Re: [CALBIRDS] Re: Possible Manx Shearwater off of Mugu Rock
- Todd and CalBirders,
Thanks for your comments. As I said, I didn't have very long looks, and
only really noticed the underside of the bird the couple of times I saw it.
Unfortunately, I'm not familiar with Don Roberson's paper (I'd love a copy
if you find it or Don is reading this email), and my field guides don't
show a difference in the color of the upper parts. So, I appreciate any help.
The thing that did stand out for me when seeing the bird was the brilliance
of the white on the belly, vent, and wings, but that and the size are the
only field marks I can attest to. That's why I said "possible". I'd
appreciate if Todd or any others with more experience with separating Manx
and BV Shearwaters could go out and look.
At 04:50 AM 2002-03-04 +0000, toddamcgrath wrote:
>--- In CALBIRDS@y..., Steve Sosensky <Steve@S...> wrote:Good birding,
> > Hi All,
> > This morning I did a sea watch from Mugu Rock on Pacific Coast Hwy. in
> > Vertura Co. from 0730 to 0900. There was a flock of Black-vented
> > Shearwaters about 300 to 500 yards off shore. I viewed them with my scope
> > at 60x. In this flock was one Shearwater, about the same size, shape, and
> > color as the BVs, which had a white vent. Though I would have liked
> > longer, and closer looks, I think this was a Manx Shearwater.
>I wanted to point out a couple of things about Manx vs Black-vented
>Shearwater. First, vent color is not completely reliable as a mark. Don
>Roberson wrote an excellent article in Birding a few years back, and had a
>photo of a black-vented shearwater with a white undertail... Upon close
>inspection, the bird showed a creamy white undertail, with some darker
>smudges. ... It was never difficult to separate these birds from Manx, as
>they appear noticeably different due to the brownish color, creamy rather
>than white underparts, and the lack of strong demarcation between the
>black and White.
>In flight Manx is much darker than black-vented and clearly demarcated, a
>sharp black and white, as opposed to brown and smudgy. In flight, Manx
>often shows small white ovals at the sides of the
>rump, and appears a much cleaner white underneath.
>If the bird at Pt Mugu was close enough to observe vent color, but
>appeared in other respects similar to Black-vented, I would find it
>difficult to rule out one of the "white-vented" Black-vented Shearwaters,
>as the bird should have stood out in several other respects, as I noted above.
Steve <mailto:steve@...> for general use
<mailto:mobile@...> for rare birds and emergencies only
Steve Sosensky, photographer www.sosensky.com
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