Fall 2009: Weeks 9 and 10 in review

Things have picked up the last two weeks, although the bulk of the birds have been American Robins. We're up to 295 banded this fall. At this pace, we may break our record of 354. Since we are working on determining what they are eating, this is the first year that I welcome them all!

I banded two interesting robins this week. One only had one leg. It looked like an old injury: the foot was gone, along with half the tarsus (the lower part of the leg). The other half of the tarsus was still attached under the skin, but apparently not by a tendon, as it moved and rotated fairly freely. It was all well-healed, and the bird was a healthy-looking adult.

The other robin had orange, rather than white, facial markings (below, with a normal robin up top for comparison). This picture doesn't quite convey just how bold and orange this bird looked. Although I can't recall ever having banded one quite like this, it's not too unusual to get robins with this orange color in place of buff or white on some of the wing coverts.

As for warblers, we are down to the usual Yellow-rumped Warblers, the occasional Nashville Warbler, and some Orange-crowned Warblers. The duller Orange-crowns, like the one below, look a lot like Tennessee Warblers. Orange-crowned Warblers have longer tails, and yellow undertail coverts.

The bird below is a little brighter. The long-tailed look is quite evident here.

For comparison, a Tennessee Warbler banded earlier in the season, a very yellow individual. Slightly different angle, but note the shorter-tailed look.

I also recaptured a Blackpoll Warbler on 22 October which I had banded 10 days earlier. It was very fat to begin with, and positively rotund upon recapture (it weighed 20.2 grams). This represents a late fall departure date for Dearborn.

Other late dates include a Common Nighthawk in west Dearborn on 20 Oct; four Chimney Swifts over campus on 21 Oct; Northern Rough-winged Swallows near the Rouge River, also on 21 Oct; and a Green Heron on campus on 22 Oct.

We have a week or so to go for fall banding before we wrap things up for the season.

Fall 2009: Week #8 in review

The brown birds of fall have arrived. Here's our first Winter Wren of the season. This species has a very broad range across the Northern Hemisphere. In England, it known simply as the "Wren." In Germany, it is called "Zaunkoenig," which translates to "King of the Fence." An evocative and accurate description for these little balls of fiesty attitude! We often seem to catch them early in the morning. Extracting from a mist net what amounts to an energetic and slippery ping-pong ball in dawn's dim light is one of banding's challenges.

Another brown bird of fall is the last of the Catharus thrushes to migrate through, the Hermit Thrush. This is my favorite of the thrushes in my study, although I like them all. They can be very common this time of year, although so far they have not reached a peak here by any means.

Our #1 species right now is the American Robin. Early October is the peak of migration for them, and the time when large numbers in wandering flocks are descending on campus. Because migration has been relatively slow this fall, I've been coming in on my days off whenever the weather is okay. The first net run or two in the morning can be loaded with robins. I had to drag my good friend Jim "The Big Bwana" Fowler out of banding retirement earlier this week to help out in case I got swamped with robins.


Dana Wloch is the UM-D student in charge of identifying and compiling all the seeds found in the droppings of robins and species other than Catharus thrushes, so she's pretty happy with all the robins right now.

The other group of brown birds that are abundant this time of year are the sparrows, especially White-throated Sparrows. They have certainly arrived, but not yet in the numbers I expect. The non-brown sparrow that is conspiciously scarce so far is the Dark-eyed Junco. We've only seen a few so far this fall. That should change in the coming week.

Fall 2009: Week #7 in review

Things picked up this week, although overall the weather was quite uncooperative, with rain or wind cutting down our hours substantially. We began the week with a Detroit Audubon Society field trip, which occurs around this time every year. It's an informal morning of talking about RRBO's research, answering questions, discussing the species that we bring out to show the group after they've been banded and just before they are released. This year there was a nice variety of birds. The photos below were taken by Bill Rapai, of Grosse Pointe Audubon.

Orange-crowned Warbler

Gray-cheeked Thrush. Speaking of which, one was
recaptured twice this week that ended up gaining
a whopping 12.8 grams over 11 days -- that's a
gain of 40% of it's original mass! I have had other
over-achieving Gray-cheeked Thrushes over the years,
including one that gained 16 grams. I don't have an
answer why this particular species would pile on so
much fat at this relatively early stage in their
migration (they winter in northern South America). In
these situations, I usually recapture them more than
once over 10 days or so in which weather doesn't seem
to be a factor in delaying their departure. They are
often recaptured the first time quite fat, and just get
fatter every time I catch them.

I've been training a new bander this season, Guadalupe Cummins. She is an environmental science graduate student here at UM-D, and I'm trying to convince her to work on a project having to do with birds. She began extracting birds and banding them on her own this week.

"Probie" and a goldfinch.

Speaking of student projects, we have now collected over 100 samples of bird droppings from robins and catbirds to examine for seeds (and far fewer from thrushes). Robins are especially productive, although sometimes they don't wait until they are in a bag to provide a donation. I carry little glassine envelopes to collect any errant seedy blobs, so long as I can attribute them to an individual bird. This activity has been the source of a lot of amusement and a variety of suggested names and titles. I'll leave you with the winner.

Julie Craves, the Number One of Number Two.

Where's the jet stream?

In my last post, I blamed the poor fall migration on the position of the jet stream. Fall migration is best following the passage of a low pressure system/cold front, with winds from the north or northwest. Weather systems in North America generally travel from west to east across the continent, with their route guided by winds aloft -- the jet stream. Thus, a nice dip in the jet stream somewhere in the western Great Lakes is most likely to bring the right kind of conditions for birds to move into our area.

