[CT Birds] Common Birds in Decline in Connecticut
PCOMINS at audubon.org
Thu Jun 14 14:23:08 EDT 2007
These come primarily from an analysis of the Breeding Bird Survey data, which comes from randomly selected routes that are a sample of the state as a whole. Considering the declines I have seen in meadowlarks, thrashers and Prairie Warblers over the last 15 or so years, I am not surprised at all by these results. The one exception is Ruffed Grouse, which comes from Christmas Bird Count data for CT and RI. Each of these species, with the possible exception of Baltimore Oriole, is showing substantial declines on the Summer Bird Count, which wasn't taken into account beause it is a shorter term study. In the case of Orioles, looking at the BBS trends over the same period as we have for SBC, the trend isn't all that clear, but when you compare today's number with those of the 60's, the declines are quite apparent:
Some of the other species:
For each of these species the P values are 0.00 on the analysis, which means that there is very little chance that the trend is the result of a random anomoly.
Additionally, these trends math up well with the national trends for these species from BBS, where you would expect that the margin for error would be less because of the larger sample size. As you would expect the declines are greater for the most part in CT, because suburbanization and succession are happening here at a greater clip than other parts of the country.
There are a host of other common bird species showing declines in Connecticut that we did not select as our focal species, but that are also undergoing declines, including:
Northern Bobwhite (extirpated), Black-billed Cuckoo, American Kestrel, Evening Grosbeak (winter), Field Sparrow, Herring Gull, Blue Jay, Eastern Towhee and Song Sparrow. The common theme for most of them are early successional habitats.
I will also forward you the methodology paper.
From: ctbirds-bounces at lists.ctbirding.org on behalf of Ross Geredien/Good Migrations
Sent: Thu 6/14/2007 1:38 PM
To: ctbirds at lists.ctbirding.org
Subject: Re: [CT Birds] Common Birds in Decline in Connecticut
I need to inquire here as to how these numbers were determined? What data are they based on? If we think about a 99% decline, that means that in 1967 there would have been 100 meadowlarks for every one that are in the state today. And for every Baltimore Oriole in state today, five would have been present in 1967. Have people who have been birding in the state since 1967 noticed whether such dramatic declines are in fact palpable?
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