Subject: [Tweeters] Finches Eating from Road Surfaces
Date: Jul 21 17:32:25 2010
From: Kelly Cassidy - lostriver at completebbs.com


I think Richard Carlson is most likely correct. It's probably no
coincidence that finches, which tend to be among the most herbivorous of
birds, are most likely to be seen foraging on road sides or campfire ashes.
Plants, with a few exceptions, have very little sodium and animals must have
sodium. Animals that eat other animals can get sodium from the animals they
eat, but animals eating only plants have to get sodium from some other
source, like sodium concentrated after evaporation of droplets or puddles,
salt licks, etc. Even if the road was not salted, I would guess that
puddles of evaporating water on the dark, warm road surface leave salty
residues on the gravel. Sounds like a good research question (if someone
hasn't already looked into it).



Kelly Cassidy