My friend Mike McDowell posted some graphics and a nice explanation on his blog last week. Go take a look! His four-panel image comes from WeatherImages.org, and is updated at least daily. The direct link to the current jet stream position image is here, and as I write this on Friday afternoon, it looks like this:

At long last, the jet stream is beginning to sag south. Although it isn't in the ideal position (such as the example Mike posted), it should help move birds along.

The California Regional Weather Service has a great web site that has all sorts of jet stream images and forecasts, including loops. Use the North America "latest available" link here for a detailed current map. This link goes to an animated loop of a five-day forecast.

These maps and forecasts should be used in conjunction with radar images. The Wisconsin Society for Ornithology has a tutorial on how to understand radar images and so does New Jersey Audubon.

Here are those handy links again:

• Current jet stream position and three-day forecast, all in one panel.
• Current jet stream, detailed image with isobars.
• Animated loop, five day forecast.
• Menu of many jet stream image options.
• Radar image tutorial (WSO) and NJA.
  

Fall 2009: Week # 6 in review

Another slow week has gone by. We finally broke 400 new birds banded this week, after 28 days of banding. This time of year, we can expect to band 400 birds in a week. Other folks in the western Great Lakes have also complained about this being a really lousy migration so far. The culprit: the jet stream has for the most part been stubbornly parked at a high latitude, through the middle of central Canada. It's been in this general position since mid-August, a highly unusual situation. Migration is strongly influenced by weather systems, and weather systems are influenced by the jet stream. Rather than going into this here, I'll put some links together in my next post.

We did have a few mildly interesting days. The predominant warbler has been the Blackpoll, followed by Magnolia (below) and Nashville.

This is the time of year when we get very large flocks of blackbirds, mostly Common Grackles and lesser numbers of Red-winged Blackbirds, along with some Brown-headed Cowbirds and (if we're lucky) Rusty Blackbirds. So far, it has only been grackles, and they seem to have arrived/gathered a little early this fall. They mass on the oak trees, ripping off acorns, and carpet the forest floor flipping through the leaf litter. Because of their weight, grackles don't "stick" in the banding nets very well, but it isn't unusual to catch a whole batch of them if they are moving through the net lanes. This is never very fun. They can (do!) pinch quite hard with their sharp bills. They also have very strong feet and it can be uncomfortable if they grab on and get a toenail stuck in your cuticle.

I happen to think that grackles are pretty handsome, but right now they are molting. The one below is a young bird, molting from its dull juvenile plumage into the more typical glossy garb. Judging from the color, this is probably a male. The wing feathers are also molting, or I'd be able to tell which gender by the length of the wing -- males are larger than females.

Speaking of toe nails, here's a robin with pale nails; they are usually dark-colored. We see a number of birds lacking pigment in their nails every season. Often it is Gray Catbirds and robins for some reason.As you'll see in my next post, the jet stream and weather systems are finally on the move. So long as we can avoid rain and wind, things should pick up next week.

Fall 2009: Week #5 in review

It was another quiet week. There was an influx of migrants on Sep 15, and some obvious large movements of American Robins and Blue Jays beginning on Sep 17. Some new species were recorded this week. Philadelphia Vireos have a very tight fall migration window right around September 15. We saw our first on Sep 12, and banded two on the 15th.

The 16th saw our first White-throated Sparrow of the season, and more were around on Sep 20. Sep 19 we had our first Gray-cheeked Thrush. Cape May Warblers seem to have had a good year. We banded two nice-looking hatching-year males, one of which is shown at the top of the post.
Two older birds were also recaptured this week. The first was a female Northern Cardinal first banded as an adult on April 13, 2003, making her at least 7 years old. We had recaptured her a number of times in 2003 and 2004, but this was the first recapture since then.

Next was a Gray Catbird that had been banded as an adult, in its second year, on May 17, 2005, making this bird at least five years old. We have captured it several times each year, often in breeding condition -- this was a male.
And here's my ID tip of the week (don't get your hopes up that I'll have one weekly!). The bird above is a Chestnut-sided Warbler. Like many (most that I see) individuals of this species in the fall, there isn't any chestnut on the sides. However, the color of the back and top of the head are very distinctive. To me, it's just like the color you get when you use a fluorescent yellow highlighter on newsprint. What do you think?

How do we know what thrushes are eating?

Last fall, I described the focus of my research: the autumn stopover ecology of migrant thrushes. My paper summarizing weight and fat changes in Hermit, Gray-cheeked (shown above), and Swainson's Thrushes was published earlier this year. This is the third year of building on those results by looking at the specific resources thrushes use here in the fall. Because most migrant birds, including those that typically eat insects, also incorporate fruit into their fall migratory diet, the thrushes make great surrogates for a whole suite of migrant species.

There are lots of fruiting trees, shrubs, and plants on campus. Our banding area, for instance, is located in an area with a high density of Gray Dogwood (Cornus racemosa, below), a native shrub with plentiful white berries.

However, like most urban areas, many of the dominant fruiting plants are from non-native species, such as the Glossy Buckthorn (Frangula alnus) shown below.

As I mentioned previously, some of the questions I seek to answer include which fruiting plants and shrubs commonly found in urban areas -- both native and introduced -- are most important to migratory birds? What is their relative availability? If highly invaded urban natural areas are to undergo restoration efforts, which introduced plants should be left to provide resources for migrant birds while native plants become established?

