Peregrine Falcons nesting in Dearborn

[Update: The jury is still out on the band number and identity. Barb Baldinger writes: "We clearly saw 6/M, but want a better look. It could be 66/M and we only saw the second 6, the space and first 6 in the way the numbers are repeated. If that is the case, he is one of ours, Iggy from UD Mercy, Detroit, hatched in 2011."]
 
Dearborn regularly hosts Peregrine Falcons, mostly in winter. The most "famous" of these was a Kentucky-born female named "Ember" who hung around in 2010. We knew her history based on the color and alpha-numeric codes on her leg bands.

This site probably has the best explanation on how to "read" Peregrine leg bands. If one is able to get a clear look at the bands and is in the 13-state, 2-province (ND, MN, WI, MI, SD, NE, IA, IL, IN, OH, KS, MO, KY, SE MB, and NW ON) midwest region, the Midwest Peregrine Society's database can be searched for more information.

A favorite location for falcons around here are the Parklane Towers on the north side of Hubbard east of the Southfield Freeway. The tall concrete buildings must look like cliffs, and there is ample hunting in the planted fields, urban areas, and the concrete channel of the Rouge River nearby. In 2013, a pair of Peregrines were present at the towers. At least one was banded, but the bands could not be read. They apparently raised at least one chick.

Last year, a pair returned, but left again in May. One returned in the summer, for a few days but left again.

Two Peregrines were seen over the winter of 2014-2015, and by April seemed to be tending a nest on the roof of one of the towers. Last month, a juvenile bird was seen by the southeast Michigan Peregrine monitors, and the bands of one of the adults was read: black-over-red, 6 over M-- or (b/r) 6/M in shorthand. However, this combo did not get a hit in the database. Grrr....

As a bander, I know that some bird bands have a "silent" leading zero (e.g., the physical band shows 932-12345, but all associated data is really assigned as 0932-12345). There IS a falcon in the database under (b/r) 06/M, a male hatched on 12 May 2012 in Vernon County, Wisconsin named "Drew." He was part of a brood from two unbanded Peregrines nesting at the the Dairyland Power Cooperative's Genoa generating station, on the Mississippi River just south of La Crosse (where my husband grew up). The company has had a nest site 375 feet up on a smokestack at the plant since 1997 as part of a Peregrine restoration program.

Hopefully, Chris or Barb (the monitors) or an occupant of one of the buildings will get a better look or photo of the bands and we can confirm the identity.

I went by last week and found this interesting scene.

An adult falcon was watching the window washers start down the opposite building.

Perhaps I should have stuck around to see how that turned out!

Grasshopper Sparrows nesting in Dearborn

[Update: As of late July, the sparrows are still present. The vegetation is high enough that it is not possible to tell if they are feeding young without going out into the field, so we are unlikely to confirm this. However, their presence on territory this long indicates they have likely nested. Here's a link to an article Oakwood posted about the sparrows.]

On 26 May, long-time RRBO volunteer and contributor Mike O'Leary found several singing Grasshopper Sparrows in the vacant lot at Rotunda and Southfield. This lot was once the site of some Ford Motor Company buildings, which were torn down around 2003. It is now managed by the Oakwood Physical Therapy & Wellness Center. Even after all these years, the footprint of the old buildings on the easterly portion of the property closest to the Southfield Freeway and service drive can be seen.

Up to four singing males continued at the site in June. Grasshopper Sparrows are considered a Species of Special Concern in Michigan, a status just below the legally-protected status of Threatened. In addition to a significant population decline statewide, surveys have shown that their numbers have decreased 4% annually in Michigan from 1996-2007. During the Michigan Breeding Bird Atlas period in 2002-2007, Grasshopper Sparrows were only confirmed nesting in one western township in Wayne County. While Grasshopper Sparrows probably nested in Dearborn at some point prior to 1900 or so, there have been only a handful of records of spring migrants since the 1970s, and just one summer record of one individual. These territorial birds represent the first likely nesting in the city in modern times.

Low grasses and taller forbs (mostly sweet clovers, Melilotus ssp., and fleabanes,
Erigeron ssp.,) in the area favored by the sparrows.

Not all grasslands or fallow land is equal to the various species of grassland birds. Grasshopper Sparrows have a strong preference for habitat that is mostly grasses and forbs (herbaceous weeds) which are not densely distributed, interspersed with bare ground (up to 20%), and few or no shrubs. The portion of the site that once had buildings on it have numerous patches of bare ground or sparse vegetation on the former building footprint, and most of the sparrows have been found there.

Patches of bare ground are required by Grasshopper Sparrows.

Because it is adjacent to the freeway, the insect-like song of the Grasshopper Sparrows are very difficult to hear! The field is also full of dozens of nesting Savannah Sparrows, Red-winged Blackbirds, and Killdeer, among other species. They make quite a ruckus, but we believe there are still likely up to four singing male Grasshopper Sparrows and, due to their duration at the site and the persistence of the location of at least one of the males closest to the parking lot, they are likely nesting. Because we do not want to risk stepping on the ground nests of any sparrows or disturbance to any birds, we've restricted our regular surveys to the edge of the property after I made one thorough walk-through. After I notified Oakwood of this special bird, they instantly stepped to the plate and made plans to postpone any mowing of the field until August, after any young should be fledged and independent.

We will be keeping an eye on the sparrows to see if we can catch them feeding young in the next few weeks. Many thanks to Oakwood for the stewardship of these special birds.

Winter Bird Population Survey 2014-2015

The 23rd year of RRBO's Winter Bird Population Survey has been completed. December started out pleasantly but the survey season ended with a snowy and bitterly cold February. Weather aside, it was a fairly average year. The 14 survey days over the late December to late February period was typical. Surveys totaled about 23 hours, which is 6 hours below the 29 hours that are average, but represent the shortage that took place on our Christmas Bird Count day.

The 34 species tallied was a little below the 22-year average of 38, but can be partially explained by some habitat changes and restrictions. Access to the Rouge River behind Fair Lane Estate was greatly restricted due to being fenced off for riverbank restoration; vegetation along this area also removed. The river was frozen much of the period, and no waterfowl were counted after January 1. No Belted Kingfishers were recorded; they have only been completely missed on a few other counts.

