[SBB] Conventional Wisdom -- Version 25 Jun 2007

[Bill Bousman <[[email protected]]>]

Folks:

I think Paul Ehrlich has said that we are involved in the largest 
uncontrolled biological experiment in history.  So, do not become too 
excited at these responses to two recent questions.

First, birds that winter here are not always fit to return north to 
breed.  Some are injured or in other ways deficient and although we 
have no idea what their thoughts are, they remain with us through the 
summer and in some cases for many years.  For waterfowl, some of us 
refer to various spots in the South Bay as "infirmaries."  One of 
these places is outer Guadalupe Slough, which is not accessible by 
mere mortals, but often has obviously injured birds oversummering 
there.  Another spot is Shoreline Lake, which has had various numbers 
of Surf Scoters that oversummer there over the last 10 or 15 
years.  Some of these have been obviously injured birds and if you 
study them long enough, they may flap their wings and you will see 
that they are lacking wing feathers on one side or the other.  But 
others seem okay and are capable of strong flight.  I've not checked 
the records, but we have had a male Greater Scaup there as well over 
the last 5 or so years (although I think he has now gone to his 
reward).  Do these birds breed?  It's debatable.  Grinnell has said 
that breeding by Lesser Scaup in the San Francisco Bay area in the 
first half of the 20th century was from crippled birds, but despite 
his claim, none of the original published reports indicated any 
injuries.  The answer, of course, is to be good observers and report 
what you see, and maybe the conventional wisdom will advance a bit.

Second, do Purple Finches breed away from the Santa Cruz Mountains 
and the Diablo Range?  Of course not.  Conventional wisdom is very 
clear that they restrict their breeding to more mesic areas at higher 
elevations.  But contrary to the old CW a few birds have started to 
nest in the past year or two in Cuesta Park in Mountain View.  Again, 
keep your eyes open so that we can document some new conventional 
wisdom for future generations to sink their teeth into.

Bill Bousman
Santa Clara County records compiler 



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