Wednesday, January 4, 2012

Dearborn portion of the Detroit River CBC, 2012

The Detroit River Michigan-Ontario Christmas Bird Count was held, as it is each year, on January 1. This was the 35th year for the count, which is centered at I-94 and Warren Ave, and the 18th year that RRBO has coordinated the field work in the city of Dearborn.

The day began with mild temperatures which had been the hallmark of the autumn and winter season up to that point. All water was open, and there was (and had been for the most part) no snow cover. Waterfowl and seed-eating birds were dispersed far and wide. We'd seen an excellent fruit crop in late summer and fall, but most had been stripped by the time New Year's Day arrived.

We ended the day with 39 species, well below the average of 46 because the party covering the Ford Rouge Plant was denied access this year (not by Ford, but by the private security firm of another company). Thus, we missed a number of species of waterfowl and the two dozen or so Black-crowned Night-herons that typically roost in a small pond on the property.

Nonetheless, the day was not without highlights. Covering the UM-Dearborn campus, Greg Norwood found one of the Gray Catbirds first found on 20 December. This is a new species for the Dearborn portion of the count and brings the cumulative total to 87. A Sharp-shinned Hawk seen on 29 December couldn't be located, but is tallied as a "count week" species and is also new for the count. Greg also found the Yellow-bellied Sapsucker that has been hanging around for weeks. This is only the second time sapsucker has been found on the Dearborn portion of the count.

Darrin O'Brien and I covered the various plantings on Ford properties. Like last year, most of the seed-eating birds were found at the fields in front of Ford World Headquarters. Most numerous were House Finches (over 900) and House Sparrows (over 1800). The day's total of 1038 House Finches was a new high for the count. Many of the fields had a lot of standing water, making it harder for the little birds that like to forage on the ground. The total of 26 American Tree Sparrows was a new count low. Also present at Ford HQ was a Peregrine Falcon. It chased around a Red-tailed Hawk before landing on the Ford building.

Arrow points to grooming Peregrine.

Cathy Carroll turned up 18 Great Blue Herons along the concrete channel of the Rouge. Often this group of birds roosts along the river on campus, but forages all along the river. She also saw one of the seven American Kestrels in the city, which is a new high for the count.

Finally, only one American Crow was found all day. This is a new low, and represents a decade of counts with fewer than 20 crows (most years fewer than ten). The local population has simply not recovered from West Nile virus, and I am beginning to wonder if I will ever see new birds move in.

The complete results of the Dearborn portion of the 2011 Detroit River CBC can be found at the RRBO web site on this page, along with historical results. I've written summaries here at Net Results for the 2011, 2010 and 2009 counts.

You can read an analysis of the first 25 years of the overall count in this paper:

Craves, J. A., and J. A. Fowler, Jr. 2003. Twenty-five years of the Detroit River Michigan-Ontario Christmas Bird Count. (pdf) Ontario Birds 21:109-128.

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