Bob Mauritsen,

You asked about an easily accessible source of information on life span of
birds. Specifically American Crow and Black-capped Chickadee. I pulled The
Birder's Handbook; A field guide to the natural history of North American
Birds by Paul H. Ehrlich, David S. Dobkin and Darryl Wheye (Simon & Schuster,
Inc. New York London Toronto etc. 1988) off the shelf and on page 645 in a
table listing maximum recorded lifespans I found American Crow 14 yrs, 7
months. For Black-capped Chikadee they list 12 years, 5 months.
I highly recommend the publication. It's quite a good starting point for
researching varied topics. The price is very reasonable (I paid $ 14.95 for
the 785 page book back when it came out). I've seen it for sale at both the
Seattle Audubon Society Nature Store (8050 35th Avenue NE) or at Flora & Fauna
Bookstore (121 1st S underneath Key Bank near Pioneer Square).

Enjoy!
Martin Muller, Seattle
martinmuller at msn.com