ML535230371

Age

Not specified

Sex

Not specified

Observation details

2nd-cycle at the river mouth. Closely resembles SBGU except for less contrasting primaries that were nearly concolorous (but still fairly dark brown) with the inner primaries and rest of the wing. There is noticeable wear on all of the outer primary tips that suggests they were darker and more contrasting earlier in the season. While they appear more concolorous now, the outer webs and tips of the outer 6-7 primaries are still noticeably darker than the inner primaries. Alvaro suggested this is perhaps within the variation shown by SBGU, albeit a less frequent (and less familiar) appearance than 2nd-cycles with more contrasting wings, and that the darker than usual coverts on this bird reduces the expected contrast with the primaries. A SBGU x GWGU was considered based on the less contrasting wings, however there don't appear to be any other GWGU traits evident on this bird. Furthermore, other 2nd-cycle SBGU that have medium brown and weakly contrasting primaries (e.g., https://macaulaylibrary.org/asset/26858931) also do not show any definitive GWGU traits suggesting this is variation rather than hybridization, which is apparently rare between these two species. This identification is tentative and other opinions are welcome.

Technical information

Model

Canon EOS 5D Mark IV

Lens

EF100-400mm f/4.5-5.6L IS II USM

ISO

100

Focal length

400 mm

Flash

Flash did not fire

f-stop

f/5.6

Shutter speed

1/1250 sec

Dimensions

2394 pixels x 1596 pixels

Original file size

1.64 MB