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.

Spring migration 2011

The spring 2011 survey season took place 1 April through 15 June. On campus, regular surveys were conducted on on 50 of the 70 days, with nearly daily surveys between 20 April and 3 June. The surveys recorded 146 species (another 15 were recorded in Dearborn off-campus). This is greater than the previous ten-year average of 130 species, or the five-year average of 133. The peak day was 10 May with 95 species, of which 25 species were warblers. Typically, our peak day is around 80 species and occurs later in the month (May 16-20 the past three years).

Weather
Spring 2011 was the second wettest spring on record for Detroit, according to the National Weather Service. April was generally cool, with measurable precipitation 18 out of 30 days and a rainfall total 2.5 inches above normal. May featured normal temperatures, and 21 days of precipitation. This included a dramatic soaker on May 25-26 with over 2.5 inches of rain on campus that caused the Rouge River to peak at least five feet above flood stage (upper left in photo is the waterfall at Fair Lane Estate, inundated by the high water). The month ended up being the second wettest May on record.

Highlights
Thirty species of warblers were recorded on campus this spring. This includes all 26 regularly-occurring species (at least 8 of the last 10 years), as well as the less-common species Pine Warbler (26 Apr), Prothonotary Warbler (9 to 11 May), Kentucky Warbler (10 May), and Hooded Warbler (18 and 22 May).

In general, migration was excellent this year, which has not been the case for the past five years or so. In addition to great diversity, numbers were also better. Early season migrants were especially abundant. The two eBird graphs below show two of these species, Yellow-rumped Warbler and Palm Warbler for the last five spring migrations. Lines represent the highest count of a species submitted on a single checklist from the UM-Dearborn campus during the weekly periods indicated. They show peak numbers in 2011 were much higher than in recent years (click to enlarge).




A variety of things could factor into these increased numbers, but a couple stand out, especially for the high numbers of early migrants. First, this was a La Niña year. While La Niña/El Niño cycles do not have a strong impact on our weather here in the upper Midwest (which is more influenced by the North Atlantic Oscillation), it does have a strong impact on weather where many of "our" birds winter. Namely, it was a very wet winter in much of Latin America. Wetter winters tend to have higher insect abundance, which translates into better overwinter survival for some species of birds. Thus, some species may have been more abundant this year.

Another factor could be detectability. The overall cool weather, without early hot spells, slowed leaf-out on woody plants. When trees don't have leaves, birds are simply easier to see and count. The graph below shows the accumulated growing degree days (GDD) for the period of 15 March, when woody plants here often begin to awaken, and 10 May, when we would expect many migrant bird species to be present. GDD are a measure of heat accumulation based on daily temperatures that are often used in agriculture to determine, for example, when crop species are likely to mature (data from Detroit Metro airport, click to enlarge).

As you can see, by our peak day of 10 May, the accumulated GDDs were the lower than they had been for years, which was reflected in the slow leaf-out of the trees here on campus.
Other notable birds this spring included Osprey on 10 and 23 May; five records of Bald Eagle, of which three were on campus; five records of flyover Sandhill Cranes, all from campus (there have only been 10 records in the past 10 years!); and the spate of Bobolink sightings around Dearborn between 6 and 9 May which included ten singing males in the fields at Hubbard and Southfield on 8 May.

Arrival dates
Only two species arrived earlier than any previous record for Dearborn. They were Ruby-throated Hummingbird on 26 Apr (4 days earlier) and Indigo Bunting (27 Apr off-campus, 1 day earlier). A Blackburnian Warbler on 27 Apr tied the previous early arrival date. Two Common Loons seen over east Dearborn on 20 Mar were also early, but occasionally this species winters in the Great Lakes.

Extremes are interesting, but deviation from a more typical arrival date is probably a more accurate depiction of any shift in migratory phenology. I have 14 to 21 years of spring arrival dates for 43 species. There are a number of ways to calculate central tendency (or the "expected" middle value of a data set). For simplicity's sake in this example, I calculated the arithmetic mean, or average arrival date for each species to compare to this year's arrival dates. For these 43 species:

• Fourteen (32%) arrived on their average arrival date.


• Seven (16%) arrived later than average (the average for those species only was 3 days later)


• Twenty-two (51%) arrived earlier than their average arrival date (for those species, the average was 4 days earlier).


• For all 43 species, arrival time averaged 1.6 days earlier than "usual."

All spring data from 1994 through 2011 is now in eBird. You can explore all of the survey data input for the campus at eBird. Use the "Change date" button at the top of that page to look at separate years or to compare years.

Many thanks to Darrin O'Brien and Mike O'Leary, who assisted with surveys this spring.