Heavy construction activity along Fair Lane Drive also impacted bird activity along eastern edge of survey area. This construction will be continuing through summer, and likely also have an effect on spring surveys.

Eleven species were found on all 14 survey days. In descending order of abundance they were: House Sparrow, House Finch, Northern Cardinal, Blue Jay, Black-capped Chickadee, Dark-eyed Junco, Downy Woodpecker, White-breasted Nuthatch, Tufted Titmouse, Red-bellied Woodpecker, and Hairy Woodpecker -- all feeder birds.

Despite the availability of feeders, most sparrows were recorded in numbers well below average. Only a single Song Sparrow was recorded, while the previous season total average is 13. One or two American Tree Sparrows were recorded several times, but the previous season total average is 34. White-throated Sparrows have been common winter residents here, especially over the past decade. A total of 25 were counted this year, with an average per survey of 1.7, the lowest numbers since 2002. The previous 22-year means were 80 per season and 6 per survey; these averages since 2003 were 157 and 9. Juncos were also counted in below average numbers, although not as drastic. I'm not sure exactly what might have contributed to the depressed numbers of ground-feeding seed eaters, except that a lot of understory vegetation has been removed and perhaps there is less cover.

Fruit-eating birds were largely absent. No Cedar Waxwings, Hermit Thrushes, or Yellow-rumped Warblers were recorded. Most days there were no American Robins present, the maximum number on a survey day was 3. This represents the second lowest number of American Robins in 23 years. Fruit-eating species were generally scarce on local winter bird counts this winter, so it's hard to tell what impact the removal of fruit-bearing non-native trees and shrubs that was undertaken by the university may have had on these numbers.

The highlight was probably the Pine Siskins that were present in small numbers through mid-January. They moved on from here (and other places locally) and had not moved back through on their way north by the time the survey period ended. This was the only one of the "irruptive" species present on campus this winter.

Dearborn adds another new species!

On 1 March 2015, Larry Urbanski found a Long-tailed Duck (Clangula hyemalis) in the Rouge River near the Ford Rouge Plant. There is a photo attached to his eBird checklist (sign in may be required for one or both links) and the bird appears to be a male.

Mike O'Leary and I attempted to locate the bird this morning, and found a Long-tailed Duck that appears to be a female, or at least doesn't look like the bird found yesterday. In the photo below, it's the bird on the left, next to a Red-breasted Merganser. I should be able to post some better photos later.

Long-tailed Duck is the 260th species on the Dearborn list.

Most of the Rouge River is still frozen solid. The areas in the Ford Rouge boat slip and adjacent waters stay open all year. Other waterfowl present included a couple hundred Common Mergansers, at least 24 Red-breasted Mergansers, Canvasbacks, a few Ruddy Ducks, Common Goldeneye, Redheads, and Greater Scaup. There were at least 20 Great Black-backed Gulls -- a species not recorded in Dearborn until 1987. Ten sort of miserable looking Great Blue Herons hugged the shoreline, as did 10 Black-crowned Night-herons. There is a small pond inside the plant next to the river that accepts warm-water discharge from one of the steel mill facilities, and a bunch of night-herons have wintered there for years.

Many thanks to Larry Urbanski for this great find.

Dearborn portion of Detroit River CBC, 2015

The Detroit River Michigan-Ontario Christmas Bird Count was held, as it is each year, on January 1. This was the 37th year for the count, which is centered at I-94 and Warren Ave, and the 21st year that RRBO has coordinated the field work in the city of Dearborn.

The skies were fair, but the temperatures were cold and windy. This was the first real cold snap of winter after a very mild fall and December. It was cold enough to freeze up a lot of water, but as count day was only a few days into the cold snap, it had not really been cold enough to push a lot of regional waterfowl into the always ice-free areas in our count circle. For example, this was onlly the second year that Canvasback were not counted; in fact, Common Merganser was the only diving duck recorded this year.

Unfortunately, our two counters on campus had unexpected family obligations, resulting in the best remaining habitat in the circle being under-covered. We had the lowest number of party-hours in our history, and raw numbers of many species of common birds were record lows, but not really reflective of actual populations. For these species, the Winter Bird Population Survey will provide more accurate numbers.

The obvious highlight of the count was a Lesser Black-backed Gull, found at the Ford Rouge Plant by Jim Fowler, Mike O'Leary, and Dave Washington, and photographed by Dave.

Most years this team is able to get special permission to enter the complex and check out the open water in the boat slip and other areas not visible from outside the plant. This is the third Dearborn record for Lesser Black-backed Gull. The others were also at the plant, in January and December 2004. This brings the cumulative total for the Dearborn portion of the count to 88 species.

Fifteen Black-crowned Night-Herons were also in their usual wintering spot around an awful little pond in the plant (described in the 2011 post). Most Black-crowned Night-Herons move south for the winter, but a few stick around coastal spots in the Great Lakes.

A view of the Rouge complex from the Dix Street bridge. Urban birding, anyone?

The usually-productive Ford "sunflower" fields mostly lacked birds this year. The only one with sunflowers was at Ford World Headquarters, where we did have 48 Red-winged Blackbirds and many House Sparrows and American Goldfinch. However, all the sunflower heads were seedless. The fields at Hubbard and Southfield, usually the best, had been planted in hay and harvested. Not even weed seeds were evident.

One field had a few rows of sunflowers at the edge, but they were stripped and had no birds.

As usual, we had a Peregrine Falcon at the Ford World headquarters and vicinity, and another one heading north up the Rouge River behind Henry Ford College. There have been two reported off and on this winter in the area.

A male Ring-necked Pheasant that we flushed at Porath Park was the first on the count in 11 years. Porath (Kielb) Park is an 11-acre property in a sparse residential area adjacent to railyards and an industrial border of Detroit was once a clay mine for bricks. In the 1940s, fill material from construction of I-94 was added. A federal brownfields grant was used to clean up contamination (still no digging allowed, according to warning signs) and it was turned into a park by the city in 2005. There are a variety of native plants there, but aside from a trail that is mowed through it (although not this year, apparently), the park has not been maintained very well and it's becoming weedy and overgrown. Still, we like to go take a look each year.

