ML583321551
Common/Arctic Tern Sterna hirundo/paradisaea
- 年齡
- 未確定
- 性別
- 未確定
觀察細節
First summer bird. Small head, no dark secondaries, mostly clean upper primaries with no strong carpal bar and no dark secondaries. Distant photos. Field ID / ID by people on the boat was Arctic Tern. Shopping for opinions, and no one wanted to touch this for a definitive ID, but most people lean towards Common Tern. Structure: Several people thought the bill looks long and is better for Common Tern. This seems to be an ambiguous feature on this bird, and open to interpretation. Plumage: The bird is in molt, having replaced all inner primaries while retaining P9 and P10. These outer primaries are clearly dark, whereas the fresher primaries are not noticeably dark. This is a difficult plumage to judge Common vs Arctic. Some inner secondaries may be retained older feathers and appear darker on the upperwing. On the underwing, the fact that the bird is in molt makes things difficult, but the trailing edge could be interpreted as fairly broad. All in all, perhaps plumage characteristics are not particularly useful for birds in this plumage, and this bird is not structurally obvious (but most people lean towards Common Tern), and a slash is probably the best conclusion.
技術資訊
- 型號
- NIKON D5600
- ISO
- 800
- 焦距
- 500 mm
- 閃光
- Flash did not fire
- 光圈值
- f/6.3
- 快門
- 1/2500 sec
- 次方
- 616 pixels x 413 pixels
- 原始檔案大小
- 66.4 KB