To find out what the thrushes are eating, we simply collect the droppings they leave in the bags we use to transport the birds from the nets to the banding station. Because fruit passes through birds so quickly (and it is thought that many birds, especially migrants, choose fruit that can be processed quickly and efficiently), we know that whatever they poop out has been eaten on-site. We collect each sample in a plastic bag, labeled with the bird's information.

Later, I sort through and identify all the seeds. I have assembled samples of nearly all the seeds found in fruits growing in the campus natural area (certainly all the common ones). I've also put together a reference book, made up of magnified photos of seeds of dozens of species; these photos are available at the excellent USDA PLANTS database web site. It's actually pretty straightforward. I've had very few seeds I have not been able to identify. I think a lot of them are just malformed seeds of common species. So far, I've collected over 200 seeds from 100 samples from 79 birds (some are from multiple samples from the same bird captured more than once).

In order to determine if resident birds are competing with migrants for the same fruits, or depleting certain fruiting species before migrants arrive, I've started collecting samples from all species of birds, concentrating on American Robins and Gray Catbirds. As we catch WAY more robins and catbirds than thrushes, we will end up with a lot of samples. A UM-D undergraduate and bander, Dana Wloch, will be assisting with the sorting, identification, and compiling of the seed samples as an independent research project this fall. Her time will go to waste, so to speak (sorry, I couldn't resist).

Interested in what I have discovered so far? I'll be presenting an overview of my research and some preliminary seed sampling results at presentations at several bird groups over the winter. The first two are November 2 for Macomb Audubon Society, and November 16 for Grosse Pointe Audubon Society. Check their web sites for locations and times. I'll announce January program dates in a couple months.

Fall 2009: Week #4 in review

I don't have much to say about this week. It was pretty boring. We've had some nice groups of warblers, usually consisting of a dozen species, right behind the EIC. Not many have materialized in the banding nets, however. I think this may be the slowest start to a fall season ever. I've updated the stats in the sidebar, and leave you with a photo of a pair of Black-throated Blue Warblers banded this week. We need some good weather fronts to get things moving, but nothing looks promising over the next 5 days or so.

Fall 2009: Week #3 in review

In contrast to last week, this week was gorgeous. A high pressure system remained stalled over the region, creating beautiful weather but a doldrum of sorts for migrants. Last weekend saw some movement, and early in the week, which meant we had our first observations of Cape May Warbler, Magnolia Warbler, Black-and-white Warbler, Chestnut-sided Warbler, and Blackburnian Warbler. We banded several other new arrivals, including Nashville Warbler, Tennessee Warbler, Ovenbird, and Wilson's Warbler. As the week progressed, things just petered out.

Ovenbirds are a personal favorite.

The air is filled with the (obnoxious, if you ask me) begging calls of young American Goldfinch, a species that is among our latest nesters. We've started catching families. The adults are just now beginning their fall molt, and their old feathers are extremely worn.

The white wing bars on this adult male goldfinch have worn nearly completely off. Dark pigments make feathers stronger, and the pale areas often wear away first.

I've also netted a lot of hummingbirds this year; one day this week I released eleven. I presume many are the same individuals, but between mulitple birds in the nets at the same time and plumage differences, I know there were at least seven different ones out there one day. Hummingbirds require special bands and permits, so I just release the birds when I catch them.

A molting adult male hummingbird ready to zip off. Only a few of the 40 I've caught so far have been adult males or this one!).

The most disappointing news of the week was finding out that the massive construction project next door at Henry Ford Community College will not be complete for at least another month. This loud, dusty project is directly adjacent to my site, and the bulldozers, piledrivers, and other big noisy machinery get going just after sunrise. I believe this is having a negative impact on my banding activities. The resident birds seem to be used to the commotion, but when the hubbub gets vigorous, the migrants seem to move away from it all. Although the very large underground retention basin, capped with a parking lot, is supposed to be complete by October 15, this is a three year project and will continue the next two summers. Arrgg!

The big dig next door. If this view isn't enough, for the next couple of months, you can have the excitement of following along on a web cam.

Fall 2009: Week #2 in review

This week was largely a washout. Even during dry periods, the generally damp weather has really encouraged the mosquitoes, which are worse this year than I can ever remember them being. Yuck!

The first boreal-nesting migrant was banded this week, a young female Canada Warbler on 25 August. A couple more Baltimore Orioles were in the nets, thus breaking our previous fall record of 14 banded; we now stand at 16. I've banded five Yellow-shafted Flickers so far, which is above-average. They are fairly heavy and so do not "stick" in the nets very well. But they seem to love digging around in the new wood chips, so I expect we may set a record for this species this year as well.

Young (hatching-year) female Canada Warblers can be pretty dull.

Most notable bird banded this week, in my opinion, was an adult Red-eyed Vireo netted on 25 August. It was a recapture, and had originally been banded, also as an adult, in August 2003. This means this bird is at least 7 years old. We've had returns of other Red-eyed Vireos before, but prior to this bird the longest period between recaptures was less than 5 years. You can take a look at RRBO's age records on this page. It lists a variety of species with at least two years between captures. According to the Bird Banding Lab's longevity records, the oldest Red-eyed Vireo is estimated at 10 years, 2 months old.

What makes this particularly remarkable is that Red-eyed Vireos winter in South America, making the minimum distance traveled between Dearborn and the northern coast of Colombia about 2200 miles one-way.


Range map for Red-eyed Vireo, from Cornell's All About Birds, a recommended resource.

This bird, then, has flown at least 36,000 miles on migratory flights!

Looks like the weather will be much improved next week. With reports of migrants in the region already trickling in, things should start to get interesting soon.