Everyone familiar with this count and our winter bird surveys knows that Dearborn has not seen its American Crow population recover since it was decimated by West Nile Virus -- my most recent summary is here. For this count, we've only counted 1-3 the last few years and this year it finally happened: no crows for the first time in the history of the count.

We ended the day with 38 pecies, which is a record low.
 

I've written summaries here at Net Results for the 2014, 2013, 2012, 2011, 2010, and 2009 counts.

Fall 2014 fruit and seed work

I mentioned in a previous post that our analyses of seeds found in the fecal samples of birds requires context: some sort of compilation and rank abundance of all the ripe fruit available to birds to eat when they are present in the area. In that post, I described our fruit counting methods.

Fruit morphology
Another aspect of our work this fall was describing various morphological characteristics of the common species of fruit available at our site. Many factors go into fruit choice by birds. Among them are the size of the fruit, how many seeds it contains, and the size of the seeds.

Some of these data are available in the literature. As I searched for these metrics, I found that for some species different sources reported quite different numbers, some sources had data on one characteristic but not others, while measurements for some species were not to be found. The best, though not the easiest, solution was to take measurements ourselves. Weekly, we collected around 10 fruits from each of around 30 species, measured the fresh fruit, counted the seeds per fruit, and measured the seeds. Dana Wloch started this project last year, and it was expanded this year. I'll be finishing up with some of the late fruiting species next week, but so far we have measured about 3300 fruits and over 7000 seeds!

Some of our results are basic. For example, the average diameter of the five most common seeds in fecal samples (Common Buckthorn, Amur Honeysuckle, American Pokeweed, Riverbank Grape, and crabapple) is 8.2 mm. This agrees with other studies that have shown bird-dispersed fruits typically average about 8 mm.

Some results are much more intriguing. Glossy Buckthorn is a non-native species that can be quite invasive, especially in wetlands. A recent study from its native range in Sweden stated the average diameter of the fruits was 8.7 mm (458 fruits) with an average of 1.7 seeds per fruit. We measured 134 fruits here over two years, and the average both years was 7.7 mm. The average number of seeds for 168 fruits was 2.5.

Glossy Buckthorn fruit does not ripen simultaneously, so red,
unripe fruit are often on the same branch as black, ripe fruit.

Glossy Buckthorn has been shown to have evolved different morphological characteristics in different parts of its native range. This species has been present in North America for over 200 years. If our data is truly representative of the local population, it might suggest adaptation to a different suite of dispersers, exposure to more or better pollinators, and the higher seed set may be a factor in its success as an invader. All speculative at this point, but no doubt it will prompt me to continue measuring Glossy Buckthorn!

Seed samples
Meanwhile, during the fall season, we collected 453 fecal samples from 6 bird species. However, over 80% of the samples were from robins that we did not band. Several years ago, the University began cleaning off all sidewalks and roads on a daily basis in fall. In a number of areas, low spots in the pavement hold water and attract robins, which often then "leave a deposit." Collecting these samples in communal bathing and drinking areas, as well as along other paths where we observed robins foraging on the ground, is a convenient way to acquire a lot of data.

For catbirds, the top four species in our 41 samples this fall were:

• American Pokeweed (native)
• Riverbank Grape (native)
• Amur Honeysuckle (non-native)
• shrub dogwoods (native)

This closely follows the rankings for the 5 previous years combined. Pokeweed and grape have ranked #1 and #2, while the shrub dogwoods have been #3 and Amur Honeysuckle and Glossy Buckthorn are close together at #4 and #5.

Sample sizes for robins are much higher. This fall the 453 samples revealed the top four species as:

• Amur Honeysuckle
• Common Buckthorn (non-native)
• crabapples (non-native)
• Riverbank Grape

These four species are also the same top four species from over 900 samples from previous years, although Common Buckthorn has been the top ranked species for those 5 years.

Two other species in robin samples were notable. Previously, Multiflora Rose (non-native) was found in 4% of samples; this year it increased to 6%. This is interesting considering a number of Multiflora Rose has been reduced in the past year or so both by removal and from infection by rose rosette disease. We also have the native Illinois or Climbing Rose (Rosa setigera) here. There is overlap in the appearance of seeds of these two species, but there are fewer R. setigera, their hips are larger and "ripen" later than multiflora. I believe most of the seeds found in fall samples are probably multiflora.

A comparison of the large hips of the native Rosa setigera (left) and the
small hips of non-native Rosa multiflora (right).

Asiatic Bittersweet (non-native) was previously found in less than one percent of samples. This year, it was in 5% of samples, a rather large jump. This species has also been the target of removal the last couple of years. The capsules encasing the fruit usually open fairly late in the season, and did not seem much earlier this year (first date in samples Oct 8) than the average (Oct 16). Thus, neither increase in the number of plants nor early fruiting seems to explain the higher proportion of samples with bittersweet.

Asiatic Bittersweet is especially conspicuous when there are no leaves on trees.

One possible explanation for the increase in these two species is that robins are eating more of them because a great deal of their top-ranked species (buckthorn and honeysuckle) have been removed in the larger landscape.  However, annual fluctuations due to weather and crop size can be large, so it will take more years of sampling to see if this year was just a quirk, or if trends will start to appear.

I haven't done much digging through the numbers yet, but even this quick look is pretty interesting. 

Fall banding 2014 (last season?)

We wrapped up the 2014 fall banding season on 30 October. This was a tad earlier than usual, but the last week was marred by deer destroying two more nets, and the sighting of yet another "stray" cat.

Is the RRBO banding program in jeopardy?
As noted in a previous post, this was a challenging season. Due to funding shortfalls, we cannot maintain the banding area as needed, and more importantly our hours have been cut. On banding days, all attention has to be devoted to tending the nets and the birds. We also had to spend time doing vegetation surveys when plants were fruiting throughout the season. As a result, time did not allow me to keep up with all my usual activities. Among things that went by the wayside were posting more regular updates to this blog and social media (I apologize!), and doing data analysis or writing the paper I am currently on, the results of our thrush diet study.