NAMC 2011 - Dearborn portion

Saturday, May 14 was the North American Migration Count. My husband Darrin O'Brien coordinates the count for Wayne County, and as usual we covered the UM-Dearborn campus, as well as some other spots in Dearborn. It was a pretty lousy day weather-wise, and many of the migrants that we enjoyed last week had moved on. Although we were only able to thoroughly cover campus and one of the Ford fields (with quick peeks at a few other locations) we still managed to have a pretty good day. On campus we tallied 83 species, including 19 species of warblers. None of the warblers were recorded in numbers over 10 individuals, but we had great looks at Mourning Warblers which is always a treat. Most of the warblers were feeding rather high in oak trees, typical of mid-migration as they are among the last trees to leaf out. Other highlights included a flyover Broad-winged Hawk, and the first Gray-cheeked Thrush of the season. We spent more time than we budgeted at the Ford field in the southeast corner of Hubbard and Southfield. We ended up with 48 species there, including 13 warblers species feeding in the oaks along the margins. This field, along with several others, has been planted in a cover crop of clover. While the Bobolinks present there earlier this month have moved on, there were many Savannah Sparrows on territory or with nests, along with Ring-necked Pheasant, Eastern Towhee, and some lingering White-crowned Sparrows. One of the better birds of the day was a calling Eastern Meadowlark in field #8. This is no longer an easy bird to find in Dearborn. Please note that these fields are now posted "no trespassing" so should only be viewed from public roads. RRBO has permission from Ford security to survey them. One last surprise was a big roost of Double-crested Cormorants (above) at Fordson Island. Between the birds perched on the dead tree and the ones flying around the Ford Rouge Plant, we counted 102. Back at home in east Dearborn, we had one of the Pine Siskins nesting in the neighborhood. Unfortunately, we did not have the time to walk along the Rouge River channel, or hit a couple of other birdy spots. Overall, we had 98 species (23 warbler species) in Dearborn for the day.

Spring migration update

Spring migration has been terrific the last week, so I hope everyone has had a chance to get out and see some birds. I thought I would provide a more detailed update here.

The chart below shows the number of species seen on campus each day since 2 May (the yellow line) as well as the number of warblers species (the blue bars). Click to enlarge.

The best day of the season was 10 May, with 95 species recorded, 25 of which were warblers. For some perspective, there are 37 species of warblers that occur regularly in Michigan (4 more are considered accidental; we have recorded all but 2 of the 41 species in Dearborn in the last 40 years). Some of the warbler highlights were a Kentucky Warbler on 10 May, our first record since 2006 of this southern species, and a female Prothonotary Warbler, which was present from 9-11 May. A gorgeous Golden-winged Warbler was also seen from 10-12 May. Closely related Blue-winged Warblers have also been present, while on 8-9 May, a hybrid of the two, a "Brewster's" Warbler, was observed; it sang a Blue-winged song. The total number of warbler species for 2011 so far is 28.

Other bird highlights of this period include a Summer Tanager and an Osprey on 10 May; a fairly early Olive-sided Flycatcher on 12 May, and two Red-headed Woodpeckers on 13 May.

We have recorded 133 species on campus so far in 2011. The total for Dearborn for the year is 151. This includes two records of Clay-colored Sparrow. One was this bird, photographed by Cathy Carroll along the Rouge River near the TPC of Michigan on 10 May.

Another was singing at the fallow sunflower field at the south side of Hubbard at Southfield. That location also hosted up to 10 male Bobolinks from 6-8 May.

I think migration has been terrific due to a combination of things. First, we did not get the very early warm spells that we have had the last couple of years, so trees and shrubs did not leaf out early. This has made viewing conditions quite excellent. Cool mornings have concentrated birds in sunny spots in the morning, and also resulted in many insects being most abundant near the water's edge (on campus, along Fairlane Lake). Thus, birds have been easier to find. Some credit has to be given to the luck of weather patterns, which are always the wild card. Finally, I think we are recovering from population losses that were due to the dramatic cold spell in the eastern U.S. in spring 2007.

There is a lull right now, but I expect we will get one more good wave of migrants before the end of the month. Viewing conditions will be more challenging now that foliage is thicker, but do your best to get out and enjoy!

Update on the Ross's Goose

In my last post, I described the discovery of a Ross's Goose on 24 March 2011, a first record for Dearborn. The goose was banded, and we have just received the details from the Bird Banding Lab.

This was a nestling male banded on 7 August 2006 in Nunavut. This much I knew from reporting the goose on the Bird Banding Lab's web site. The location, it turns out, is McTavish Point. The geocoordinates are 67.75, -101.08333, which places it north of the Arctic Circle in the Queen Maud gulf region, where over 90% of the world's Ross's Geese nest.

This map (click to enlarge) shows the banding location with a red marker: this is 1900 miles in a straight line from Dearborn. I've also indicated the location of Akimiski Island in James Bay, Nunavut. Although we do not see many Canada Geese with orange neck collars around here any longer, this is where nearly all of them were banded (more on the Dearborn-Akimiski connection here).

Ross's Geese have undergone a substantial population increase in the last few decades, and while once exceedingly rare in the Midwest and eastern U.S. during migration and winter, they have been showing up in these regions with increasing frequency. The increase in Arctic-breeding geese (especially Snow Geese) has profound impacts on sensitive habitats. "Our" Ross's Goose was banded by Ray Alisauskas, a scientist with the Canadian Wildlife Service, one of the key researchers working on the status of Ross's Goose and Snow Goose and their impacts on Arctic ecosystems. (Thus answering the obvious question of who would be in such a remote place banding geese!)

