Tuesday, February 22, 2011

Winter Bird Population Survey 2010-2011

The 19th year of RRBO's Winter Bird Population Survey has been completed. Over the 20 December to 20 February survey period, 44 species were tallied. The previous annual average number of species is 38. There was a new species for the count this year, Tundra Swan, bringing the cumulative total over the years to 70 species. This is only the second year in which we have recorded Red-shouldered Hawk. Although only seen during one survey, the bird was observed several times throughout the period. A small number of Common Redpolls were recorded on three occasions late in the count period. One species that has been showing a dramatic trend is American Crow. The average number of crows counted per year from 1993-2002 was 139. Then West Nile Virus (WNV) entered our region and greatly reduced their numbers. In Dearborn and much of Wayne County, their numbers have not recovered. The average number of crows counted per year since then has been just 9. That number represents the cumulative number of crows counted over an average of 13 surveys days per year. Over the past decade, crows are often not seen on any given survey day, and the average number of crows per visit has been under 1.0 since 2004. This year it was 1.5, mostly owing to a flock that flew over campus on 1 January, the day of the Christmas Bird Count. Thus, that modest increase probably does not really represent a solid gain in numbers. The graph below tells the sad story. Another species that people were concerned was impacted by WNV was the Black-capped Chickadee. I last reviewed their status in 2002 and 2003. Our data showed a long-term decline that preceded WNV in our area, but this decline seemed to become more pronounced and numbers stayed depressed after WNV became established here. One interesting aspect of chickadee ecology is that every so often, very large numbers of young birds come south in the fall after a year of high productivity in the north. This phenomena occurred in fall 2010. It was much more pronounced east of here, even as closely as across the Detroit River in Canada. At Ontario's Long Point Bird Observatory along the north shore of Lake Erie, the number of chickadees banded over a few days in November exceeded any annual totals for the past 50 years! The ended up banding nearly 2000 chickadees, almost 25% of their 50-year total. Numbers here were nowhere near as remarkable, but they were noticeable here on campus during fall banding and evident in our winter survey numbers. The cumulative total of 355 chickadees during the survey period was the highest since RRBO counted 417 in 1995-1996, and the second highest total ever. The average number of chickadees per visit was the highest since 1998. Here's the graph: For resident species like crows and chickadees, this type of long-term data set in invaluable in seeing how birds react to various environmental changes, including diseases like WNV. It's critical to have monitoring programs like this in place, ready to provide "before" data when some unanticipated natural event occurs. Next year, after our 20th annual survey, I will be doing some more serious analyses on our data set, with an eye towards publication. Now, on to spring surveys...

