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Re: more info and pics of jaeger

Tim et al,

Well, I skipped the wig and nails, but loaded up on ice cream in preparation
for looking at more jaeger photos.  I shall foolishly tread where angels
fear to go.

I'm still stuck on Parasitic, although this bird still doesn't clearly add
up.  Here's my analysis.

Bill:  Still problematic.  Now the bill looks more correct for a
Long-tailed.  The nail looks to be about only 1/3, but your measurements
tell a different story--1/2, and that says Long-tailed.  The gonydeal angle
is better for Long-tailed, too.  This feature doesn't support the Parasitic
camp.

Primaries from outer wing:  A mixed field mark.  The feather shafts of P9
and P10 are obviously bright white (favoring Long-tailed), but the contrast
between them and P8's shaft is not as strong as I was expecting.  P8's
feather shaft is still more tan than white, but the difference doesn't knock
me over like the contrast in the Colorado jaeger's wing.  But turn the bird
over and the white on the base of the top primaries screams Parasitic.  More
on this one later.

On another note, I'm back to thinking this bird is a hatch-year juvenile
because the feathers are in such good shape and the primaries or secondaries
are so even-looking.  I think an older year juvenile would show flight
feathers of uneven lengths.

Body back side:  The warm tones on the scalloped feather edges don't look
whitish to me--are they buffy?  They're considerably darker than the really
white feather details.  Kaufman calls one color of the Parasitic's upperwing
covert edging 'golden buff'.  Long-tailed are described as whitish. The
white at the base of the primaries obviously extends onto the feather
itself, favoring Parasitic.  Isn't this the  white 'cresent' described in
several references?  Sibley says the white flash above is rare in other
jaegers and the feature showed up very clearly in every dorsal wing shot.
Tail coverts:  Parasitics are said to be irregular and of course, those
shown are washed with orange.  The references say Long-tailed are regular,
bold, and black-and white.  The problem for this bird?  The uppertail
coverts look like Parasitic and the undertail coverts look like Long-tailed.
But the color on both sets favors Parasitic.  I'm sticking with Parasitic on
tail coverts.

Body underside:  I can't tell the waviness of the barring from the photo.
Go grab that bird out of your freezer (right next to the ice cream?) and let
us know if the bars are wavy or straight. Bars on the Parasitic should be
wavy, except on the flanks; bars on the Long-tailed should be straight.
Also, your new set of photos is the first I've seen that shows the warm
orange tones on the body we saw Saturday night.  I was beginning to think I
had hallucinated the orange on both sets of tail coverts.  Steve and Jack
clearly described the color on the breast and lower body--but we couldn't
see it well in any photos.  All references describe the Parasitic as a more
colorful bird and the Long-tailed as cold brown with black-and-white tail
coverts.  The pale color on these coverts is orange.

Tail:  My favorite photo 'cause I'm a Parasitic weenie!  Shape and length of
the deck feathers is considered an excellent ID point.  Long-tailed should
be long and blunt; Parasitic's vary from slightly to noticeably longer, and
taper to a sharp point. In addition, Kaufman discusses the color.  A
Long-tailed often has whitish marks at the tip, whereas these marks are
lacking in the other two species. Our bird?  No white marks.

Undertail coverts:  Pattern is good for Long-tailed, bold and regular, but
aha!  They show that buffy wash.  Long-tailed coverts are termed
black-and-white.

Underwing:  I don't know.  I've given up and am getting tired of typing.
Would someone else address this one?

Measurements:

Body length--appropriate for the Long-tailed, but the wing span is not right
for any jaeger.  This bird is not fully grown.  Can we reliably use the
measurments as ID points?  I don't have any literature that discusses the
growth sequence (I apologize for that goofy statement).

My conclusion, once again:  the bird is a Parasitic with some atypical field
marks that I can't explain.

By the way...what's going on in that newspaper cartoon above the bird's
wrist in the underwing photo?!?  Is that really suitable content for a
birding listserv?

Kris
----- Original Message -----
From: "Tim Avery" <tanager@timaverybirding.com>
To: <birdtalk@utahbirds.org>
Sent: Tuesday, September 13, 2005 5:29 PM
Subject: more info and pics of jaeger


This afternoon at 2:30 I returned to the area where "our" Jaeger had
been, I unfortunately found the bird dead in the ruts in the mud about
1/4 mile past the second tape marking.  I immediately put the bird on
ice and returned to Salt Lake to photograph and document the bird. If
you would like to take a look please feel free, and let me know what you
think.  I will be donating the bird to the University of Utah, and will
deliver it tomorrow.

(Warning this is a dead bird, so if your not interested, disregard now!)

Bill:
http://www.timaverybirding.com/jaeger/bill_01.jpg

Primaries from the outer wing:
http://www.timaverybirding.com/jaeger/primaries_01.jpg

Body back side:
http://www.timaverybirding.com/jaeger/skin_01.jpg

Body under side:
http://www.timaverybirding.com/jaeger/skin_02.jpg

Tail:
http://www.timaverybirding.com/jaeger/tail_01.jpg

Undertail coverts:
http://www.timaverybirding.com/jaeger/under_tail_coverts_01.jpg

Under wing:
http://www.timaverybirding.com/jaeger/under_Wing_01.jpg


I also took several measurements:

Body Length from tip of bill to tip of tail: 15"
Body Width at chest: 5"
Wing Span from tip to tip: 36"
Tail Tip length from the end of the 2 central feathers to the tips of
the rest of the tail: 1"
Length of Wing from Elbow to P10 tip: 12.5"
Bill Length fro top of Upper mandible: 1.5"
Nail Length: .75"

Let me know what you think!

Tim
http://www.timaverybirding.com
http://www.birdingwyoming.org
Salt Lake City, Utah
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