Most of the specific information on the winter or migratory distribution of Ross's Geese based on band recoveries is from hunters. Presumably, a report like ours, from a live bird, is quite rare.

While not the flashiest bird, this Ross's Goose surely had one of the most interesting stories of any bird we have encountered!

New for Dearborn: Ross's Goose

In the late afternoon of 24 March, Jim Fowler, Jr. found an adult Ross's Goose on private property, a first record for Dearborn. Several of us were able to see the bird and get some photos, and were hopeful the bird would be present in a more accessible area the next day. Searches all over the city turned up empty, however.

The goose was in the company of three Canada Geese, and was approximately the size of a Mallard, perhaps slightly larger. In Mike O'Leary's first photo, the bird is relaxed and shows the short-necked appearance of a Ross's Goose (it later got a little wary and raised its head a lot). The feathering between the bill and face was very straight, and the base of the bill had the characteristic blue-gray color and the some of the warty bumps of a Ross's Goose. (These warts are most pronounced on older males, least on females.)

Looking at the bird with binoculars, no grin patch was readily apparent; in the close-ups of Cathy Carroll's photos below, a thin dark line is present. This seems to be within the range of an "acceptable" Ross's Goose. The forehead didn't appear as "steep" as some Ross's Goose photos I have seen, but is also within the range for Ross's. It was obviously not a Snow Goose, but many of these geese have been judged to be hybrids.

We all appreciated (and enjoyed!) Cathy's belly-crawl up to the goose for a few closer photos.


The last two are the same photo; I increased the contrast of the second photo.

Those of us who saw this goose feel pretty comfortable calling it a Ross's Goose, and not a hybrid with a Snow Goose. According to the Birds of North America account for Ross's Goose, the percentage of hybrid Ross's x Lesser Snow Goose was 1.9% between 1989 and 1992 (n=2,943 Ross’ Geese captured) during banding operations in central Canadian Arctic. This was down from 4.7% for the period between 1962 and 1968 (n=29,880). It sure seems like many more birds are called hybrids than are likely to be actually present in the population. Perhaps this speaks to our lack of ability to truly distinguish the species of some intermediate-looking birds.

A final clue is available that may corroborate the identity of this goose. It had a band on its left leg. We have several photos that show most of the numbers, and I have a call into the Bird Banding Lab to the person in charge of looking up partial band numbers.

UPDATE: We have confirmed that this is indeed a Ross's Goose, banded in Nunavut on 7 August 2006, a male of unknown age.

This is the 257th species for Dearborn. There are fewer than 6 records of Ross's Goose for Wayne County.

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Thanks to Joe Hildreth for his comment below noting that a banded Ross's Goose was seen in Bowling Green, OH from 13-19 March. The pitch of the forehead, feathering near the bill, and bill structure look strikingly similar to the Dearborn bird. There is a link in the comment to a couple of photos.

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...

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!

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!

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.

Super senior P. cyanea

One of the most interesting birds banded this season was not an unusual species, but an unusually old bird. Most small songbirds do not make it through their first year -- they have about an 80% mortality rate. If they make it through their youth, many only live 2 or 3 years. Resident birds tend to live longer than migrant birds, and the farther a bird must migrate each year, the more hazards it faces, and the shorter the typical lifespan.

Indigo Buntings nest over much of the eastern U.S., and winter in the West Indies and Central America, and are therefore considered long-distance migrants. This male Indigo Bunting was first banded as a "second year" bird on 23 August 2003. Thus, it was hatched in the summer of 2002. We recaptured it in May 2006 and May 2007 when it was in breeding condition. This many round trips is pretty remarkable itself.

We caught him again this past week, on 29 Sept. Based on the way age calculations of recaptured birds are made, this makes this bird 8 years and 3 months old -- which happens to be a longevity record for this species in North America, according to the longevity records kept by the Bird Banding Lab. The previous record was an 8-year-old bunting in West Virginia -- a record that stood for the last 48 years.


You can take a look at some of the other birds we have recaptured years after their original banding on this page at the RRBO site. Note that on that page, the "age" indicated is the period that has elapsed between captures, not a calculated age.

Cats eat bird eggs

One of the presentations I attended at an ornithological meeting earlier this year was "Cats and fat doves: resolving the urban nest predator paradox." The project is looking at nest predators in urban versus rural areas, and if and how they differ.

This particular study used Northern Mockingbirds in Florida as subjects. Mockingbirds are to Florida what American Robins are to Michigan as far as common nesting yard birds are concerned. The researchers located dozens of nests and put cameras on them. These cameras included the ability to monitor the nests at night.

Although Cooper's Hawks were present at all the urban sites, they are not major nest predators of mockingbirds in urban settings, but tend instead to eat abundant, profitable, and easy-to-catch prey -- usually doves and pigeons.

