Friday, September 9, 2011


The Northern Waterthrush has larger regional populations than preliminary estimates
The Connecticut State of the Birds 2011 report contained a contribution from Bird Conservation Research, Inc. entitled State of the Forest Birds.  In this report we projected, based on our findings for eastern Connecticut and Rhode Island, the total populations of certain species.  Since the appearance of our contribution, we have completed computerization of all of our data and are now able to estimate with accuracy populations present during the years of our study.  Although our analyses are undergoing further refinement by using new features available in Distance 6.0, our population estimation software, we can now make the following comparisons between preliminary Connecticut projections and actual estimates based on all data.
 Yellow-bellied Sapsucker: projected– most common woodpecker in northwestern CT, actual– 20,968 vs. 11,958 for the Downy Woodpecker.

Acadian Flycatcher: projected– 10,000, actual– 10,413.

Least Flycatcher: projected– 3,000, actual– 4,281.

Black-billed Cuckoo: projected– 1,000, actual– 411–815 in differing years.

Yellow-billed Cuckoo: projected– 1,000, actual- 2,156-4,354 in differing years.

Common Raven: projected– 400, actual– 395.

Cerulean Warbler: projected- 6,000, actual– 6,105.

Black-throated Blue Warbler: projected– 10,000+, actual– 41,712.

Pine Warbler: projected– 20,000+, actual– 74,431.

Louisiana Waterthrush: projected– 20,000, actual– 23,337.

Northern Waterthrush: projected– 3,000, actual– 4,190.

Eastern Towhee: projected– approaching 100,000, actual– 64,196.

Differences between initially projected and actual numbers are largely attributable to eastern Connecticut not always serving as a good model for populations in the rest of the state. This was particularly true in the case of the towhee, which had high densities in eastern Connecticut and Rhode Island but low densities elsewhere.

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