Subject: [Tweeters] Bird population decline
Date: May 6 11:26:40 2008
From: Bob McMurtrie - bob at accutac.com


Hello Tweeters and Mr. Thompson,

I have some questions and I believe that you could be a big help in providing answers, which I greatly fear. My wife and I recently returned from a birding trip to the Tucson, AZ area which included Mt. Lemmon, Sabino Canyon and Madera Canyon and their various life zones. We were there previously in 1978 and 1982 when we saw a total of about 128 different species each time, and usually several individuals of many of them. This time we saw 38 different species, and a single individual for most of them. Five years ago there were major fires on Mt. Lemmon and in Madera Canyon, so obviously much of the understory and critters the birds feed on were destroyed. Some, but not many, of the trees were dead, but even the live ones had black, charred bark. Obviously the fires had an impact, but there were large areas where there had been no fire where there were almost no birds. And it's been five years.

Also, we have been going to Point Pelee, Ontario regularly (9 times since 1978) during spring migration, and saw well over 100 species with many individuals, until 1990 when the number dropped to 78, then gradually to 53 with most being single individuals in 2006. Others there, including Point Pelee people also commented on this. Granted, weather can control migration times to a degree (and produce fallouts), but I tracked all this with bar charts I made, so we weren't too far off track.

My basic question is: with apparent substantial loss of South American jungle winter habitat, windmill farms, tall buildings, fires, feral cats, crow predation, etc., are all of these things significant factors, or just a few? Have they been rated by severity? Are there other factors I'm not aware of? This situation, if real, is sad and scary, and I wonder if it can ever be corrected because the main cause seems to be human population growth.

We would greatly appreciate and respect your response.

Best regards,

Bob and Judy McMurtrie
Kirkland, Washington