My obligation as a bander and researcher is to interpret and disseminate data we have already gathered; we need to make this a top priority. I have been tasked with raising at least $20,000 this year to maintain our current (reduced) schedule without further cuts. If we face more reductions in hours, we certainly will not be able to band next year. If we can top our goal, I hope we can resolve some of our time and resource issues and band at least part-time next fall.

Will there be nets in the net lanes next year?

The fall 2014 banding summary, part 1: the birds
On to the birds. RRBO banded on 17 days between 18 August and 30 October. We utilized only about two-thirds of the number of nets we usually do, arranging them to avoid the most deer-prone areas to minimize destruction of nets and harm to birds. We still lost some nets but the damage occurred when they were closed and no injuries to birds resulted.

We captured 317 birds of 46 species. Since we tried to band on days when we hoped to maximize our captures of target species (this year, catbirds and robins), our capture rate* was 50.6 birds per 100 net-hours, the highest since 2006. However, cherry-picking days for good conditions, versus banding every day, means that we can't really compare these results with previous years.

We did succeed with our modest goal, as catbirds and robins were the top two species banded. In fact, despite the very limited schedule, our 38 new catbirds banded was a higher total than the past two years, which were dismal record lows. And we got over 40 seed samples from catbirds (more on that in the next post).

The highlight of the season was the Marsh Wren banded on October 9 described and shown in the previous post. A Blue-gray Gnatcatcher on September 15 and a Yellow-bellied Sapsucker on September 29 were other less-common species in the nets. While it's hard to judge without daily banding or surveys, all thrushes, but especially Hermit Thrushes, seemed scarce this fall, as were sparrows such as Lincoln's, Swamp, and even White-throats.

Although on my own time, I thought I would mention that I also banded at a Washtenaw County site previously used for the catbird project. Although using fewer nets than RRBO in 12 sessions for about half the number of hours, the capture rate was higher at 59.6 birds per 100 net-hours, a great result given that we did not choose our banding days based on conditions. We captured 167 birds of 27 species, with American Goldfinch and White-throated Sparrow being the top species. I am experimenting with this site for several reasons: to test the potential as a back-up for RRBO's campus site, to collect fecal samples to determine diet at a site less-invaded by non-native species to compare with RRBO's data, and to train an enthusiastic future scientist, Aspen Ellis.

Aspen is a UM-Ann Arbor student who has already accumulated a lot of varied ornithological experience: for many years she has prepared bird specimens at the University of Michigan's Museum of Zoology, and she has worked on Audubon's long-running Project Puffin as a research assistant the past two summers in the Gulf of Maine. Aspen's dedication to birds and science has been recognized by the Tim Schantz Memorial Foundation with a scholarship to Alaska to present her puffin experience, and the American Birding Association in their Young Birder of the Year contest. Read about her experiences and goals in her own words here at the eBird website.

Banding in Dearborn wasn't very practical for Aspen around her school schedule (and that of the family's cars!). But her clear commitment to bird conservation and science and her maturity spoke to me, and using the Washtenaw County site -- very near her home -- was the answer. It was a pleasure working with her. She is a fast learner and was mastering the basics as the season drew to an end; I hope we can continue the process next year.

Aspen and a female Eastern Towhee.

Part 2: the fruit data
The paper I am working on now is looking at seeds from fruits in the diets of over 300 Hermit and Swainson's Thrushes. I began with them because my previously published paper documented weight gains in these species. Meanwhile, we are still collecting data on other bird species. We have good samples sizes from catbirds (over 200), and a great data set for robins (well over 1000 from the fall seasons alone). Since catbirds and robins nest here, we would like to see if the fruit in their diets differs from the thrushes, which are only here during migration. Since we also have data for robins from summer and winter, we can also look at how their diets change throughout the year. We have also collected over 1000 specimens at the Washtenaw County site for comparison.

I will summarize a very demanding and interesting season of data on fruit availability and diet sampling in my next post.

A huge thank you to two people. First, Dana Wloch returned for yet another year of banding and seed processing. This year, measuring fruits and their seeds was added to her repertoire. In past years, she has been supported by grant money. This year, she came in several days a week as a volunteer. Truly, I would have gone insane without her.  At the Washtenaw site, my husband Darrin O'Brien forfeited his Sundays to help out banding and training Aspen. Darrin is a talented bander...and every new bander should get more than one perspective!

---

*In order to compare different locations or years that may operate the same number of hours but with more or fewer nets, capture rate is calculated by "net-hours." One net hour is one 12-meter net open one hour, or two 6-meter nets open one hour, etc. This rate is often expressed per 100 net-hours for more manageable numbers.
 

Field work, fall 2014

We have been dividing our time here at RRBO censusing and measuring fruit, and banding birds in order to collect the seeds of fruit eaten by the birds.

I know you want me to show you bird stuff first!

Bird of the season so far goes to this Marsh Wren, only the second ever banded by RRBO; the other one was in 1999. Since there are essentially no marshes in Dearborn, this is not a common species here, and this is only the 7th record. Probably the coolest thing was the amazing sound this bird made. 

 

One of the most interesting warblers I've banded lately was this adult female Black-throated Blue Warbler. In dimorphic species, sometimes older females can have relatively male-like plumage. This gal had a lot of blue tones in her feathers, a darkish face, and a very large white "hanky."

Orange-crowned Warblers are always nice -- one of the treats of late fall.

We catch very few Yellow-bellied Sapsuckers -- this is the 6th in over 20 years -- so this youngster was fun to see. Woodpeckers tend to hammer on your fingers, and the very fine, chisel point of a sapsucker bill is an effective weapon...

 

...although nowhere near as formidable as the powerful bill of a Rose-breasted Grosbeak. We always give grosbeaks a lot of respect!

One thing we always look at when trying to determine the age of birds is whether there is contrast between old and new feathers. In the photo above, it's easy to see the four paler, more worn wing feathers, which she has not replaced this year, and how they contrast with the new, fresher, darker wing feathers. The new feather in the middle that is a bit shorter is still growing in.