Fall 2009: Week #1 in review

RRBO's 18th fall banding season began on 17 August. First, I must show you the fabulous results of our big net lane chipping project. It's like banding in a park!

The weather wasn't bad this week, so I did get to band every day. A drenching downpour cut things short on Thursday, as did gusty winds today. Things started out rather slowly, with mostly resident birds being captured. Of the 18 species banded, only two do not nest on site: Veery (one banded on Aug 17) and American Redstart (one banded on Aug 18).

Two species stood out. The first was Warbling Vireo. My fall average is 6 birds a season. I've already banded 10; I have only topped 10 birds in three years, and my record is 20. We'll see how that shakes out. Among those I banded this week was this individual, which had a deformed bill. The maxilla was about 2 mm too short, and curved to the left. This type of deformity isn't terribly uncommon. When it's minor like this, it doesn't seem to handicap the bird too much. If it's severe and interferes with feeding or feather care, the bird doesn't survive long. The bird below was a hatching-year bird of average fat and weight for this species at this time of year. You can read more about my compilations of bill deformities in this previous post.

The other notable species was Baltimore Oriole. Orioles are also common here, but they are early migrants. Some autumns, I catch none at all. My fall average is less than 3 birds a season, and my record is 14. I've tied that record already, with over half of them being captured yesterday -- six were in one net!

Same as last year, I will post a running total of the fall banding season in the right sidebar.

Getting ready for fall banding

You may recall when I first started writing this blog a year ago, some of my first posts were on the work involved getting the net lanes ready for the banding season. These past couple of weeks, we've been doing some work that will hopefully make the annual prep less of a chore.

On 1 July, I had a team of volunteers out to lay down weed barrier in the net lanes, after my co-worker Rick Simek had so kindly killed the earliest growth of vegetation and most recently mowed what re-sprouted. These people made fast work of this job! It took less than half a day to cut, lay down, and anchor about a thousand feet of landscape cloth!

Andy Dettling, Darrin O'Brien, Sheri Smith, Linda Patterson,
and Jerry Mitchell after a job well done!

Here's what the project looked like as we worked (from front
to back, Linda, me bustling around, and Andy).

On 6 July came the task of spreading a layer of wood chips on the cloth. The cloth is slightly translucent, and without some cover, weeds could still grow underneath. This is a HUGE job, but the soonest we could get a large group of volunteers was early August. So, a handful of people also turned up to at least get a layer spread. The wood chips were generously donated and delivered by the City of Dearborn's Scott Racer, in a very large truck.

No messing with dump trucks. Most of the loads came directly from the big chipper.

The City of Dearborn has a gem in Scott Racer, who delivered at least 10
loads of wood chips. Thanks also to his boss Bruce Yinger.

Darrin O'Brien, Jerry Mitchell, Mike Lapko, Karen Gref, Linda Patterson,
and Mike O'Leary still smiling after hauling at least 10 yards of wood chips.

In late July and early August, two more groups of students spread still more chips. This resulted in a shallow layer over all of the landscape cloth. Finally, on 3 August, an energetic and enthusiastic group of Ford Motor Co. volunteers finished up the job.

Part of the Ford crew. These guys were amazing! In this photo Noori
Pandit, Bob Sawyer, Anatoli Dubovitskiy, Mario Iaquinta, Franco
Ragazzi and Joe Mantle. Photo by Steve Lake, who I appointed leader
because he and Noori showed up first!

This was an enormous undertaking, with about 170 hours of volunteer work contributed; I lost track of how many giant loads of chips were donated. All of this represents a donation of at least $3000 of time and materials. This is how the Rouge River Bird Observatory thrives, so to all who helped, my heartfelt appreciation!

In the next week, I'll be doing some pruning, checking and repairing the fencing that excludes the deer, and putting up the nets. Fall 2009 banding -- our 18th fall season -- begins on 17 August.

More European Goldfinches

Update: This paper has been published! It's open access so you can read online or download the PDF; click on title below -

Craves, J.A., and N.M. Anich. 2023. ­­­Status and distribution of an introduced population of European Goldfinches (Carduelis carduelis) in the western Great Lakes region of North America. Neobiota 81:129-155. doi: 10.3897/neobiota.81.97736

On the heels of my recent posting on a report of a family of European Goldfinches in Waukegan, Illinois comes another report with photo documentation of a juvenile "EUGO". This one is from a the Racine, Wisconsin suburb of Mt. Pleasant, about 25 miles north of Waukegan.

An adult was first seen at the observer's feeder in June, although neighbors had seen multiple EUGOs at their feeder (and I have many reports from the Racine area). On 9 and 22 July, a young bird showed up, at times with an adult, and these were among the photos obtained:

Juvenile European Goldfinch, Mt. Pleasant, WI.

Left, adult European Goldfinch. On the right, the juvenile European Goldfinch on the left side of the sock, and an American Goldfinch on the right side.

Here is a map of the southern end of Lake Michigan; the counties reporting the most European Goldfinches are outlined in red. McHenry County in northern Illinois is the suspected point of release of many of the birds.


Keep those reports coming.

Photos copyright J. Scheef. Used with permission.

European Goldfinch update

Update: This paper has been published! It's open access so you can read online or download the PDF; click on title below -

Craves, J.A., and N.M. Anich. 2023. ­­­Status and distribution of an introduced population of European Goldfinches (Carduelis carduelis) in the western Great Lakes region of North America. Neobiota 81:129-155. doi: 10.3897/neobiota.81.97736

Earlier this year, I posted about a paper I wrote summarizing sightings of European Goldfinches (Carduelis carduelis) in the Midwest. A population is apparently established in northeastern Illinois and southeastern Wisconsin.

