throat extended down to its demarcation with the breast, where it merged relatively abruptly with the whitish color that extended down across the breast, belly, sides, and flanks. The undertail coverts were certainly pale, but at times I thought I noted at least some suggestion of buff. The underside of the tail was dark. I also noted that the undersides of the wings appeared to be uniformly dusky in appearance. I noted no obvious contrast between the color of the axillars, underwing coverts, and remiges. Given the distance at which I made my observations, it was almost impossible to discern the soft-part colors, but what I could see suggested that the bill and eyes were dark, or at least not obviously pale.
テクニカル・インフォメーション
- モデル
- Canon EOS 7D Mark II
- レンズ
- EF100-400mm f/4.5-5.6L IS II USM
- ISO
- 500
- 焦点距離
- 400 mm
- フラッシュ
- Flash did not fire, auto
- Fストップ
- f/6.3
- シャッタースピード
- 1/1600 sec
- 大きさ
- 613 pixels x 414 pixels
- オリジナルのファイルサイズ
- 123.04 KB