Tuesday, January 4, 2011

Dearborn portion of the Detroit River CBC, 2011

The Detroit River Michigan-Ontario Christmas Bird Count was held, as it is each year, on January 1. This was the 34th year for the count, which is centered at I-94 and Warren Ave, and the 17th year that RRBO has coordinated the field work in the city of Dearborn. Our expectations were kind of modest. Temperatures had been mostly below freezing much of December, until a few days before the count. A lot of the Rouge River was frozen, and much of the Detroit River was also frozen, or flowing slush ice. This resulted in most gulls and waterfowl moving out of Dearborn. New Year's Eve was warm and it rained much of the night, continuing periodically in the morning on count day, followed by wind and falling temperatures. The number of hours in the field was diminished by both these conditions and the fact that both Michigan State and U of M were in bowl games, causing some early attrition among observers. In spite of this, 45 species were found in Dearborn, only slightly off the average of 47. For the first year, Ring-billed Gulls were missed in the city. However, we had high counts for Red-breasted Nuthatch (10) and White-breasted Nuthatch (36). Ember the Peregrine was found by my husband and I on one of her usual perches at Fairlane Plaza in the morning, and I later saw her on top of Ford World Headquarters. Our territory includes counting the bird in the various plantings on Ford properties. For some years, they were all sunflowers and attracted many thousands of birds. The last couple of years only one field has been entirely sunflowers, some have been wildflowers (but mowed in fall) and others were cropped in timothy hay and once harvested left barren. This year the wildflowers weren't mowed and the hay fields had sunflowers around the borders, although the cover crop was of no interest to birds. The best field was the sunflowers around the world headquarters: That's the headquarters building in the background between the trees. Although blackbirds has really worked these sunflowers over in the fall, there were still seeds in the centers of the heads. Over 100 Red-winged Blackbirds and a couple of Brown-headed Cowbirds were present, along with hoards of finches and other seed-eaters. It takes a few hours to get accurate counts on the thousands of birds moving in and out of the crop and a brushy line of trees in the middle. We also usually walk the concrete channel of the Rouge River. My husband Darrin O'Brien covered it this year. Here is another shot of the Ford headquarters, this time from a mile or so away along the channel: Snow Woods is another Ford property we cover. Here I am, dwarfed by a big tangle of grape, creeper, and Japanese honeysuckle vines. Although it looked perfect hideaway, there was no Northern Saw-whet Owl in residence. Probably one of the most interesting things on our count is the high number of wintering Black-crowned Night-herons. Around 2004, a winter roost was discovered inside the sprawling, mega-industrial Ford River Rouge complex, which is surveyed with special permission. The herons, which are not happy-looking birds in any circumstance, gather in what appears to be glum silence in thick Phagmites rimming a pretty nasty-looking small pond. It's near one of the blast furnace buildings, so maybe it stays open because it's receiving warm water somehow. Since 2004, the average number of night-herons here has been 24, and there were 25 this year. I'm sure a bunch are not counted that are hidden in the reeds. It's a very weird, post-apocolyptic-flavored experience seeing them there. I'm not sure what they find to eat. The boat slip and turning basin that you can see to the right of the "heron pond" in the photo below are deep, made to accommodate freighters. The channelized portion of the river leading into the basin is vee-shaped, so it freezes along the margins. Whatever they find, it is highly likely to be contaminated. It's just a weird situation! Finally,we had a new generation participating in the count. Greg Norwood did his first Dearborn CBC in 1997, when he was still a few years away from getting his driver's license. This year, he brought along his daughter Ruth, and his wife Terry documented the occasion. Althought this makes me feel really old, it's great to be part of a family tradition!

Wednesday, December 15, 2010

An update on Ember

My last post described how we found the identity of the Peregrine Falcon hanging around at the Fairlane Plaza South building at Hubbard Drive and Southfield. From her unique combination of leg bands, we determined that this bird's name is Ember, a female Peregrine hatched in April 2010 in a nest box on a smokestack at the Louisville Gas and Electric (LG&E) Mill Creek Generating Station, a coal-fired power plant along the Ohio River just south of Louisville, Kentucky.

I ended up hearing from Kate Heyden, an avian biologist with the Kentucky Department of Fish and Wildlife Resources. She handles the Peregrine monitoring in the state, and was the person who banded Ember as a nestling!

Kate generously sent along these cool photos from Ember's "early days."

Here is Ember being banded on 5 May 2010. Photo courtesy
Kentucky Department of Fish and Wildlife Resources.

Here she is with two of her siblings (I'm not sure which one of the three is her), along with the female parent on the right, about a week later at the nest site. Amazing how quickly they mature -- the chicks now have much of their white down replaced by adult-looking feathers. Photo courtesy Kentucky Department of Fish and Wildlife Resources.

My last report of a sighting of Ember was on 8 December, but it's likely she is still around. I also had a report from someone else in the building that they believe they saw a bird with different colored bands, so another Peregrine may be present. Stay tuned!

Tuesday, November 16, 2010

Ember: Kentucky Peregrine moves to Dearborn

Peregrine Falcons have been seen regularly in Dearborn since 1991, and have been reported annually since 2000. Up until a few years ago, their regular haunts included the Ford Rouge Plant, the concrete channel of the Rouge River, and the Ford Test Track.

