Date: Mon, 3 Jun 2002 10:35:24 -0400 Reply-To: Maryland Birds & Birding Sender: Maryland Birds & Birding From: Tyler Bell Subject: Re: Pacific Loon Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Jane and I also did a little research on Arctic vs. Pacific using = available material at home. Harrison's Seabirds is less than useful as it = classifies Pacific as a subspecies of Arctic. Maybe there's a newer = edition after the split of Pacific from Arctic. The fairly comprehensive = ID article in Birding vol. 29:3 1997 deals specifically with viridigularis,= the Siberian subspecies of Arctic Loon which would be more likely to show = up in Alaska or along the west coast. Lars Jonsson's "Birds of Europe" = deals with the nominate subpecies arctica which would be the more likely = bird to show up on the east coast. Jonsson shows Arctic Loon with a chin = strap which is definitely contradictory to the Birding article. Apparently = the viridigularis subspecies doesn't have a chinstrap. On Pacific Loon, = the auricular is dingy whereas on Arctic Loon, the auricular is clear = white to behind the eye. Also, the head shape on Arctic is more angular or = boxy whereas Pacific is smooth. The white on the flank of Arctic is = apparent in all plumages and Sibley states that this distinguishes it from = all other loons. When Jane and I reviewed our couple of minutes of video, = the white patch on the flank is visible sometimes but a various angles, it = disappears entirely. Also, the head shape is smooth which is clearly = apparent in Dave Czaplak's photos. So, as much as I'd love this to be an Arctic Loon, which would be a lifer, = I'd have to say it truly is a Pacific Loon. And, in the absence of Phil = Davis, I'd like to state that Pacific Loon is a review species anywhere in = Maryland so please document your sightings! Tyler Bell bell@acnatsci.org California, MD Wave that flag...wave it wide and high! Grateful Dead, U.S. Blues >>> shm@CODON.NIH.GOV 06/03/02 10:11AM >>> Bob, While Jim Stasz, Marion and I were admiring the Clopper Lake Pacific Loon last week we carefully noted the width, length and shape of the white = flank patches. I have to admit that my mind was fantasizing about the possibility of seeing Maryland's first Arctic Loon. However, upon returning to the car a few minutes later, a recheck of the articles by Andrew Birch and Cin-Ty Lee in Birding 29, 106-115, 1997 and Birding World 8, 458-466, 1995 - both devoted to field identification of Arctic and Pacific Loons, and how to distinguish them, and each with many photos - confirmed that the flank patches we had just seen on the loon in question were entirely compatible with Pacific, and not with Arctic. As summarized (p.111) in the Birding article, "Pacific Loons can show obvious white = above the waterline if they are swimming "high" or partly rolling over as if to preen, but they never show the shape and extent of white that Arctics display (Dunn and Rose: Birding 24, 106-107, 1992). The key is to note whether the white on the flanks extends up to the sides of the rump, indicatiing an Arctic Loon". That is, on the Arctic the posterior white patches "flare" to a greater extent above the waterline, rather than forming a straight boundary between the dark sides and the undersides. These features are seen in many of the photos in these articles. Plate 3 in the Birding World article shows an adult summer Pacific Loon with rather broad white flank patches, but they extend only about 60% of the distance from the mid-base of the neck towards the rear, and do not = "flare" at the back. With respect to the chin-strap (which we did not see well), the Birding article (p.112) says "On adults in basic plumage, a well-defined dusky chin-strap is diagnostic of Pacific Loon (Figure 10). Some Arctic Loons may show a slight dusky chin-strap (or an impression of one), but it is never an obvious, well-defined feature as it normally is in Pacific Loons. The absence of a chin-strap, however, does not necessarily denote an = Arctic Loon, because a small percentage of Pacific Loons, particularly juveniles, can have very faint, inconspicuous chin-straps (Schulenberg: Birding 21, 157-158, 1989)". Harvey Mudd =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D To leave the MDOsprey list, send e-mail to listserv@home.ease.lsoft.com with the following message in line 1: signoff mdosprey =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =========================================================================