I just received a report from a resident of Waukegan, IL, about 10 miles from the Wisconsin border. She hosted four adult European Goldfinches last year, and up to eight this spring. On 20 June, she reported an adult with two youngsters in her yard. On 22 June, she saw four young with two adults, and sent these photos.

I've had a handful of reports of nesting European Goldfinches from Illinois or Wisconsin since 2003, but only two with photo documentation. This Waukegan report is the most detailed and the first definitive report away from the "epicenter" of sightings in McHenry Co., IL, which is about 40 miles west of Waukegan.

As they do in their native range, European Goldfinch nest in May and June, which is earlier than American Goldfinch. However, in Europe and Asia, they raise two broods, sometimes three, so nesting in the two species here in North America could overlap.


As you can see, the juveniles are superficially like dull or female American Goldfinch, but any good look will reveal the jet black wings with large yellow wing patches. Young European Goldfinch lack the red on the face and the head pattern of the adults. The Waukegan host will be watching to see when the young birds acquire the red faces of adults, (should they continue to come to her feeders) which I expect to happen sometime in the fall.

I welcome further reports of nesting European Goldfinches!

See also this update from July 2009.

Photos copyright E. Powell. Used with permission.

Spring 2009 Survey Season Summary

The spring 2009 survey season took place from 9 April through 9 June. There were surveys on each morning for the first 57 days, and two of the last four days. On campus, 140 species were recorded (another 17 were recorded in Dearborn off-campus). This is nearly 6% greater than the previous five-year average of 133 species. The peak calendar week was 17 through 23 May with 95 species, and the peak day was 18 May with 86 species.

Weather
In contrast to some recent spring seasons, spring 2009 seemed fairly "normal." The National Weather Service noted (PDF) that in Detroit, average tempertures for March through May were just a degree above normal, while rainfall was nearly 3.5 inches above normal. Most of the precipitation was in April; May was slightly below normal. Most noticable to me was the steady progression of vegetation leaf-out and blooming that was not interrupted by extreme cold (as in 2007) or abbreviated by extreme heat. Insect emergence and growth seemed normal. Although anecdotal, it appeared to me that food resources for migrants were adequate to abundant.

Arrival dates
While I track arrival dates for all migrant species, I especially focus on 43 regularly-occurring and conspicuous migrants. Of those, three species arrived earlier than had been previously recorded for Dearborn: Ruby-throated Hummingbird on 1 May (previous date, 1 May), American Redstart on 30 April (previously 1 May), and Indigo Bunting on 28 April (previously 29 April). Two species tied their record early arrival date: Tennessee Warbler on 29 April, and Black-throated Blue Warbler on 30 April.

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 16 years of spring arrival dates for nearly all of these 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 the 43 species:

• Four (9%) arrived on their average arrival date.
• Seven (16%) arrived later than average (the average for those species only was 2.4 days later)
• Thirty-two (74%) arrived earlier than their average arrival date (for those species, the average was 5 days earlier).
• For all 43 species, arrival time averaged 3.3 days earlier than "usual."
  

Most instructive would be an analysis of any shift in peak arrival periods, or the dates in which different percentiles of each species peak (e.g., the date each year in which the first 20% of Ovenbirds of the season have been recorded). I am in the process of computerizing all of our spring survey data back to 1994. Soon, I will have completed the input of 10 years of data, and will begin some preliminary analyses.

Highlights
There were a number of species represented by only one to a few sightings. Often this is due to a lack of habitat on campus so that visits or flyovers are rare (Common Loon, American Bittern, Grasshopper Sparrow). A few are just rather cryptic and hard to see, hear, or identify (Philadelphia Vireo, Connecticut Warbler, Lincoln's Sparrow). Some species occur annually or nearly so, but are at the edge of their range in southern lower Michigan, and are often considered "good birds." This year, they were Hooded Warbler (3 birds) and Summer Tanager (3 birds). Prothonotary Warbler is a species that does occur in the region but only locally, and 2 different birds were recorded this season. Falling somewhere between lack-of-habitat and actually-rare was a single Grasshopper Sparrow recorded on 18 April.

Species that in past years have typically been more common but were only seen once or a few times this spring were Red-headed Woodpecker, Acadian Flycatcher, Golden-winged Warbler, and Rusty Blackbird. All of these species are also declining regionally, if not range-wide.

You can look over the summaries of each week here at Net Results for more highlights.

Missing on campus, and with only one report in the city this spring, was Orchard Oriole, normally seen every year. The most surprising miss this spring was Willow Flycatcher. This is a typically common species, but was not definitively recorded this year. It is likely they were actually present, as a number of non-singing Empidonax flycatchers were seen, but without hearing them they can't be distinguished from the similar Alder Flycatcher. Overalll, Empids in general seemed scarce. The three most common species (Least, Willow, and Alder) were down 43% from last year. Their numbers were roughly the same as the previous 5-year mean, but a longer look-back period would be most useful and these calculations have not been adjusted for effort.

The most numerous species by number of individuals counted was Brown-headed Cowbird, a species which has made monumental increases the last few years. Four or five years ago, we'd expect to count around 200 in a spring season. This jumped to over 300 the next couple of years, then over 1000 last year to 1671 this year. I suspect that overwinter survival in the city has something to do with this, as numbers have been increasing recently due to the presence of the sunflower fields around Dearborn.