The main nest predator in urban/suburban areas, accounting for 70% of nest predation, was house cats (see this chart). This didn't surprise me, but just reinforced what we know about outdoor cats: they are extremely effective predators of birds and other small wildlife. Also not too surprising was that the surveillance showed that cats were very adept at climbing the trees and raiding the nests.

Yet two facets of the results were particularly interesting to me. When cats predated a mockingbird nest, 28.6% of the time it was to eat the eggs; the rest of the time it was the nestlings that were taken. Thus, the reproductive ability of the mockingbirds was destroyed.

The other aspect was that 94% of the cat predation took place at night.

So please, keep your cat indoors. This is especially critical during the breeding season and at night.

My cats Sophie and Juniper are strictly indoor cats. Everyone is happy: the cats, the birds, and us.

Update: Shortly after I wrote this, The Wildlife Society and the American Bird Conservancy put out a joint press release to remind people that this is a particularly critical time to keep cats indoors. You can read it here.

Spring 2010 migration in review

The spring 2010 survey season took place on 47 days between 1 April through 4 June. There were surveys on most mornings in April and nearly every day in May except during heavy rain. As in past years, each survey always included a 1.5-mile standard route in the natural area on campus. Many days, additional area was covered; distance, time, and birds counted on these legs were recorded separately but are discussed below in aggregate. On campus, 129 species were recorded (another 9 were recorded in Dearborn off-campus). This equals the previous 12-year mean. The peak calendar week was 16 through 22 May with 92 species. This is the same peak week as 2009, but last year 95 species were recorded that week. The peak day was 16 May (18 May last year) with 76 species (ten fewer than 2009). Weather The National Weather Service reported that 2010 had the warmest spring on record for Detroit, and the warmest spring since 1991 across most of the southern Michigan region. This was largely due to warm temperatures in March and April (both months in the top 20 warmest lists for southeast Michigan). The first week in April was particularly hot -- the warmest first week in April in climate history at Detroit, Flint, and Saginaw. However, there were below-average temperatures the second week in May. At Detroit much of the spring was dry, with precipitation well below average through the end of April. Rain in May helped boost precip levels up and much of the region was near-normal by the end of May. These weather patterns were guided by a jet stream that was generally south of our region up until May. General trends One inevitable result of warm weather early in the spring is that trees leaf out earlier, making detecting birds more difficult. While most spring birds are recorded by hearing them sing, this obviously doesn't work with silent birds, especially females. The understory here on campus is now dominated in most areas by non-native shrub genera that also tend to leaf out early: Lonicera (honeysuckles) and Rhamnus/Frangula (buckthorns). These hindrances to detectability may have played a role in overall low numbers of many species of migrants, and late season migrants in particular. Species that make up the caboose of spring migration here, such as both cuckoos and Blackpoll, Canada, and Mourning Warblers, were found only in very modest numbers over a period of just a few days. I hope that detectability, favorable weather promoting migration past our site, or some other benign factor was responsible for the lack of late-season migrants. We will probably never know if the burning of oil from the Deepwater Horizon catastrophe in the Gulf disoriented, sickened, or killed migrant songbirds. Whether it did or not, we can only wait and see how it effects southbound migrants, directly or indirectly. As of this writing, unknown thousands of barrels of oil are still belching from the sea floor. Right now, our minds are with the waterbirds, sea creatures, and humans that are being immediately and urgently impacted by these malignant plumes of oil. I'm sure we have yet to imagine the profound and far-reaching impacts this disaster will have on wildlife -- maybe even migrant songbirds -- in the years to come. Already troubling to me is the apparent decline in the number of individuals of some common species. Black-throated Blue Warbler, Black-and-white Warbler, American Redstart, and Ovenbird are good examples. The number of individuals of each of these species posted a greater than 30% decline over the average number counted the previous three years. This ranged from 33% fewer redstarts to 57% fewer Black-throated Blue Warblers. These numbers have not been adjusted for effort, but effort has been similar the past four years, hence the short time frame given. In a few more months, 17 years of daily spring surveys with effort data will be digitized and available for analysis, providing a much clearer picture. But even this back-of-the envelope calculation may be cause for alarm, as this suite of species has something in common: they all winter primarily in the West Indies. John Faaborg's excellent long-term winter banding project in Puerto Rico has noted very alarming declines in some of the most common wintering North American migrants on his study plot -- and both Black-and-white Warbler and Ovenbird have declined to less than 20% of their original abundances since 1973. Migrant birds have complex life histories, so it is hard to draw conclusions from one year and one place. If you are interested in the struggle to understand how to monitor and evaluate migratory songbirds, I recommend this excellent overview (PDF): Conserving migratory land birds in the New World: Do we know enough? Ecological Applications 20:398-418. You don't need a lot of technical chops in bird ecology to get the gist of what we are up against when you read this paper. You can help! There is power in large amounts of data. For this reason, I encourage all readers to consider contributing their past and future bird data to eBird. I believe this is our best hope for strong evidence to shape conservation of birds for decades to come. Back to spring 2010... Arrival dates Only a few species posted record early spring arrival dates this year. Blue-gray Gnatcatchers arrived on 8 April, four days earlier than the previous early date. On 15 April, a Blue-headed Vireo showed up, four days early. When they were recorded on 16 April, Chimney Swifts were two days early. I keep track of the arrival dates of over 40 species of conspicuous (easily detectable) migrant species. About half of these species arrived earlier this year than the previous 16-year mean (an average of 4 days earlier), while about half arrived later (average 3 days later). More interesting, perhaps, is comparing the 2010 arrival date with the mean for the first 7 years (for most species, 1993-1999). In 2010, 62% of species arrived earlier than they did during the early 1990s, an average of 5 days earlier. The 31% that arrived later did so on average of 3 days later. If we look at this group of species and compare the early period (for most species, 1993-1996) with the current period (2003-2010), the trend toward earlier arrivals is even more pronounced. Nearly 79% of species are arriving earlier (by an average of 4 days), while less than 17% are arriving later (3 days). This method uses arithmetic means, and more rigorous statistical testing over longer time periods will be done once digitization of all years of spring survey data is complete. Highlights Notable birds were rather few and far between this year. No outstanding rarities were recorded. A number of less common species were found on campus: Common Loon (flyover, 15 Apr), American Coot (7 Apr), Sandhill Crane (flyover, 5 May), Red-headed Woodpecker (5 May), White-eyed Vireo (25 and 30 May, probably the same bird), Hooded Warbler (6 and 21 May), Summer Tanager (14 and 19 May), and Orchard Oriole (1 May, and another bird that arrived on 23 May and was present through the end of May). Perhaps more notable were the birds not recorded. For the first time in 18 years, we did not record any Blue-winged Warblers, normally a common species. Other species that are annual here but were missed this year -- Philadelphia Vireo, Orange-crowned Warbler, and Connecticut Warbler -- can be difficult to find and have often been picked up during banding operations versus surveys. Because we do not currently have a spring research project that can be addressed by the capture of birds, we did not band birds again this spring and so did not record these species. Many thanks to Darrin O'Brien and Jerry Sadowski, who assisted with surveys this spring.

