Nathaniel Peters mentions seeing 150 crows on the ice of Greenlake. I have
seen crows following others to investigate potential food resources. For
example, one day a shopper left a used white paper bag on a shopping cart in
the parking area near my classroom. Within about 5 minutes there were
dozens, maybe a hundred crows, all which apparently followed somebody else
to the site. There was no actual food and they all left. Curious, a couple
of my students spread out around town with FRS radios so they could see
perched crows. Then a bag of French fries was deliberately dumped. It
became clear that only the closest perched crows could actually see the food
resource, all the others which came were watching the other crows. Within 3
minutes there were 50+ crows and 20 gulls. Since they were doing science, I
made them do this experiment 3 more times, staking out different areas and
trying to set up visuals so they could track the flight of individuals.
Sure enough, the same thing happened, adjacent crows all were lured to a
site by watching the behavior of other crows. A couple of students who got
access to a local roof were able to watch the whole chain reaction event.
Now when I drive into Monroe I notice all the crows perched on rooftops and
utility poles and I smile because I am pretty sure I know why they are
there.

Rob Sandelin
Naturalist Writer, Teacher
Snohomish county.

_____

From: tweeters-bounces at mailman2.u.washington.edu
[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of Nathaniel
Peters
Sent: Monday, December 14, 2009 10:26 AM
To: tweeters at u.washington.edu
Subject: [Tweeters] Ice on Green Lake


Hi Tweeters,

I thought I would just share a rather odd experience I had yesterday while
on my run around Green Lake. With the recent cold weather a lot of ice had
accumulated on the lake, sometimes out as far as 150-200 feet or so from
shore. As I made my way around the lake, I noticed a number of Mallards
waddling around awkwardly and occasionally falling over on the ice. Hooded
Mergansers were out in force as well, though they stuck to the areas of
unfrozen water. At one point I scared up some Coots which attempted to run
across the ice while flapping their wings, and one of them was trying so
hard that he/she fell forward and proceeded to skid across the ice for about
15 feet....quite amusing!

The really surprising thing I noticed was as I was rounding the south end of
the lake where I noticed large numbers of crows flying overhead. As I
rounded the bend I noticed easily 150+ crows that were all hopping/poking
around out on the ice, about 100 feet out! They were pecking at bits and
pieces of material frozen in the ice and each had a beautiful mirror
reflection underneath it on the ice. I've seen birds out on ice before, but
not crows and not in that number!

Happy birding everyone!

-Nathaniel Peters
Seattle, WA
--
Nathaniel Peters
UW MCB/Genome Sciences - Berg Lab
ncpeters at uw.edu
Lab: (206) 543-1622
Cell: (931) 224-6154