ML613668994
作者
日期
地点
- 年龄
- 未说明
- 性别
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观察细节
Swift seen flying low over SE Cell, very familiar with CHSW and was quickly impressed by the small size of this bird with a shorter body, more stubbed tail, wings also appeared shorter and narrower, wing beats seemed really sharp but more shallow than CHSW. Pictures confirmed the paler throat extending to the lower chest and a pale contrasted gray rump to the wings and back. No vocalizations. Though both species of swift are rare in the winter regionally I would expect Vaux’s to be more expected. Notes later 1/17/24 Small swift with very pale throat and underbelly. Some images show just a pale throat but one image has good lighting on the entire underbelly showing pale feathering throughout. The rump is interesting in that it is slightly paler but not uniformly gray. The palest part of the rump is at the upper edge where the rump meets the back a small bright pale patch is evident in several shots. Interestingly several of the Louisiana VASW in years past have shown this same feature which is not typically apparent in most of our breeders. Maybe this is a SY and the pale rump is still developing or I wonder if a separate subspecies is at play (highly unlikely as the Central American populations are primarily sedentary). The bill size can also be a helpful mark to look for in separating CHSW vs. VASW. CHSW has a slightly larger bill with a bit more of a hook to it while VASW has such a tiny bill it almost barely shows up. There is certainly size variation in the bill of both species perhaps due to sex but this ones bill is tiny which sides more along with VASW. Finally the neck/head structure is important to note. CHSW almost like COHA have a more protrusive head having a slightly more necky look which also makes the general structure much more angular. VASW has a very short neck look with a very rounded head which is a lot like a swallow. This individual has a much smaller neck and more rounded head in profile also pointing to VASW. Finally the proportion of the bird is worth noting with a fatter body relative to the shorter wings which is more proportional to a swallow than to the long-bodied, long-winged CHSW. Flight style is something I pay close attention to as a professional hawkwatcher and seabirder and this individual as I noted in my earlier brief description was much more rapid wing beats and seemingly not nearly as deep overall compared to a CHSW. Initially upon seeing the bird I was surprised with its flight and general structure to find it to be a swift as it was much different than the CHSW I am used to seeing.
技术信息
- 型号
- NIKON D3400
- ISO
- 200
- 焦距
- 300 mm
- 闪光
- Flash did not fire
- 光圈
- f/7.1
- 快门速度
- 1/1600 sec
- 尺寸
- 1044 pixels x 926 pixels
- 原始文件大小
- 405.66 KB