How to help baby birds

The calls have already started. "I found a baby bird. What should I do?"

The answer is nearly always: leave it alone.

The vast majority of these birds are not orphans. Invariably, the ones that are "rescued" by well-meaning people end up dying because the folks that bring them home are like the proverbial dog that caught the bumper. Once they catch it, they have no idea what to do with it.

It is perfectly normal for a baby bird to leave the nest before it can fly. Baby birds grow rapidly, with many species leaving their crowded nests inside of two weeks. They are awkward, not fully feathered, and cannot fly.

American Robins, for example, can't fly when they leave the nest and are often found bumbling around, apparently alone and helpless. However, even if they are on the ground, their parents are most likely tending to them. The parents may be off finding food, or just in hiding because they are more wary of you than the young ones are.

If the baby is in immediate danger of being stepped on, run over, etc., you can move it a short distance. It isn't true that the parents will abandon it if it has been touched by a human. Do not chase the baby bird all around trying to catch it. The stress can kill it. If it can evade you, it can likely evade a predator.

Sometimes a nest gets blown down in a storm. You can reconstruct a nest in a container with drainage (like a berry basket) and securely fasten it near the original site. Do not try to raise the young yourself, it is not only difficult, in the U.S., it is illegal to possess a native bird.

If the bird you find is truly abandoned, it may be that by the time you find it, it is already too late, especially if it is a very young, naked baby bird. If you must take in a baby bird --

1. Make sure it is a native species (see below). Many rehabbers will not take non-native species, and the release of non-native species is prohibited in some areas.
   
2. Put the bird in a covered, ventilated box lined with a folded towel. Put it in a quiet, warm place, away from pets and children. In case you were wondering, yes, there are diseases you or your pets can contract from wild birds.
3. Do NOT try to feed the bird or give it water. You can easily kill it.
4. Contact a licensed wildlife rehabilitator immediately (Google "wildlife rehabilitators" and your locality). Raising healthy baby birds takes nearly 24-hour specialized care and knowledge of the nutritional needs of each species at different ages. Sick birds are even more complicated. Again, under the Migratory Bird Treaty Act, it is illegal to possess a native bird without special permits.
   

The species you are likely to encounter are common, prolific, adaptable, and will have more than one brood of youngsters a year. Loss of eggs, nestlings, or fledglings is normal for all bird species and built into "the system."

A huge percentage of the calls I receive are for House Sparrows, European Starlings, or Rock Pigeons -- none of these are native to North America. It does not make ecological sense to spend time and resources "saving" these species, which are already overabundant. They are not protected under law by the Migratory Bird Treaty Act, and it may be/become illegal for these species to be rehabilitated and released into the wild.

It is not easy for many people to "let nature take its course," but it is nearly always the right thing to do.

Download RRBO's brochure on what to do if you find a baby bird (PDF).

Winter Bird Population Survey, Year 18

Last year I introduced readers to our annual Winter Bird Population Survey. I've just completed the 18th year of this survey, recording two new species.

