[Tweeters] Heron and frog

Kristin Stewart kristinstewart01 at comcast.net
Sun Mar 28 21:53:25 PDT 2010


Two or three years ago, I met Rachel Lawson and Rebecca Evans at Nisqually
NWR. We were wandering along on the trail to McAlister Creek, and watched a
Great Blue Heron catch a vole. We all thought it was a very LARGE vole, and
the GBH spent ever so much time trying to manipulate, or mandipulate the
vole into position to swallow it. It took quite a long time, perhaps more
than 5 minutes. It finally got the vole in a position to swallow it, the
poor vole kicking all the way, and we all thought that would be enough food
for some time for this GBH. What did we know? Not much apparently, as the
same GBH proceeded to catch yet another quite chubby vole about 2 minutes
later and 10 feet further along the way. My very first sighting of a GBH
prey catching episode was about 25 years ago also at Nisqually NWR, when I
saw a GBH catch what I thought at the time was a mouse, but now suspect was
a vole, which it proceeded to dunk into the water before attempting to
swallow it. Isn't Nisqually a great place?



Kristin Stewart

Olympia

kristinstewart01 at comcast.net

_____

From: tweeters-bounces at mailman2.u.washington.edu
[mailto:tweeters-bounces at mailman2.u.washington.edu] On Behalf Of
Guttman,Burt
Sent: Sunday, March 28, 2010 8:33 PM
To: Dennis Paulson
Cc: TWEETERS
Subject: [Tweeters] Heron and frog



In response to my tale of the heron and the frog, Dennis Paulson wrote, "I
wonder if the frog was alive. Herons and other birds that eat relatively
large prey very often spend quite a bit of time manipulating (and
mandibulating) their prey, and I have always thought this was to kill it or
at least greatly reduce its squirmability." I did wonder about that. The
heron was squeezing the frog quite a lot with its powerful bill, and it may
very well have been crushing the frog's guts, maybe even stopping its heart.
Early in the battle, as the heron sometimes dipped the frog in the water,
the frog seemed to kick a little as if trying to get away, but by the time
the battle was over it was moving very little, if at all. This is an
interesting question, and if anyone knows anything more about the details of
feeding by herons or other birds that eat large animals, I'd love to hear
about it. I've checked the books on my shelf that might be relevant and
find nothing, though John Terres (Audubon Encyclopedia of N. A. Birds) notes
that birds sometimes choke to death by trying to swallow something too large
and that herons have done it by trying to swallow too-large fish.



Burt Guttman

The Evergreen State College

Olympia, WA 98505 <mailto:guttmanb at evergreen.edu>
guttmanb at evergreen.edu

Home: 7334 Holmes Island Road S. E., Olympia, 98503



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