Date: 11/21/20 5:20 pm
From: Robert O'Brien <baro...>
Subject: [obol] Petrel vs. Shearwater
After some study I'll have to agree with Jeff's immediate identification as
Great-winged Petrel.
Additional photos would be very, very helpful, even if blurry' and of
course, as Jeff mentions, flight style.
The main distinction is a very different shape/jizz in the photos attached.
Great-winged has a much stubbier bill as this bird shows and a different
overall shape, even though about the same size.
See attached comparison with Short-tailed and Sooty Shearwaters, the only
real competitors.
I've posted this photo previously a few years ago as a distinction between
the two shearwaters. My main computer
with the original image is currently dead, awaiting resurrection. This one
has a bunch of lines indicating comparative sizes
of the two. The sizes are quite different. Just ignore the lines in this
situation which apply only to the shearwaers..
Note the quite different bills in all 3. Sooty and Short-tailed narrow but
different in length.
Note the short stubby bill on the Petrel. The overall size/shape of the
neck/head is bulky in the Petrel and slender in both shearwaters.
Note the rather sharp wing-tips of the shearwaters and the blunter tips of
the Petrol.
Both of these marks are discussed in field guides, particularly in er
Harrison's *Seabirds*.
The stubby bill shows well in Ed McVicar's photos:
https://www.flickr.com/photos/10665268@N04/albums/72157609277544338/with/3038351657/
I fully realize that the relative shapes of flying seabirds can vary with
wind, current flight, etc. Nevertheless, IMHO I'm pretty confident of
Jeff's original ID.

 
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