The two new species were: Mute Swan (two birds flying over on 4 February), and a Long-eared Owl on 21 January. This brings the total cumulative species list to 69. The number of species that have been recorded in only one year is now 15, and the number of species that have been recorded every year is 21.

Every year since 2002, the year West Nile Virus was first detected in Michigan, I have lamented the loss and subsequent lack of recovery of American Crows. This winter, only a single crow was counted during the survey period. This is the seventh year in a row with fewer than 10 total counted on the survey. The average number of crows found over the survey period prior to WNV was 139; the mean since (2003-2010) is 7. I know of only two pairs of crows nesting in Dearborn. I don't know if these four birds have some sort of immunity to the virus, but I find them in the same place every year, and they don't seem to produce any surviving young.

Tufted Titmouse is another species that suffers high mortality from West Nile virus. They seem to have made a come-back in recent years, and this year the survey recorded the highest number since 2002.

Sparrows in general were seen in lower numbers this winter, but this could be due to the fact that the many of the Ford properties, which typically attract thousands of birds and which we tend to see a little overflow, were harvested bare this year.

American Robins were plentiful, as they have been most recent years. This is the eighth year in a row where they have been recorded on 75% or more of the survey dates (the survey period runs from 20 December to 20 February). The average number of robins seen on each visit has also been increasing, as the graph below indicates.

So long as robins are able to access some water (although they will eat snow) and have a supply of food (mostly fruit, but also invertebrates in leaf litter, so snow cover is a handicap), they'll stick around.

Other than those "highlights," it was a rather below average winter. I tallied 37 species, just one species below the average. Other parameters, such as individuals counted per hour or per visit, were also slightly below average, although not dramatically. However dull, long-term data like this is very important for detecting population trends and responses to climate change, habitat alteration, or pathogen introductions, as the robin and crow examples illustrate. And since this survey uses multiple visits over the winter season, it is more robust than one-day counts such as the Christmas Bird Count. In fact, it is probably the unsung hero among the many datasets RRBO has put together over the years.

You can view an introduction to how the Winter Bird Population Survey works, as well as all the results, on the RRBO web site.

How to detect ruffled feathers

One of my favorite non-bird books is The Songs of Insects, a fabulous guide to dozens of species of crickets, cicadas, and katydids. Photographer Wil Hershberger's web site has a page where he notes the presence of two small filoplumes on the napes of songbirds he'd photographed. Filoplumes are specialized feathers, long and hairlike, that are most numerous at the base of wing feathers. Special sensory cells at the base of filoplumes transmit information on the position and movement of wing feathers during flight. According to the Manual of Ornithology: Avian Structure and Function, many passerines also have filoplumes sticking out of their crown and nape, "perhaps warning the bird when wind disrupts the smooth outer surface of the plumage."

I found this incredibly intriguing, and when I had the time, I looked for these plumes on the birds I banded. Sure enough, there they were! I was able to find them on a variety of species, both male and female, and could even see them on some older head shots I had taken during previous fall banding seasons. Although not particularly easy to photograph (especially with one hand!), here is a little slide show of some of my shots. Look at the back of the neck -- you might have to slow the speed down a bit or pause on some photos. (Note: apparently some Firefox users cannot see the Flickr slide show, a known bug with Flickr. If you have a Flickr account, it might help to log in.)

Species in order: Yellow Warbler (male then female), Orchard Oriole, Black-and-white Warbler, Brown Thrasher, White-throated Sparrow, Tennessee Warbler, Magnolia Warbler, Rose-breasted Grosbeak (male then female), Black-thr Green Warbler, Connecticut Warbler, Golden-winged Warbler, Nashville Warbler, Purple Finch, Wilson's Warbler, Baltimore Oriole, Common Yellowthroat. Created with Paul's flickrSLiDR.

A 1989 paper (pdf) in the Condor, the journal of the Cooper Ornithological Society, described the presence of these protruding filoplumes on the napes of many passerine species. The authors noted that species which lacked these plumes had dense, stiff feathering on their napes, while species that displayed the filoplumes had softer and more flexible feathering in this area. They also concluded that these plumes served to detect disturbances in the feathers in an area that birds could neither see nor reach. The looser plumage might have less insulative properties to begin with, and unnoticed disheveled plumage might make a bird even more vulnerable to heat loss. A quick shake or perhaps scratch of the head, or facing into the wind can smooth the feathers once again, correcting the situation.

It's hard to believe I handled tens of thousands of birds -- with part of the routine being close scrutiny of plumage -- without making particular note of this interesting characteristic!

Peregrine wintering in Dearborn

Wintering Peregrine Falcons are not unusual in Dearborn. Most years we have at least one sighting, and one has wintered every year for the past five years. Since Ford began planting sunflowers and other crops at their local properties, this has been the most common place to find them (Merlins, too). The Ford Rouge Plant has also been another Peregrine "hot spot."

