Re: Pacific Loon at Hains Point
S. Harvey Mudd, MD (shm@codon.nih.gov)
Thu, 28 May 1998 15:02:10 -0400
On 5/27/98 Lou Nielsen wrote:
>Between 6:30 a.m. and 7:30 a.m. had two good long distance scope views and one
>close-up look at the Pacific Loon as it moved upriver from near the Officers'
>Club, crossing over to the Ohio Drive side and then returning to the other
>side.
>The light rather miserable with a light rain off and on, but there was no
>mistaking the soft gray, rather rounded head; gray nape, dark throat, straight
>black bill --- much daintier (stiletto vs. the dagger) than that of the Common
>Loon which was nearby for comparison (not in the same scope view). When the
>bird was preening, I noted a straight and fairly regular demarcation between
>the dark upperparts and the white underparts, seeing no bulge of white up into
>the black near the rump, nor was any white along the sides or rump visible
>when it was still on the water.
>
>Anyone out there able to help with the separation of Pacific and European race
>of Arctic Loon? It seems to me I should have tried to count the number of
>white stripes along the side of the neck or some such exercise.
>
>A great morning in D.C. with two Yellow-billed Cuckoos in the trees above to
>liven up the landbird scene.
>
>I fled as the buses began to arrive.
>
>Lou Nielsen
>Reisterstown, MD
>clodvigii@aol.com
______________________________________________________________________
Lou:
Based on my reading of recent articles on separation of Pacific and Artic
Loons, you did note the most important feature - the lack of the white flank
patch rising above the water-line toward thr rear of the bird, and said to
be present on both races of Arctic Loon.
The white neck stripes help also. In my opinion the white seemed to be
narrower than the black stripes between them, and at points narrowed so much
as to appear almost interrupted - again said to be characteristic of
Pacific. By my count there were four longish white stripes and three
additional shorter stripes anterior to them. Pacific are said to have 5-7
stripes; Arctic, 5-6 (or is it 4-6)?
The presence of a complete vent strap is said to be a trait of Pacific,
although Arctic may occasionally have small partial vent straps. When the
bird leaned to one side momentarily, I could see a good vent strap starting
on that side, but could not be sure it went completetly across the middle of
the bird. When the loon dove, for an instant I could see parts of a vent
stripe, but never could be certain it was complete. Did anyone else see
this feature more satisfactorily?
The rounded head, rather than somewhat flattened on top, is also more
consistent with Pacific than Arctic.
I have to add that all comments above about Artic Loon above are based on
reading, not on personal experience, because I have never seen an Arctic
Loon of either race.
Harvey Mudd
____________________________________
S. Harvey Mudd
NIMH/DIRP/LMB
Building 36, Room 1B-08
36 CONVENT DR MSC 4034
BETHESDA MD 20892-4034
tel: 301-496-0681; fax 301-402-0245
email: shm@codon.nih.gov