Onto the fruit. Our analyses of seeds found in the fecal samples of birds requires context: some sort of compilation and rank abundance of all the ripe fruit available to birds to eat when they are present in the area. Each year, we estimate the percent of ripe fruit on the common species once a week or so throughout the season. This year we are making sure we have complete data on all fleshy fruits available, even if they have not shown up in fecal samples -- all together around two dozen species. For less-common fruits, we have tried to locate and count all individual fruit, once a week. For abundant species, we cut down branches, counted all the fruit, and came up with an average for a "representative" branch. Then we go out and count the number of representative branches each week in a 200 meter circle centered on our banding area.

I can tell you that this work falls under both "tedious" and "easier said than done." It is not precision work (and it varies annually depending on fruit crop), so what we'll end up with is a list in approximate rank abundance, based in categories that increase by orders of magnitude. Even with that crude ranking, it's not easy and very time consuming. Much of our counting is done along a busy public bike path. People are intrigued when they see one of us standing and staring at the vegetation for long periods of time; they inevitably ask us what I am looking at. I know I have become much more adept at writing down my fruit counts and keeping track of where I am so that I can stop and explain what I'm doing.

How many ripe multiflora rose hips are just
in this one bush?

We also take various measurements of the fruits of each species throughout the season: the diameter of individual fruits, how many seeds they contain, and the diameter of the seeds. This can help us understand what size fruits are favored by different bird species, if they prefer fruits with a few large seeds or more small seeds, etc. Some fruits are simple: the shrub dogwoods are typically 5 to 8 mm, and have one seed. Then there are fruits like Climbing Nightshade (Solanum dulcamara), which have around three dozen, 2 mm seeds each! All get dutifully counted and measured. 

We start on Monday, spend at least one full day just working on fruit, and finish as best we can on days we band. Due to our funding shortfall, our days have been cut back so we are cramming as much work in as possible.

These tasks would not be possible without the help of Dana Wloch, who first started with RRBO as an undergrad, then under several grants, including one where she helped develop our seed identification website, and now is back as a volunteer. Thank you, Dana! We are the dynamic fruit duo of Dearborn.

RRBO update

It's been awhile since I've posted an update due to some changes here at RRBO.

As has been the case with many non-profits, fundraising has been particularly challenging over the past five years or so since the recession. While things have improved recently, RRBO's funding shortfall has forced us to reduce our operations. We're doing our best to try to prioritize research activities on our curtailed schedule. One goal is to finish a solid version of a major paper on the diet of Hermit and Swainson's Thrushes on fall migration. Most of the analyses and a big chunk of the writing is done, and this fall we are working on the last of our fruit crop surveys and fruit/seed morphology work (more on that in another post) which is both time-sensitive and time-consuming! Our fall banding has been focused on catbirds and robins, as these can be the subject of another paper.

Two things have further limited our banding program this fall. After 7 years, the plastic deer fencing that we found necessary to install around the banding site has finally deteriorated so that we are no longer able to repair it. Given the current circumstances, we don't have the resources to replace it. The deer herd has grown substantially since the fence was put up, and due to major construction on the other end of campus, many deer are in and around the banding site. We're using fewer nets and reconfigured them to (hopefully) minimize potential damage, conserve our equipment, and provide a safer situation for birds.

Second, in early August we discovered that someone had dumped 10 or more cats around the Environmental Interpretive Center, and had also been feeding them. This is a tragedy for both the cats and the wildlife. We cannot band birds when there are free-roaming cats in the area, and it takes considerable effort for us to trap these cats, if we can at all.

Therefore, we are doing limited banding here on campus as well as at the Washtenaw County site we used last year for the catbird study. Speaking of which, while we did see a number of catbirds banded in previous years this spring and summer, we only saw one returning bird with a geolocator, and many attempts to recapture it were unsuccessful. Many of our catbirds return multiple years, and the batteries last on the geolocators for two years (and even if dead, the data can still be accessed). We may still get one this fall; otherwise we will have to see what happens next year.

Spring bird survey results

Over the months of April and May, 127 bird species were recorded on campus, bringing the 2014 total to 139 species. For the city of  Dearborn, the 2014 species count is 141. The best day was 8 May with 73 species reported, including 19 warbler species. The previous 5-year average for April-May counts on campus is 131, so this year was only slightly below average. Big misses (excluding several species mentioned in the warbler account below) included Black-billed Cuckoo and Willow Flycatcher. Flycatchers in general have seemed scarcer here in recent years, although this year we had good numbers of Least and Yellow-bellied Flycatchers.

The entire survey season was severely hampered by major construction on campus directly adjacent to the Natural Area. In particular, there was daily jackhammering in the parking structure, which served as a giant amplifier and made hearing anything in the northern half of the area nearly impossible. Fortunately, the prolonged cold of early spring delayed leaf-out, so many birds were easy to see.

It was a good year for warblers. Despite missing Golden-winged Warbler, Orange-crowned Warbler, and Hooded Warbler (which although rare is still recorded almost every year), we recorded 28 species. Highlights included:
Prothonotary Warbler -- A silent individual along Fairlane Lake on 9 May.
Connecticut Warbler -- Singing male 27 May.
Prairie Warbler -- One reported on 10 May.
Yellow-breasted Chat -- One along the south bike path was the first Dearborn record in 8 years.

Other highlights included:
Osprey -- Individuals seen around Fairlane Lake on 18 April and 14 May.
Bald Eagle -- Flyovers on 15 and 17 April were the third and fourth records for campus for the year.
Olive-sided Flycatcher -- One on 28 May by the Fair Lane Estate boathouse.
Acadian Flycatcher -- Singing along Fairlane Drive on 21 May.
Eastern Bluebird -- A male by the EIC on 14 May. 
Summer Tanager -- A male near the EIC on 24 May.
Bobolink -- A male singing high in a tree in the forest adjacent to Fairlane Lake on 28 April tied an early spring date for Dearborn, and was radically out-of-habitat!

An interesting Baltimore Oriole first found by Dr. Orin Gelderloos and his field biology class on May 21 and present through at least the end of the month near the north bridge over the Rouge River, behind Henry Ford College. It had the typical plumage of an older male, except it had no black on the head or face, and just a smattering down the chin and chest. The head color was a glowing golden orange, and the bill color was horn/beige, rather than the usual blue-black. Thus, it apparently had some sort of lack of melanin in the head -- quite stunning and unique!