Since 2005, Peregrines have been most often seen in an area roughly bounded by Ford Road and Michigan Avenue, the Southfield Freeway and Mercury Drive (outlined in red on the map below, or in the vicinity of this marker).

This area has several appealing features, from the point of view of Peregrines. It has several of the sunflower/wildflower/crop fields planted by Ford, which attract a lot of birds, and it has a half-dozen tall buildings that are often favored by the falcons. One group in particular has been a hang-out for one and sometimes two Peregrines nearly every winter since 2005: Fairlane Plaza South (highlighted in yellow in the map above). It's the home of Ford Motor Land Development, the real estate subsidiary of Ford Motor Co. UM-Dearborn alum and former bird bander Tim Endlein first alerted me to these visitors, and has kept me posted ever since.

Getting a close look at a Peregrine is not easy. For example, the one that spent last winter in Dearborn on the Village Plaza building at Michigan and Outer Drive usually sat on a blind ledge, high up on the building. But the Fairlane Plaza birds often perch on the office window ledges. In 2007, I got this photo third-hand of an office-peeper:

One or possibly two Peregrines once again appeared in late summer at Fairlane Plaza, again sometimes seen on a window ledge.

These photos are frustrating, because the legs of the falcon are not readily visible. Many of the Peregrines in the region are banded with a unique combination of color bands that allow identification of individual birds. Beginning in the late 1970s, a large, cooperative effort to help this species recover from population declines due to DDT was launched. Hundreds of Peregrines were released in the Midwest, and the species is still intensively monitored. The Midwest Peregrine Society brings together many resources in the region.

After letting the Ford people know what to look for, and encouraging them to get a good photo of the legs of any Peregrine stopping by, I got this great shot:

The purple band is a standard U.S. Fish and Wildlife band which carries a nine-digit number. The band is purple to indicate this Peregrine was born in the wild. Since the etched band numbers are too hard to read from a distance, each bird gets a combination of color bands on the other leg with easily visible alpha-numeric codes. I was able to look up "black-over-red, 05 over H" in the Peregrine database.

Please meet Ember, a female Peregrine hatched in April 2010 in a nest box on a smokestack at the Louisville Gas and Electric (LG&E) Mill Creek Generating Station, a coal-fired power plant along the Ohio River just south of Louisville, Kentucky! This location is about 320 miles away from Dearborn.

Ember is the offspring of one of only about a dozen pairs of nesting Peregrines in Kentucky. LG&E has Peregrine nesting sites at several of their facilities as part of their environmental initiative. The Mill Creek nest box was put up in 2006, and began being used the following year. Ember's mother was unbanded (as was the female each year at the site). Her father may be banded, but this is unconfirmed. Ember has three siblings: males named Volt and Dakota, and a female named Phoenix.

Ember left her nest on 19 May 2010. The photo above was taken in late July. Ford people have reported seeing her (and her bands) as recently as a week or so ago. As far as I have been able to determine so far, these are the first reports of the whereabouts of Ember since she left the nest site.

The Ford folks also think there has been another bird present at times. And since Ember is a youngster, she is obviously not the bird that wintered in previous years. I think everyone is motivated to get a good look at the legs of any falcon that visits at their windowsill now, and if we confirm any additional birds, I'll post an update.

Many thanks to Tim Endlein, Liz Saeger, and others at Ford; Mike O'Leary of the Dearborn Police Department; Chris Becher and Barb Baldinger, Peregrine monitors for the Michigan Department of Natural Resources and Environment; and all the others who regularly report Peregrine sightings to me. For more information on the local Peregrine program, please visit the updates on the Macomb Audubon Society page.

Saturday, November 13, 2010

Fall banding 2010 wrap up

I have summarized the fall 2010 banding season at the RRBO web site.

Click here for a detailed account of the season, including photos, a table, and some graphs. The page of our most commonly banded birds has also been updated. You can view overviews of previous banding seasons on this page.