This winter we have a Peregrine in a new location. On January 4, Dearborn police officer and long-time RRBO volunteer Mike O'Leary found a Peregrine at the Village Plaza, the tallest building on the west side of Outer Drive just north of Michigan Avenue. The "A" marker on the map below is the intersection of Michigan and Outer Drive. The red arrow points to the Village Plaza building. Enter off Michigan Avenue, past the sub shop, via the street marked in green on the map.

The Peregrine has been hunting around the building and the adjacent golf course. It likes to hang out on the concrete ledge on the southwest corner of the building. The arrow in the photo below shows where it especially likes to sit.

Believe it or not, the bird is in this photo at the tip of the arrow. While it was clearly identifiable with binoculars, a scope is needed for a good photo. Although the falcon was seen yesterday (January 22) by Mike, my husband Darrin and I -- ready with camera and scope -- did not see it this morning. When we get a shot, I'll post it here, and update the latest date seen. If you happen to go by and get a look, let me know in the comments.

Updates: A day or so after I posted this, Mike let me know that he was passing the Village Plaza when he saw the Peregrine heading west along Michigan Avenue. He followed it all the way into Inkster, when it easily passed Mike's car, going an estimated 65 MPH! Apparently, it hunts rather far afield!

7 Apr: Still present.
6 Mar: Still there!
30 Jan: Seen again today at the Village Plaza.
13 Feb: Now more often hanging out on the Michigan Avenue side of the building (see comments).

Dearborn CBC, 2010

RRBO has been coordinating the Dearborn portion of the Detroit River Christmas Bird Count (CBC) since 1995. The count is held each year on New Year's Day.

After last year's exciting count featuring winter finches, this year's count was very dull, with the second-lowest number of individuals in 14 years. The low numbers of raptors, Mourning Doves, and House Sparrows, and absence of any blackbirds, compared to recent years was due to most of the productive Ford properties being planted in hay and harvested this year, leaving them in barren stubble with no or few birds.

The best of these fields are the ones that are directly adjacent to a tree line where birds can roost or go for cover, with the original field at on the south side of Hubbard at Southfield being the one that has traditionally had the most birds. Here is what the field looked like this summer, after the grain was harvested and the hay bailed. This is looking west towards the Ritz Carleton hotel:

Whatever waste grain may have been left behind had long been picked over, leaving nothing for birds to eat. There is a coyote living in a den in the small nearby woodlot that I've seen several times. Here it is on count day, in the lower right.

A few fields did have sunflowers in them, but they had also been picked clean. We had very large flocks of blackbirds this fall in the sunflower fields. Here is a brief video I took in October:

A few fields were planted in a wildflower mix. Although some of the choicest plants, such as the bluestem grasses, had been de-seeded, there was still a lot of good seed left. We had most of our small birds in these fields.

The Ford Rouge Plant had not been harboring much waterfowl up to the count, since the Detroit River is still open. Among the usual suspects there was a new species for the Dearborn portion of the count: Bonaparte's Gull. This was also our first January record for this species. A few do winter in the Great Lakes, but most are found in the Gulf states or southern Mississippi River in winter.

On campus, several Golden-crowned Kinglets, and Fox and Swamp Sparrows were good finds. Elsewhere, in an undisclosed location, a Northern Saw-whet Owl was located. They are not too uncommon here in winter, just hard to find.

Afterwards, most local counters gathered on campus to exchange intelligence, warm up with a cup of coffee, and have some pizza. Below, clockwise from lower left, are Greg Norwood (territory = campus and Rouge River channel), Tom Carpenter (Rouge Park), Gary Hutman (Rouge Park), Rick Crossland (rover), me, and Jim Fowler (Ford Rouge Plant, Detroit River, compiler). Other participants missing from the photo are listed on the results page.

The majority of participants on the Dearborn count are Dearborn residents, and my own Dearborn neighborhood is well represented. Here are the Springwells Park birders: Cathy Carroll, Gary Hutman, my husband Darrin O'Brien, and yours truly.

For a complete list of the bird species seen and other stats, as well as the results of all previous years, head on over to the Christmas Bird Count page on the RRBO web site.

Rockwood CBC: Lots of Refuge properties

Dawn at Humbug, looking from Jefferson Avenue toward the Trenton Channel Power Plant.

Since 2004, RRBO has been participating in the Rockwood Christmas Bird Count (CBC) by surveying the Humbug unit of the Detroit River International Wildlife Refuge (DRIWR). Last year I gave a little background on this count and our coverage of Humbug. This year, my husband and I once again counted at Humbug, but we also made whirlwind stops at five other units of the DRIWR that are within the Rockwood count circle. Several are fairly new units that are under restoration and the USFWS wanted to see if waterfowl were using them. Since the units are not open to the public and we have a special use permit for various projects, we offered to give them a look. Although it rained on Christmas Day, the next day most standing water had refrozen, limiting waterfowl use. That was probably not a bad thing. If the water had been open, we'd still be counting. As it was, this was more of a reconnaissance mission. Now we know the logistics, and can make recommendations on how the units should be covered in the future. We ended up walking over ten miles, but only tallied 44 species, owing to our quick work at most of the units and drive time between them. It was nice to see a total of 10 Bald Eagles at 4 of the 6 units. A Killdeer at the Humbug unit was probably our best bird. Great Blue Herons are always found in good numbers at Humbug, since there is always some open shallow water there due to discharge from the Trenton power plant just north of the property. We had 49 herons at Humbug, close to our record of 53 in 2004. We had another 19 roosting around the old quarry pond at the Gibraltar Bay unit on Grosse Ile (more on the units below). Sparrows in general seemed sparse, although we had two Fox Sparrows at the Brancheau unit. All of our 148 American Robins were at Humbug, feeding on Common Buckthorn, honeysuckle, and perhaps some rose hips. We completely missed any blackbirds, Carolina Wren, Cedar Waxwing (also missed by all other teams on the American portion of the count), and, sadly, American Crow. Very few crows were found on the count; this species does not seem to be recovering from West Nile Virus. Here is a run-down of the units. 