RRBO's work on Detroit Public Television

Detroit Public Television and The Nature Conservancy have partnered to produce a series of programs on topics of regional environmental importance called Great Lakes Now Connect. Coming up next week is their program on migratory birds, and Julie Craves and the work of the Rouge River Bird Observatory are among the featured scientists.  Here is a terrific preview:


Or you can view it here.

Please note that in this preview, and I assume in the program as well, I have received an "educational upgrade." I don't want to misrepresent myself: I do not have a doctorate, a fact that unfortunately didn't make it to the final editors of the show. This lack has presented a major challenge over the years, as I do not have the access to funding that is more readily available to faculty members or other more highly-credentialed researchers. Yet without the benefit of more traditional academic support, RRBO has made scientific contributions meaningful enough that our work can be included with that of amazing people like Michigan's own Dr. Dave Ewert and Dr. Jen Owen. That's due in very large part to RRBO's faithful and generous donors, making RRBO a truly community-based conservation organization.

Please enjoy the preview, and watch the program -- it will live-stream on GreatLakesNow.org on Tuesday, May 6th from 1 to 2 PM. EST.

Winter Bird Population Survey 2013-2014

The 22nd year of RRBO's Winter Bird Population Survey has been completed. Those of you that know me know that I do not like winter. I can't believe I've been doing this for so many years, and the weather this year made it especially difficult, mentally and logistically! This will wind up being the second snowiest winter on record for the Detroit area. There was snow cover the entire late-December to late-February survey period, and walking was often difficult. Worse were the cold temperatures. Despite many days of sub-zero temps or wind chills that at times prevented me from going out, I still got in 15 surveys (the average is 14). On the "bright" side, water was frozen most of the time, and I was able to do the around-the-lake portion of my route on the lake, which was easier to walk on!

This year 42 species were tallied. The previous annual average number of species is 38. Two new species were added this year: Purple Finch and Red-breasted Merganser, bringing the cumulative species total for 22 years to 75. The Purple Finch was seen twice. This is a species that is a fairly common migrant here, but not very frequent in winter and never recorded on a survey day. Thus, it was perhaps and "expected" species.

Much less expected were the Red-breasted Mergansers, which usually overwinter on big water (oceans, large lakes, or in smaller numbers on large rivers). Several were seen with Common Mergansers (and some Common Goldeneyes) in the Rouge River where the lower Rouge enters the main river at the south end of campus. This occurred on the last survey date, after a very long period of cold weather, on the only open water in the vicinity. This was only the second record of Red-breasted Merganser on campus and one of the few Dearborn records outside spring migration. Here is my lousy cell phone photo of an adult male:

The ice cover was responsible for the low numbers of our most common waterfowl over the course of the survey period. Canada Goose and Mallard were each only recorded on one day. Great Blue Herons and Belted Kingfisher were also mostly absent this year.

Last year, Merlin was a new species, and we had another this year, on 10 February.  The falcon was sitting along the river near the waterfall behind Fair Lane Estate, and was spied by an American Crow, the only crow recorded during the survey period. The fiesty Merlin turned the tables on the crow and chased it off. A fun, yet bittersweet, encounter, given the continuing lack of recovery of crow numbers here in Dearborn. This marks the tenth time in the past 12 years when fewer than 10 crows were counted on the survey.

On the other hand, people commented that Blue Jays seemed quite abundant this year, which was confirmed on the survey. Our average is 122 a year, and we had 216 this winter, a record.

After last year's winter finch invasion, we had no Pine Siskins, Common Redpolls, or other species usually included in this group (including Red-breasted Nuthatch). But due to deep snow we did have a lot of seed-eating birds hanging around our organic garden, native gardens, and bird feeding areas. Mourning Doves, White-throated Sparrows, Dark-eyed Juncos, House Finches, and House Sparrows were all counted in above-average numbers.

Dearborn portion of Detroit River CBC, 2014

The Detroit River Michigan-Ontario Christmas Bird Count was held, as it is each year, on January 1. This was the 36th year for the count, which is centered at I-94 and Warren Ave, and the 20th year that RRBO has coordinated the field work in the city of Dearborn.

The weather was probably one of the most miserable we have experienced on a count day. Temperatures did not exceed 11F all day, it was windy, and it snowed continuously. As it had been snowing much of the previous night, roads were slippery and a hazard. While waiting at an intersection at one point, we narrowly missed being hit by a car that could not stop; the car next to us was far less fortunate.

As we expected with the weather, birds were not easy to find. Counting on the west side of the Rouge River opposite the Henry Ford Community College and University of Michigan-Dearborn campuses, Cathy Carroll had the best birds. She had a Yellow-bellied Sapsucker, which has only been found on two previous counts. She also had the only Golden-crowned Kinglets of the day (found on five previous counts), as well as the only Brown Creepers and Northern Flicker. Her best bird was probably this forlorn-looking, snow-covered American Black Duck in the river near Dearborn's Ford Field. This is a species that is getting more and more infrequent in the city.

American Black Duck.

While the weather was a notable cause for a lack of bird numbers, it was not the main culprit. This year the sunflowers on the Ford World Headquarters site were planted late and got caught by a frost while they were still in bloom, so they did not set seed. Last year, this field had thousands of birds, including 3500 House Sparrows. This year, all we had there was a single Northern Cardinal.

Sunflower field with Ford World Headquarters in the background. Inset shows
a frozen sunflower head that did not set seed.

The fields at Hubbard and Southfield have been planted in hay the last few years. Not much going on there, except for nearly 300 Canada Geese hunkered down in the stubble. One of them was familiar, a goose with a neck collar that we first found and reported during winter 2011. She was originally banded as an adult female in August 2002 on Akimiski Island, Nunavut. We used to see a whole flock of birds from this James Bay island in the winter around here, but she appears to be the only one left. Another 400+ geese were in another field at Rotunda and Schaefer, with more at the Ford Rouge Plant. This was the second-highest total of geese we've had on the count since 1999.

