Subject: Morning at Green Lake
Date: Apr 19 14:10:48 1996
From: Patricia Tucker Stroh - tri at seattleu.edu


Hi Tweets,
During my brief but full walk along the west side of the lake this
morning, I discovered that the city has finally carried out its plans to
cut down more of the large cottonwoods along the north edge of the lake.
A sad loss for me, though I understand their rationale about the old-age
trees dropping major limbs onto passersby during windstorms. Also, I
imagine, a sad loss for the House Sparrows who seemed to be building
nests in hollows in the sides of the trees. But I took the opportunity to
explore these hollows in the downed trunks, to see what I could learn
about sparrow nests (or at least popular holes). I found three hollows about
the size of the ones the sparrows were using (?) and poked around in
them; in two was very fine, medium-brown mud, soft and moist but not wet.
I couldn't discern any structure with my fingers, but perhaps it'd be
apparent if I'd used only a flashlight (crouched on my side between
trunks in the midst of dozens of walkers--would've been quite a
sight...). A third hollow yielded darker, dryer, coarser mud mixed with
mm to cm-long pieces of vegetation and some light-brown specks (seeds?).
This mud came out in balls: the largest was about a cm in diameter,
others a few mm. Nothing that looked or felt to me like a nest in any of
the three holes.
Further southwest along the path was the first Yellow-Rumped
Warbler of the day. I'm new at these, so I had to look up in my Natl G
book to confirm that it was a Myrtle's. It was calling softly, barely
opening its beak. Once I recognized the call, I heard another off to the
southwest. Close to the Bathhouse was an Audubon's, calling but more
loudly than the Myrtle's. Then I began hearing many such calls, mostly
emanating from the cherry grove west of the Bathhouse. (I love that feeling of
the world opening up around you when you first recognize something that's
probably been going on all along!) The three additional Y-R warblers that
I actually saw this morning were all Audubon's.
Made it down to the island before the rain really got going. Barn
swallows have joined the Tree and Rough-Winged. No sign of activity at
the possible Tree Swallow nesting site that Martin Muller and I saw the
other day, though I didn't watch for long enough. But several Tree
Swallows were hanging out noisily at a dead trunk between the Bathhouse
and the island.
A Flicker question left over from last month in my notes: I
watched one pecking at a loose chunk of birch bark on a tree by the lake.
The chunk was hinged on the right side to the rest of the tree. The
flicker seemed to know just where to hammer to break off the chunk at the
joint: only about 3 out of 15-20 pecks were off the hinge. I was pretty
impressed that the bird would recognize the weak part of the structure
that would maximize its pecking efficiency (fewest pecks to detach the
chunk, assuming that that was indeed its goal). How do they perform this
recognition, I wonder? Sound of the peck? Ease of penetration: not too
easy or too difficult? Sight? Or just luck, and I happened to catch a
statistical anomaly?

Happy birding,
Trileigh Stroh