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All:
I agree with Blake's analysis: I've found Boreal Chickadeess still quite common
in dam
coastal sopruce woods although, from a longer perspective, they were once
common in inland spruce woods, particularly low-lying Black Spruce arees. There
is no doubt that both they and Gray Jays have declined over the decades.
Questions are often asked on naturens about changes in numbers of one bird
species or another. For those who want a perspective on the changes in many of
our birds might keep in mind that the web-available Christmas Bird Counts and
Breeding Bird Surveys offer much to think about. These are easily accessed on
the web, and for Nova Scotia CBCS specifically at:
http://www.audubon.org/bird/cbc/hr/index.html
You can choose species and locality and bring out a graph or table. Measuring
the rates of decline will require some statistical analysis - approximate with
such flawed raw data.
For the BBS, a very informative version for Nova Scotia is at:
http://www.mbr-pwrc.usgs.gov/cgi-bin/atlasa99.pl?NS%20&2&05
The table gives rates of decline measured with some care for statistical issues.
If you click on the bird names at left, you'll get more easily grasped graphical
outputs. As you will see, both Gray Jays and Boreal Chickadees have declined
severly overall in both BBSs and CBCs. This began before "global change" was in
everyone's minds, and might be related to forestry practices away from the
non-commercial (and partly protected) coastal stands.
Cheers, Ian McLaren
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