[MDOsprey] See! A Loon!
Jlstasz@aol.com
Mon, 8 Nov 1999 19:11:10 EST
Hi Folks!
I have been following the Yellow-billed Loon reports with great interest, and
even took some time off work last Friday afternoon 11/5. I arrived at the
Sea Breeze about 3:30, glanced at the Kelp Gull, and then proceeded to look
for interesting birds. There was essentially no wind, no clouds, and the
river was flat. Visibility was excellent for several miles up and down river.
I scanned until about 5 PM with the tripod-mounted Swarovski at 20X, zooming
to 60x when anything needing a special look came into view. My tally of
loons was 1 Red-throated and 15 Common. Of interest among the latter were two
1st Winter immatures. Both of these had distinct scalloping on the back,
typical of the plumage. Less "typical", but not beyond the standard range of
variation, were the yellowish bills on both of these birds. On one the bill
was a very pale yellow with a culmen dusky along its entire length and the
mandible dark at the base. The other was a more striking bird, with a
brighter yellow [dull yellow, not bright like a male Mallard bill yellow or
the cover of a National Geographic magazine, but quite the eye-catcher] bill
that was dark only on the top basal third of the culmen and not at all dark
at the base of the mandible. I watched this bird at length. With the proper
angle and the right background, the dark base to the culmen blended into the
background and created the illusion that the culmen was straight.
Greg Miller joined me later and has previously commented on yellow-billed
Common Loons present on the river.
The differences between winter adult and winter immature loons is depicted in
the 3rd edition of the National Geographic Guide, but not the earlier
editions, nor in Peterson, nor in Robbins. The strong pale scalloping is
obvious at this time of year, but is lost through wear during the winter.
The Harrison SEABIRD guides also illustrate and discuss the plumage
differences attributed to age. In addition to the back feathers, Common Loon
immatures have paler bills than adults. In all winter plumages, the
coloration of the crown and nape of Common Loon typically appears darker than
the back, while in Yellow-billed Loon, the reverse is usually true.
I hope this helps. It pays for me to write it down since I frequently become
dyslexic when pointing out fieldmarks.
Good Birding!
Jim
Jim Stasz
North Beach MD
jlstasz@aol.com
ps: for the County Listers. The dividing line in this area is approximately
one mile into the river from Sandgates. It is about 1.75 miles to the Calvert
shore.