Besides the geese, not much in these fields. Our numbers of small songbirds, especially Dark-eyed Junco, House Finch, American Goldfinch, and House Sparrow are at or near record lows due to the lack of seeds in these field. We also usually have a wintering flock of blackbirds in these fields, and this is only the second count since 2003 we have not had any Red-winged Blackbirds.

Although I have not received any recent reports of wintering Peregrine Falcons in this area this season, we did have one fly from the Ford building north across this field in the morning.

The flat-line crow numbers continue, with only a single American Crow counted. We have not counted more than 18 crows on any count day since the West Nile virus hit the area in 2002.

American Robins furnished an interesting story, with a total of 653 being our second highest total in 20 years. As noted in my post regarding our fall banding season, the fruit crop was phenomenal this year, after a near-failure last year due to drought. Robins took full advantage of this and were found feasting on non-native Common Buckthorn and ornamental crabapples in various places throughout the city. In previous counts, about 56% of the robins on average are found on campus, where there they have primarily fed on buckthorn. This year, nearly all of the buckthorn and other non-native fruiting plants have been eradicated in the campus natural area, leaving robins and other fruit-eating birds to forage elsewhere. Only 6% of the robins on this count were found on campus. The only other year when the percentage was below 33% was last year when the drought wiped out the fruit crop; 8% of robins on that count were on campus.

In this region, there are not a huge number native plants with fruit suitable for songbirds that are available in winter. Climbing/Prairie Rose (Rosa setigera), American Bittersweet (Celastrus scandens), and Eastern Red-cedar (Juniperus viriginiana) come to mind. For better or worse, if it were not for generations of widespread planting of non-native fruiting plants, we probably would not have as many overwintering robins.

Oddly enough, we have never had Purple Finch on the count until this year. This is not an uncommon species, but we mainly see them here in fall migration, and they are gone by count day. Rick Simek found this one the previous week on campus, and was able to relocate it for a new count day species. This brings the cumulative number of species to 87 for the Dearborn portion of the count.

We ended the day with 48 pecies, which is two above average.

Fall 2013 banding season

Our 22nd fall banding season took place on 29 days from 15 August to 5 November. An average of 15 nets (12 meter equivalent*) were open an average of 4.6 hours per day. This is the fewest number of days we have been open in a fall season, although our modified hours were intentional -- we wanted to concentrate on maximizing the data we obtain on the fall diets of migrant birds.

Unfortunately, we also lost a 10-day period while we tried to live trap an abandoned cat that had found its way into our banding area. With the safety of birds coming first, we cannot have our nets open when we know there is a predator in the area. We brought this cat to the local shelter, where they felt it was possible it could be put up for adoption. Sadly, people dump unwanted pets here fairly regularly. This is tragic, as is the toll on wildlife taken by owned cats that are let outdoors. I've said it before, but it bears repeating: please keep your cats indoors!

Weather
Unlike some years, we did not lose much time to bad weather. I hesitate to complain, but the weather was almost too nice on banding days! The best banding conditions usually occur on calm, overcast days, often before an approaching weather front. This season, over 80% of the banding days were clear or mostly sunny.

Fall banding numbers often also have a lot to do with weather in the preceding seasons. Unlike the ridiculously wet 2011 spring and summer seasons, and the equally parched months of 2012, fall banding was preceded by a spring and summer of relatively normal temperatures and precipitation. April was cool and wet, while May was overall quite warm except for a late frost in mid-month. Average monthly temperatures for June-October were close to the recorded averages for the period 1981-2010. Precipitation for June-October was also close to average, except for August. That month, the rainfall total was nearly three inches above average, but nearly 2.5 inches of that fell on one day, August 12.

Last year's drought caused a serious lack of fruit on shrubs and trees during fall 2012. Nature often makes up for lost productivity, and did so this year. The fruit crop on most plants was abundant if not phenomenal. As noted in my last blog post, the wild grape crop was the heaviest I have seen in over 25 years. Anybody who has an apple tree in their yard can attest that after last year's near complete crop failure, apples were so plentiful that trees broke under their weight. The same was true for their very close relatives crabapples and hawthorns.

The primary non-native fruiting species here are buckthorns and bush honeysuckles. They all seemed to flower and bloom a little later than usual this year, perhaps impacted by the May frost. However, they had large crops.

I noted only two types of fruiting plants that seemed to have below-normal crops. Black cherries, which were one of the few trees that fruited well last year, took a break this year with virtually no crop. Eastern redcedars also seemed to set less fruit than usual.

Summary
As might be expected with a modified banding season, we ended up banding a modest 550 new birds and handling 87 recaptures of 58 species. This includes two species released unbanded, House Sparrow and Ruby-throated Hummingbird. A total of 741 birds were netted (which includes birds released unbanded). Our capture rate was 39.4 birds per 100 net-hours. Here is how this fall compared with the 21 previous autumn seasons:

	Fall 2013	Previous fall mean
Days open	28	50
New birds	550	1177
Total birds	741	1502
Capture rate	39.4	48.0
Species	58	69

The top ten bird species banded this fall (new captures only) were:

1. American Robin -- 118 (low; previous mean 189.7)
2. White-throated Sparrow --49
3. Common Grackle -- 35 (new high; previous mean 8.8)
4. Song Sparrow -- 33 (new record low; previous mean 55.3)
5. Gray Catbird -- 32 (same as last year, which was record low)
6. Yellow-rumped Warbler -- 28
7. Hermit Thrush -- 21
8. Cedar Waxwing --19
9. Nashville Warbler -- 16
10. Ruby-crowned Kinglet -- 15

Numbers and Trends
The high number of grackles is just a hit or miss event. We get very large flocks near our banding site; flocks of over 500 blackbirds, of which most are grackles, is not uncommon in October. They occasionally get flushed into the banding area, but often do not "stick" in the nets.

Banding hummingbirds requires special equipment and a permit amendment, so we release them unbanded. If we didn't, they would have come in at #2 on the list with 40 captured. Some may be repeats of the same bird, but there are often 3 or 4 in the nets at the same time throughout the season, so this is close to an accurate number. They are most often caught in nets adjacent to two plant species at which they nectar: Spotted Jewelweed, a native wildflower; and Glossy Buckthorn, a non-native shrub. The latter has small blooms from early spring through fall and I frequently see hummingbirds using these flowers.