Other numerous species were American Robin and Northern Cardinal, also with over 1000 tallied. Yellow-rumped Warbler came in fourth place at 946, while American Goldfinch rounded out the top five at nearly 900 counted.

In general, numbers seemed to be improved from the last couple of years, but peak numbers of warblers, for instance, were not impressive. Twenty-nine warbler species were recorded, but only 9 species had peak numbers over 10 individuals and all of those were 20 or fewer individuals except for Yellow-rumped Warbler, which had a high count of 129 on 30 April.

More interesting trends will no doubt be revealed once I get all the years of survey data computerized and dumped into a stats program. I'll also be able to produce some fairly detailed charts on peak migratory times for many species.

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

I'll be working on data input and some other projects, mostly in front of the computer, over the summer and will be posting periodic updates here. Then fall banding kicks off in mid-August!

Spring surveys: Week 9, final edition

The transition from migration season to breeding season is essentially complete. For the week ending today, 55 species were recorded on campus on 4 survey days. Nearly all were resident or locally breeding species.

True passage migrants were:

• Swainson's Thrush (8 June, a new late date for spring in Dearborn by one day)
• Magnolia Warbler (4 June)
  

And local breeders (although not on-site) were:

• Broad-winged Hawk (6 June)
• American Redstart (4 June)
• Common Yellowthroat (5 June)

With thick foliage concealing often-silent females, finding late migrants is often a matter of luck. Birding at this buggy time is enough of a challenge that many people quit going out late in May. I have June records for most northern migrants, and I'm sure they are probably more common than even these records indicate. I'll still go out and see what I can find a few times in the next week or so, but the formal spring survey period is over. In my next post, I'll be summarizing the whole season.

Spring surveys: Week 8

We're in the final stretch of spring migration. In fact, the week ending 3 June will be the last 7-day survey week of the season. The next 7-day period will be surveyed 4 or 5 days, but since things are winding down, I feel I need to sleep past 5 AM for the first time in a month!

This week, 74 species were recorded on campus. There are still northern/boreal-nesting birds trickling through. They included

• Olive-sided Flycatcher (2 June)
• Yellow-bellied Flycatcher (1 and 3 June)
• Swainson's Thrush (28 and 31 May on campus, but through the period at my house in east Dearborn)
• Magnolia Warbler (30 May)
• Canada Warbler (29 and 31 May).

Other species of interest that nest regionally, but not on-site, included

• Acadian Flycatcher (30 and 31 May)
• Veery (31 May)
• Chestnut-sided Warbler (28 May)
• American Redstart (30 and 31 May and 3 Jun)
• Ovenbird (28 and 29 May)
• Mourning Warbler (3 on 31 May, 2 on 1 June)
• Common Yellowthroat (31 May, 2 on 3 June)
• Hooded Warbler (28 May).

Of interest to me was the reappearance of Brown Creepers. I'd been seeing them regularly through the early part of migration at the north end of campus near the Rouge River. One in particular was singing up a storm. The last time I heard or saw one was 3 May. Then one showed up near the usual place on 28 May, and two were together there on 3 June. We've had nesting records before, so I am keeping my eyes peeled for a whole family.

Spring surveys: Week 7

This past week saw a reduction in the numbers and diversity of birds, with 80 species recorded on campus. Daily species totals ranged from 38 to 58, with an average of 51. Nearly every day had wind directions from the north or east, which are not conducive to good migratory flights. As might be expected this time of year, the trees are fully leafed out, more female migrants are present, and the combination of hard-to-see and not-singing made for a challenge.

Of the 18 warbler species recorded in the past week, the highlight was a female Connecticut Warbler on 26 May. Unfortunately, it was seen briefly and not relocated. The dominant
warblers are the mid- and late season varieties: American Redstart, Wilson's Warbler, Canada Warbler, Magnolia Warbler, and Blackpoll Warbler, although numbers are small.

The other "good bird" was the third spring 2009 record for Summer Tanager, this one a female on 23 May. It was also seen briefly before disappearing.

Kingbirds have finally been on the increase, but small Empidonax flycatchers are still scarce. Both species of cuckoos have been seen this week, with the first Yellow-billed Cuckoos arriving on 22 May. On 25 May, three were seen together -- and one was carrying a stick, perhaps preparing to build a nest.

There are still a handful of Swainson's Thrushes being found every day. Other lingering migrants include Black-throated Green Warbler (one heard today) and White-crowned Sparrow (an individual recorded nearly daily up through yesterday).

Spring surveys: Week 6

Seven days of surveys yielded 95 species on campus for the week ending 20 May. We tallied over 80 species on both 16 May (82) and 18 May (86, our season high so far). On 18 May, there were 23 species of warblers recorded, with the only regular expected species missing being Cape May.

New spring arrivals this week included Lincoln's Sparrow on 15 May; Black-billed Cuckoo, Blackpoll Warbler, and Mourning Warbler on 16 May; and Yellow-bellied Flycatcher and Olive-sided Flycatcher on 17 May. Also notable were American Woodcock and Golden-winged Warbler on 18 May.

The last couple of days clear nights with south winds swept most of the migrants away, and we await another wave. Flycatchers remain quite scarce. We've had very few Eastern Kingbirds, one Yellow-bellied Flycatcher, and only a couple of sightings of Alder/Willow Flycatchers. Least Flycatchers have been consistent, but we've not recorded more than three on any day. Also conspicuous in their rarity have been Yellow Warblers, which are typically very common. Five has been our top count. Black-throated Blue Warblers are usually less abundant, but have also been rare this spring so far.

