Subject: RE-BTPI + Neotropical migrants
Date: Mar 10 12:26:59 1995
From: Jerry Tangren - Jerry_Tangren at tfrec.ncw.net
>Re Jennifer Seavey's BTPI discussion:
>
>Yeow, she wasn't kidding. Here are the BBS trends for WA and OR:
>
>State Period Trend n sig.
>OR 1982-1991 -14.7 19 p<.01
>OR 1966-1991 -3.2 21 p<.01
>WA 1982-1991 +.7 21 none
>WA 1966-1991 -3.5 23 p<.1
>
>The trend is expressed as % annual change using a formula similar to that
>for calculating compounding interest. n is the number of BBS routes from
>which the trend was calculated. The authors warn against using data for
>species where n<14. p is the significance of the trend, from testing the
>hypothesis that the trend is actually 0. The source is an untitled,
>unpublished report from Bruce Peterjohn for USFWS/NBS biologists.
>
>____________________________
>Mike Smith
>Univ. of Washington, Seattle
>whimbrel at u.washington.edu
>http://salmo.cqs.washington.edu/~wagap/mike.html
Despite the presence of BPTI's at feeders, these birds are under tremendous
pressure from loss of habitat, both their coniferous and oak homes. These
areas all along the Pacific Coast are being developed as senior citizens
move out of the cities into smaller retirement communities, as businesses
move from southern California to northern california, Oregon and Washington,
and as there are more of us who want to live in more suburban settings with
larger yards.
Although they can clean up a feeder almost as fas as vacuum cleaner does not
mean the habitat requirements of the population as they existed in the
recent past can be met by replacment with human maintained feeders. These
birds apparently just require too much.
However, I find the numbers Mike posted rather comforting however, because
the drop so far probably does not match the loss in habitat. If we expect to
develop wildlife habitat for homes and businesses, we should EXPECT to see
drops in wildlife numbers.
Getting back to another discussion, this I believe is an underplayed issue
in the hot topic on Neotropical migrants. My personal belief is that much of
the loss in the eastern United States can be tied to a change in life
styles. People are moving out of the big cities. The average person now
takes up more developed land than did his parents. We demand a minimum of a
quarter acre for our homes, we demand malls with spacious shopping, and we
want it out in the "country."
--Jerry Tangren