ML605819441

Age

Not specified

Sex

Not specified

Observation details

[TAB notes] As we were watching several Least-Storm Petrels flying around about 20-30 meters off shore, I noticed a white-rumped bird among the group, joined several minutes after by a second. These two birds were very accommodating, making several close passes by the shore where we were standing, allowing excellent views and photo opportunities, as well as direct comparisons with Least Storm-Petrels. There birds had obvious bold white rumps (upper tail coverts) wrapping around the sides of the rump and extending on the lateral edges of the under tail coverts, contrasting with the blackish color of the remainder of the plumage. The anterior edge of the white rump was straight while the posterior edge tapered to a point, forming a more or less triangular shape to the white rump patch that extended most of the way to the tail. They were the same size or only very slightly larger than the Least Storm-Petrels, and flew with the same direct flight and deep wing strokes as that species. The outer-most tail feathers were slightly longer than the inner tail feathers, so the tail appeared either squared-off or widely notched, but was not forked. Based on other reports of storm-petrels from California, Arizona, and Nevada, this appears to be the dominant (perhaps only) species of white-rumped strom-petrel associated with the avian fallout from Hurricane/Tropical Storm Hilary. We scanned the flock multiple times very carefully attempting to obtain accurate counts and came up with a total of 15 storm-petrels including three Wedge-rumpeds and 12 Leasts.

Technical information

Model

Canon EOS R7

Lens

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

ISO

400

Focal length

349 mm

Flash

Flash did not fire

f-stop

f/6.3

Shutter speed

1/2500 sec

Dimensions

1253 pixels x 969 pixels

Original file size

284.76 KB