Monday, February 29, 2016

Winter Bird Population Survey 2015-2016

The 24th year of RRBO's Winter Bird Population Survey has been completed.

After two brutally cold winters, this one was much milder, less snowy, and generally more pleasant. Surveys were conducted on 13 days (one day fewer than the mean) and a little over 20 hours total (lower than the mean of 28). Access restrictions continued this year. I was unable to survey anywhere along the Rouge River from Fair Lane Estate south due to it being fenced off for continued riverbank restoration. Thus, no Belted Kingfishers or Rock Pigeons were recorded (for the latter, the first time in 24 years). Only a few herons, and not many waterfowl were counted. Heavy construction activity continued along Fair Lane Drive for the new science building, impacting bird activity along eastern edge of survey area.
Nonetheless, the 38 species tallied was right on average. Two new species for the survey were recorded: Sandhill Crane and Wood Duck. These early migrants came at the very end of the season following a very warm weekend with southerly winds. These bring the cumulative total for the survey to 77 species.

Other uncommon species included a Bald Eagle; this adult bird was first seen in late December and continued to be spotted throughout the count period along the Rouge River (mostly on the south end of campus and along the concrete channel) but was only seen on one survey day. Although eagles are almost annual here, it was only the second time one has been recorded on this survey. A (singing!) Fox Sparrow early in the survey period was the third recorded for the survey. One or two American Crows were found on 4 survey dates. These birds were at the far north end of the campus.

At the other end of the spectrum, 7 species were found on all 13 survey days. In descending order of abundance they were: House Sparrow, House Finch, Northern Cardinal, Blue Jay, Black-capped Chickadee, Downy Woodpecker, and White-breasted Nuthatch -- all feeder birds. House Finches and House Sparrows were recorded in numbers well above average. For House Finches it was a record year, with a 127% increase from average.

Once again fruit-eating birds were largely absent. Three Cedar Waxwings on the first survey day were the only ones of the season. No Hermit Thrushes or Yellow-rumped Warblers were recorded. American Robins were counted, when present, in single digits most of the period. Last year robins were generally scarce on regional winter bird counts. This winter numbers of robins reported to eBird in southeast Michigan were much higher than last winter.  This suggests that the removal of fruit-bearing non-native trees and shrubs that is being undertaken by the university the past few years has had an impact on these numbers. This seems to be substantiated by data recorded this year showing that only 30% of the robins recorded were in areas where this type of vegetation removal had taken place.

For all the numbers from this year you can visit the RRBO web site. The page includes past counts and the history and methodology of the survey. 

Tuesday, January 12, 2016

Dearborn portion of Detroit River CBC, 2016

The Detroit River Michigan-Ontario Christmas Bird Count was held, as it is each year, on January 1. This was the 38th year for the count, which is centered at I-94 and Warren Ave, and the 22nd year that RRBO has coordinated the field work in the city of Dearborn.

After a record warm December, the new year came in cold (27-35F), breezy, and with snow flurries all day long. Water was still open, so waterfowl was not only not concentrated, but apparently largely elsewhere.  The Rouge River at the Ford Rouge complex usually has a decent variety of diving ducks, but not this year. However, there were two Lesser Black-backed Gulls there; one there last year was the first on the count. Seven Great Black-backed Gulls were also present. This is a pretty average number now for a species that used to be rare in the Great Lakes. The complex is also an unusual but annual wintering spot for Black-crowned Night-herons. There were 22 counted this year, a little above the average of 19.2 for the previous 10 years. Peregrine Falcons have become nearly annual on the Dearborn portion of this count, and this year's was found at the complex as well.

After some issues the last couple of years, personnel was re-jiggered to make sure the UM-D campus habitat was well covered. The snow and wind made small birds hard to find, and in general nothing notable was found. The west side of the river across from campus was also thoroughly searched, and you can read about that section with some great photos of a hybrid Mallard x American Black Duck and robins eating privet at Into the Woods and Elsewhere.

A personal issue sidelined one participant, and left most sunflower/wildflower fields uncounted and some other routes in the city uncovered. Only one major field had standing sunflowers, though, the one in front of Ford World Headquarters at Michigan Avenue and Mercury. It got a quick once-over, and the count’s third Merlin was found there.

Merlin. Photo copyrighted, no use without permission.

Pine Siskins have only been recorded on four counts, so 14 at a west Dearborn feeder was a good find.  An adult Bald Eagle has been seen around the river several times, but didn't show up on count day. It was found on January 2 for a "count week" species. Red-breasted Nuthatches have been very scarce the last couple of winters, but one has been seen regularly in the Springwells Park neighborhood. Unfortunately, it was last seen sometime around Christmas.

Everyone familiar with this count and our winter bird surveys knows that Dearborn has not seen its American Crow population recover since it was decimated by West Nile Virus -- my most recent summary is here. Last year it finally happened: no crows for the first time in the history of the count. This year there were also no crows counted.

We ended the day with 37 pecies, which is a record low. No new species this year keeps the cumulative species count for the Dearborn portion of this CBC at 88.

The complete results of the Dearborn portion of the Detroit River CBC can be found at the RRBO web site, which includes historical results.

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.