Elsewhere in Dearborn...
The big stony vacant lot at the corner of the Southfield service drive and Rotunda has been Dearborn's shorebird "hot spot." On 14 May, a Dunlin and a Semipalmated Sandpiper showed up there. These were both 3rd city records. All week there were plovers (up to 10) as well as one to five Least Sandpipers. Another Dunlin showed up on 20 May for the fourth city record. Horned Larks have been regular, American Pipits have been seen several times, and on 15 May a Northern Mockingbird was seen running around catching bugs!

Among the lumps and rocks, small shorebirds can be tough to see. Several of us have been checking the lot daily. Sometimes visits 20 minutes apart can yield completely different results!

"Psst. I think someone is watching us." Two Semipalmated Plovers.

Dunlin

Other faunal news...
Truly odd was this Beaver photographed by Mike O'Leary at the Greenfield Village oxbow pond. We'll see how much tree trimming the Village allows!

Spring surveys: Week 5

Surveys were completed every day for the week ending 13 May. The week began rather dismally, but a total of 97 species were tallied on campus by week's end. There were some highlights:

• An Osprey snagging a fish from Fairlane Lake on 8 May.
• A Peregrine falcon flyover on 12 May.
• A Red-headed Woodpecker counted on the North American Migration Count on 9 May.
• Hooded Warbler, also found on that count.
• The second Summer Tanager of the season on 10 May.

Twenty-one warbler species were found during the week, although only Yellow-rumped Warblers and Nashville Warblers were counted in two-digit numbers. The day with the highest warbler diversity was on 12 May, with 16 species.

Mid-migration has been stalled. There were few new arrivals this week: Blackburnian Warbler on 8 May, Eastern Wood-Pewee on 9 May, Bay-breasted Warbler on 10 May, and Orange-crowed Warbler on 11 May.

Weather fronts favorable for migrant movement were just not happening this past week, but things look set to change for the next few days. We should see the rest of the expected migrants, as well as larger numbers.

Dearborn's North American Migration Count

The North American Migration Count takes place the second Saturday each May. It aims to take a "snapshot" of migration, and is compiled on a county basis. My husband Darrin is the coordinator for Wayne County, and we covered the city of Dearborn together on May 9.

The first half of the day was spent scouring the U of M-Dearborn campus -- my daily spring bird survey deluxe. Joining us was our good friend and RRBO supporter Jamie Jacob. A cold front was approaching, and while the first hour or so was okay, the winds quickly kicked up, making it difficult to hear or see birds. As I indicated in my last spring survey post, birding has been a bit slow lately. We ended up with just 76 species for the campus. Our highlights were a Hooded Warbler in the floodplain along the Rouge River, and a Red-headed Woodpecker in the swampy area near the river at the north end of campus. It was one of only 14 warbler species seen on campus. The first Eastern Wood-Pewee of the season was found. There was an obvious increase in the number of Baltimore Orioles and White-crowned Sparrows over the last few days.

Julie and Jamie, hitting the trails.

After campus, we checked out all the various sunflower/wildflower plantings around the city. The sunflowers are, of course, all spent and sagging. The wildflower fields have all been recently mowed, and several fields were not planted last year at all. Thus, they did not have ideal habitat. But we were hopeful for shorebirds at some of the fields with large puddles -- there have been Least Sandpipers in a couple recently. But we were skunked other than Killdeer and Spotted Sandpiper. The wetland area near the Ford Rouge Complex visitor center is really maturing, and we had a lot of Red-winged Blackbirds and Northern Rough-winged Swallows. After these locations and a few others, time was running out. Darrin wanted to hit Grosse Ile, and I still had to roam around our neighborhood (where I had 30 species).

The species total for Dearborn was 83. Here is our list:

Canada Goose 67
Wood Duck 3
Mallard 10
Pied-billed Grebe 1
Double-crested Cormorant 1
Great Blue Heron 7
Green Heron 1
Turkey Vulture 6
Cooper's Hawk 2
Broad-winged Hawk 1
Red-tailed Hawk 1
American Kestrel 1
Killdeer 13
Spotted Sandpiper 1
Ring-billed Gull 39
Herring Gull 2
Rock Pigeon 9
Mourning Dove 35
Chimney Swift 11
Ruby-throated Hummingbird 3
Belted Kingfisher 2
Red-headed Woodpecker 1
Red-bellied Woodpecker 11
Downy Woodpecker 12
Hairy Woodpecker 4
Northern Flicker 9
Eastern Wood-Pewee 1
Least Flycatcher 3
Eastern Phoebe 5
Great Crested Flycatcher 4
Blue-headed Vireo 2
Warbling Vireo 2
Red-eyed Vireo 4
Blue Jay 59
American Crow 2
Tree Swallow 1
Northern Rough-winged Swallow 25
Cliff Swallow 6
Barn Swallow 13
Black-capped Chickadee 10
Tufted Titmouse 3
White-breasted Nuthatch 5
House Wren 14
Ruby-crowned Kinglet 3
Blue-gray Gnatcatcher 10
Veery 2
Swainson's Thrush 1
Wood Thrush 3
American Robin 165
Gray Catbird 18
Euro. Starling 261
Cedar Waxwing 6
Tennessee Warbler 3
Nashville Warbler 21
Yellow Warbler 4
Chestnut-sided Warbler 2
Magnolia Warbler 2
Yellow-rumped Warbler 8
Black-throated Green Warbler 4
Blackburnian Warbler 2
Palm Warbler 4
Black-and-white Warbler 4
Ovenbird 4
Northern Waterthrush 1
Common Yellowthroat 1
Hooded Warbler 1
Scarlet Tanager 4
Chipping Sparrow 11
Savannah Sparrow 11
Song Sparrow 11
White-throated Sparrow 4
White-crowned Sparrow 78
Northern Cardinal 34
Rose-breasted Grosbeak 11
Indigo Bunting 8
Red-winged Blackbird 46
Common Grackle 27
Brown-headed Cowbird 59
Baltimore Oriole 33
House Finch 5
Pine Siskin 2
American Goldfinch 43
House Sparrow 94

