ML82775761

Age

Not specified

Sex

Not specified

Media notes

Short-tailed Shearwater photographed by Curtis A. Marantz on 13 January 2018 flying over offshore waters 7¾ kilometers southwest of Point Estero at 35° 24' 46" N, 121° 03' 40" W, San Luis Obispo County, California.

Observation details

Marantz initially saw this bird from the bow when it circled behind the boat and landed on the water in the wake 7¾ kilometers southwest of Point Estero at 35° 24' 46" N, 121° 03' 40" W. Given that the shearwater did not approach after we had moved a short distance, we turned around and motored back down our wake for better views. Even with a close approach by the boat, this bird remained on the water for an extended period before flying only a short distance and alighting again. Unfortunately, despite our studying this bird at close range and in good light when it was on the water, our views of the bird in flight were insufficient to gain more than a rough impression of the pattern on the underwings, and in fact, much of what we noted on the flying bird was taken from photos. The description below is by Marantz. This was a medium-sized shearwater that was at least somewhat larger than the Black-vented Shearwaters that we had been seeing in numbers, yet its overall structure and flight were similar (though the pace of the wingbeats was not noted). Seen clearly was that this was a plump bird with a short neck, a rounded head, a medium-length tail, and long, slim wings that tapered to broadly pointed tips. Most conspicuous was that this bird’s bill was short and relatively slim as it tapered from a base of medium-depth to a hooked tip along a culmen that dipped downward slightly in the center. Relative to a Sooty Shearwater seen later in the day, this bird’s bill was conspicuously short and slim, albeit probably not appreciably different in shape or proportions. Accentuating the small bill was a relatively steep forehead and a crown that may have had a more domed appearance than that of a Sooty Shearwater. The neck was of medium-length and at least relatively stout, and the plump body sat lower in the water than did those of the gulls. I did not think the wings appeared conspicuously long when folded and I noted no tapered wingtip. The tail was short to medium-length and photos showed it to be weakly wedge-shaped with the feet extending just beyond the tip. The legs and feet were either unseen or not noted in the field. This bird’s plumage was almost entirely a dusky-brown in color, yet we noted a pale gray to whitish throat was that was poorly defined. Evident only in flight was that the underwing coverts were extensively pale, yet seemingly light gray and not strikingly white. Moreover, the pale coloration on the underwing appears more extensive than that of a Sooty Shearwater on the one photo that seems to show this. The eyes were dark and the bill was dull blackish, or possibly a dark enough shade of gray as to appear blackish.

Technical information

Model

Canon EOS 7D Mark II

Lens

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

ISO

400

Focal length

400 mm

Flash

Flash did not fire, auto

f-stop

f/8.0

Shutter speed

1/1600 sec

Dimensions

1915 pixels x 1278 pixels

Original file size

3.8 MB