ML112396961
- 年龄
- 未说明
- 性别
- 未说明
媒体文件注释
1st winter bird.
观察细节
About 60, most or all 1st cycle. These birds were similar to the S. hirundo associated with the flock but had much longer tail and frosted gray primaries with black outer webs only. They also had much less extensive to nearly absent dusky carpal patch, which I believe, is a character in 1st cycle birds only. In flight, at least one bird observed closely had a more rapid, shallow wing beat than hirundo. The pattern and extent of black in the nape and crown was variable enough that I could not discern any reliable difference between them and the hirundo present. They had long, thin bill, but then so did the 2¿3 hirundo with them, so I did not find this character to be diagnostic. These birds were videotaped.
技术信息
- 尺寸
- 434 pixels x 326 pixels
- 原始文件大小
- 25.52 KB