Spring surveys: Week 4

This week, 92 species were recorded on campus. Most of the new arrivals and good numbers occurred early in the week. By week's end, diversity and abundance were petering out, with only 46 species and under 300 individuals being recorded today (versus 73 species and nearly 700 individuals on 2 May). So most of the early-season migrants have moved out, and the mid-season wave has not yet arrived.

Some notable species were a flyover Common Loon on 4 May and a Summer Tanager on 3 May. The Red-headed Woodpecker was last seen on 30 April, and the Prothonotary Warbler on 2 May.

Spring bird walks

The Environmental Interpretive Center is having four Saturday morning bird walks. Registration is required. I've posted the details here.

Spring surveys: Week 3

Surveys took place on 6 of the 7 days between 23 and 29 April, with 28 April being a washout. Ninety species were recorded for the week, with 76 species being recorded on 26 April. A highlight was two Prothonotary Warblers. One was seen on 26 April by the boathouse of Fair Lane Estate. Another, which seemed paler than the first, perhaps a female, showed up on Fairlane Lake on 29 April. This photo was taken that day by Don DeKraker, who also shot the lovely Red-headed Woodpecker below. This bird first appeared at the EIC feeders on 28 April, and is still hanging around. There have been fewer than a half-dozen records of Red-headed Woodpecker in the last ten years here.
A couple of other notable rarities were found this week. The best bird was a Grasshopper Sparrow found in the community organic garden at the north end of campus on 24 April. The day before, a Rusty Blackbird was in a puddle next to a parking lot.

As expected there were lots of new spring arrivals over the week. Notable were an Indigo Bunting on 28 April, a new early date by a day and a Tennessee Warbler on 29 April that tied the early spring date.

Spring surveys: Week 2

A total of 58 species were recorded on campus this week. The nice weather over the weekend produced some first-of-the-season species: Green Heron, Blue-gray Gnatcatcher, and Brown Thrasher. Two Blue-winged Teal were seen on Fairlane Lake, also on the weekend. Today, a Sandhill Crane flew over campus.

Cool and dreary weather returned on Monday, and migration has been nearly on hold. Ruby-crowned Kinglets are beginning to outnumber Golden-crowned Kinglets, and there are still some Pine Siskins around, but the numbers and variety of migrants has been sort of at a standstill. But it looks like things are about to change. Skies will clear tonight, but the wind won't turn to the south until tomorrow night. Beginning Friday, we should see a nice movement of migrants. The cool weather has slowed down leaf-out, so they will be easy to see in the coming days.

Spring surveys: Week 1

The first week of campus spring surveys has been completed. It's felt like early March out there, and the diversity and numbers of birds have reflected the weather.

A total of 51 species were recorded. The only FOS (first of season) bird recorded was Yellow-rumped Warbler, with 7 recorded on 14 April. Other highlights included four Ring-necked Ducks on Fairlane Lake on 13 April, a flyover Peregrine Falcon on 14 April, and a lingering Red-breasted Nuthatch all week.

There are a handful of Pine Siskins around, and most are hanging around the pine trees by the estate. I've seen them chasing each other around and engaging in courtship flight, so they may be nesting there.

Brown Creepers can be fairly common, if unobtrusive, spring migrants here, but two have been seen consistently for several weeks near the Rouge River on the north end of campus. We do have nesting records here, so perhaps these are also breeders.

There have been a few Hermit Thrushes and a couple of Winter Wrens, but now they are starting to sing, which is quite a treat. The warm weather is supposed to begin tomorrow, so I expect many more first arrivals in the coming days. I'll be out of town this weekend, but the surveys will be well-handled by Jim Fowler and Jerry Sadowski.

Good birding!

Daily bird surveys available

I started my daily spring bird surveys last week. I follow a standardized route, and I put my results into eBird, where you can view them by selecting View and Explore Data, Week Report (choose a date), Hotspots in Michigan. Note that there are multiple listings for the natural area here on campus, because other people also put their sightings into eBird. My survey route hotspot is UM--Dearborn--Rouge River Bird Observatory.

Nearly every day, I do extensions to my standard route. I also put these in eBird, but they are not public hotspots. Results are included in daily totals, and I report highlights on RRBO's Latest Sightings page.

Thrush paper published

My paper on the fall stopover ecology of thrushes has finally been published. In addition to all the time it takes to collect data, analyze it, and write a good paper, actually getting it out for all to see is one LONG process! I submitted the paper in April 2008. It went out for peer review, came back to me so that I could respond to questions and comments from the reviewers, and went back to the editors, who approved it in August 2008. Then came the process of checking page proofs for errors and scheduling publication. So at long last, it is in the current issue of the Wilson Journal of Ornithology.

Craves, J. A. 2009. A fifteen-year study of fall stopover patterns of Catharus thrushes at an inland, urban site. Wilson Journal of Ornithology 121:112-118.

You can see the publicly-available abstract and tables at BioOne. I wrote a brief summary of the work last fall here at Net Results.