• The Humbug Marsh unit is in Gibraltar and Trenton. At least half of the northernmost section was rehabilitated over the summer, and was either unvegetated or iced over, making that part quick work. I've attached a number of photos to this route, so hover over the map, and click on the first icon on the right to go into slideshow mode. We had 29 species here.
• The Gibraltar Wetlands unit is very near Humbug, behind the high school at Jefferson and Woodruff Road in Gibraltar. Since it was frozen and we only had a few birds there, I did not include this in EveryTrail.
• The Gibraltar Bay unit is the former Grosse Ile Nature Area (and a one-time Nike missile site) at the south end of Grosse Ile. We mostly went for waterfowl. 22 species.
• The Fix unit was the furthest south we traveled, and is adjacent to the Fermi nuclear power plant in Monroe Co. These old farm fields have been planted with prairie and grassland vegetation, but were unvegetated this winter. We had 15 species here, including our only Winter Wren. More info here.
Walking a muddy dike at the Fix unit, with the cooling towers of the Fermi nuclear plant as a backdrop.

 
• The Brancheau unit is north of Fix, on the other side of Swan Creek. These fields will also be planted for wildlife. A pump system has been installed to bring in water from Lake Erie so the fields can be managed for waterfowl or shorebirds. 17 species.
• The Strong unit is just south of Pointe Mouille State Game Area. It also has old farm fields, and a large wetland bordered by dikes. The main dike is tall and grassy, with fields and woods on one side, and the wetland on the other. In many places Phragmites makes it hard to see into the wetland. We had our Fox Sparrows here, along with most of our American Tree Sparrows. We also had a Sharp-shinned Hawk, less common than Cooper's Hawks here in winter. 24 species.

The final dike walk of the day, this one at the Strong unit.

Realistically, covering all these units effectively takes more than one group of people. In the future, we will probably continue at Humbug and then concentrate on Gibraltar Wetlands and Gibraltar Bay.

House Sparrow madness

The annual Christmas Bird Count (CBC) season is nearly upon us. The count in which I have participated the longest is the Detroit River MI/ON CBC, because the city of Dearborn is within the count circle. In 1995, RRBO started coordinating the Dearborn portion of the count, so there is intensive coverage in the city, and I keep a separate tally of the numbers in Dearborn before they are added into the count totals.

The CBC issue of American Birds, published by National Audubon, contains summary information and various analyses of CBC data. One standard article is the summary of highest counts of individuals for the U.S. Last year, the Detroit River count had a highest number of House Sparrows -- 4537 -- of any of the 1673 counts held in the U.S.

A quick look at my numbers showed that 77% of those House Sparrows were counted in Dearborn, and 3255 of them (72%) were counted in the various sunflower/wildflower fields planted by Ford -- 2400 in a single field, as I noted in my blog post last year. The Detroit River count also had the highest number of House Sparrows in the 2006-2007 count (5168), of which 57% were from Dearborn.

Does this mean that Dearborn, or the metro Detroit area, has the highest concentration of House Sparrows in the country? Hardly. Over the years, I've given some thought to the accuracy of counts of very common species considered "trash" by most birders, particularly House Sparrows, European Starlings, and Rock Pigeons. Let's face it: most people participate in CBCs and other bird counts in order to see what "goodies" might be found, not to spend the time it takes to get accurate counts of House Sparrows. I usually see numbers of mundane species coming into compilations as ballparked figures, especially in urban areas where counting these species can be tedious.

There is great value in being meticulous about counting very common species of birds. For nearly 20 years, I've conducted a Winter Bird Population Survey. I'm sure glad I took the time to count American Crows the first ten years or so (and there were often hundreds), because since West Nile virus hit town, numbers plummeted and have not recovered.

Despite whether you care about or like House Sparrows or other common birds, take the time to get reliable numbers on the various counts you participate in. These citizen science projects are some of the best sources of long-term population data we have, and their integrity may be jeopardized by "garbage in, garbage out."

In 2003, I co-authored a paper published in Ontario Birds summarizing the first 25 years of the Detroit River CBC. You can download a PDF copy here.

Thanks to Diane Newbery for publishing this House Sparrow photo under a Creative Commons license.