[EBB Sightings] Band-tailed Pigeon

On Thu, 26 Jan 2006 12:56:29 -0800, Martha H Breed 
wrote:

>Aren't their numbers declining due to habitat
>loss in California?

I can find no evidence that their numbers are declining in California or
that there has been evident habitat loss.  You can get historical Christmas
Bird Count data at:

http://www.audubon.org/bird/cbc/hr/index.html

Using that site I created a graph showing Band-tailed abundance per party
hour in California.  Except for a bizarre spike in 1946, numbers have
remain relatively flat since the 1940's. 

The species is said to be dependent on acorns which are subject to periodic
fluctuations.  In years in which the acorn crop fails after several years
of acorn abundance, large flocks of Band-tailed Pigeons may move into new
areas in search of food.  At such times they often reach the floor of the
Central Valley where they are forced to eat such things as Mistletoe
berries.   

-- 
Joseph Morlan, Pacifica, CA 94044  jmorlan (at) ccsf.edu 
Birding Classes start Feb 7 in SF  http://fog.ccsf.edu/~jmorlan/
California Bird Records Committee  http://www.wfo-cbrc.org/cbrc/