*
Dr. Ralph Morris asked me to post this important message on his behalf.
Common Tern Information Sought.*
Common Terns are in trouble on the Great Lakes. Overall numbers have
declined from 11, 189 pairs in 1977/78 to 9,049 pairs in 1998/99, the
last year of a total lakes census by personnel of the CWS and the USFWS.
The heaviest losses over this time period (-49%) have been in Canadian
waters of the lakes, while colonies in U.S. waters have increased by 12%.
Locally, the largest Common Tern colony on Lake Erie was on the east leg
of the Port Colborne breakwater where 1,311 pairs were counted breeding
in 1987. However, since 2004, no eggs have hatched among the few dozen
pairs that nested there each year and the site was totally abandoned by
terns in 2008. I believe most of these birds now nest on breakwaters in
Buffalo Harbour. The primary reason for losses in numbers of breeding
pairs is competition for nesting space with Ring-billed Gulls who arrive
and begin nesting about one month before terns arrive from
over-wintering grounds.
Biologists working at sites on the lower Great Lakes (Ontario and Erie)
believe that Common Terns arrived at their breeding colonies later than
usual this spring, and in fewer numbers. CWS personnel are currently
censusing waterbird numbers on the upper Great Lakes and will report on
the situation with Common Terns later in the summer. In the meantime,
I'm curious to hear from OFO members about comparative observations of
terns this year compared to earlier years (arrival dates and numbers at
colonies that members are familiar with).
Please forward pertinent comments to Ralph Morris at [EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>
--
John Black
President
Ontario Field Ornithologists
[EMAIL PROTECTED]
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