This is the first year we have missed banding any Gray-cheeked Thrushes or Philadelphia Vireos. This may be due to the timing of our gap in banding. This is the third year in a row we did not band any Wood Thrushes. Some years ago, Wood Thrushes were common nesting species here. This is a species that is declining over much of its range, and their absence here may reflect those diminishing numbers.

Both Swainson's Thrushes and Gray Catbirds continued a long-term decline in our nets that I have written about previously. 

Last year I noted declines in our capture rate* over the last decade. For the first 13-15 years of banding, things moved up and down, but usually remained over 40 birds per 100 net-hours. The average for the years 1992-2004 was 51.6. Since 2005, there has been a pronounced drop. In fact, the drop was quite steep from 2005 to 2008, and since then it has more or less fluctuated in the 30-40 range.

Click to enlarge.

Two important things happened around 2005 that may help explain this: first, the bike path that runs through campus -- wrapping around 3 sides of the banding area -- opened. It gets a great deal of traffic. Second, we began experiencing canopy loss due to falling ash trees killed by the Emerald Ash Borer. This dramatically changed the character of the forested area at UM-Dearborn. Not only did it result in a different mix of trees and shrubs, but probably created a more open and inviting habitat for our increasing deer herd, which alter ecosystems themselves.

So many changes have taken place around our banding site over the years, including the construction of several nearby buildings, and a large, busy parking lot adjacent to the net lanes. Increased development, habitat changes at the site and landscape level, higher numbers of mammalian predators, weather events... it's not possible to tell what may be responsible for our declining capture rate. No doubt it is a combination of things, and we will be pondering the future direction of the banding program in the months to come.

Highlights
We have only banded 6 Golden-winged Warblers in the past 21 fall seasons, so this bird on September 10 was a treat, and our first since 2005.

The past ten years of so, Northern Waterthrushes seem to be a little scarce, and some years we do not band any. Even just the four we banded this fall was better than we've done since 2006.

An interesting Orange-crowned Warbler was banded on October 14. It had large, distinct dusky centers to its undertail coverts. This is a feature more characteristic of the subspecies that is resident in California, and I've never seen it on any of the birds I've banded here in migration. Bill measurement can be helpful in distinguishing subspecies, and while this one was a little large, it was within the high end of the range of the subspecies expected to pass through Michigan.

A Sharp-shinned Hawk banded in mid-September.

Recaptures
Twenty-three individuals of 9 species of passage migrants (those which do not normally nest or winter in this area) were recaptured. Sixty-five percent of them maintained or gained mass. Half of the birds that lost mass were sparrows. This is fairly typical of this site; insectivores and frugivores tend to gain weight, while seed-eaters tend to lose weight, or gain just small amounts.

We also recaptured 13 birds banded in previous years. The oldest was a female Northern Cardinal first captured in October 2001, making it over 12 years old. Another old bird was a female American Robin first banded as an adult in 2008. She is at least 6 years old. 

Seeds!
We obtained another 318 seed samples from 11 species of birds. This included two new "contributors": a Brown Thrasher (which had eaten pokeweed and grape) and a Willow/Alder Flycatcher (which ate honeysuckle). This brings our total sample size to more than 1,500. Over half are from American Robins, and other large percentages from Gray Catbird, Cedar Waxwing, and Hermit and Swainson's Thrushes.

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*In order to compare different locations or years that may operate the same number of hours but with more or fewer nets, capture rate is calculated by "net-hours." One net hour is one 12-meter net open one hour, or two 6-meter nets open one hour, etc. This rate is often expressed per 100 net-hours for more manageable numbers.

Weather statistics from the National Weather Service.

Update on fall banding and fruit research

We are a little more than halfway through our modified fall banding. This year, we are concentrating on obtaining as much data as possible on the diet of fall fruit-eating birds. Many bird species switch from a summer diet made up primarily of insects to a fall diet heavy in fruit. This abundant, easy-to-eat food source is particularly important to migratory birds.

After our research showed that migratory thrushes gain weight during stopover at our campus study site, the next step was to pinpoint what resources these birds were using while they were here. Fortunately, there is a reliable and low-tech way to find out: identify the seeds in their poop. (You can find more details by following the links above.) We began collecting samples from thrushes in 2007, and from all birds in 2009. As of the end of last year, we have collected samples from 1,208 birds of 16 species. That's nearly 8,000 individual seeds, of which fewer than a dozen have gone unidentified (see the post on our seed website for more information on how we identify seeds).

Although these seem like big numbers, we need to make sure we have large enough samples sizes from individual bird species during certain time periods to make sure we can do proper statistical analyses. This way, we hope to answer a number of questions, especially whether or not particular species prefers certain fruits and if some fruits help birds gain more weight than other fruits.

This fall, to maximize number of samples we have modified our usual banding routine. When we have done comprehensive migration monitoring, we begin banding very early in the morning, which is when we tend to catch the most birds. Typically, birds captured the first hour or so have not had time to eat much, so we did not obtain many samples from them. This year, we are starting later in the morning and staying open later in the day, providing more overlap with bird foraging. We'll also aim to spend more hours during peak migration/fruiting periods -- late September to mid-October. Overall, this means we will probably band fewer birds, but get more samples.

So far over the 16 days we have banded this fall, roughly a third of all birds have contributed a sample. If we only consider those species most likely to eat fruit -- the primary species are American Robin, Gray Catbird, Cedar Waxwing, and the thrushes, but there are others that eat fruit less often -- the percentage jumps to over 65%. We have collected over 500 individual seeds.

Fruit crops fluctuate from year to year. Last year, the very early spring warm weather and the summer-long severe drought devastated fruit crops.  This year much more normal rainfall and temperatures has resulted in bumper crops of fruit. Some are especially impressive: branches are sagging under the weight of crabapples (both wild and ornamental) and the wild grape crop is nothing short of phenomenal, the largest I have seen in over 25 years.

Not a vineyard! Wild grape crop.

Many factors go into fruit choice in birds: fat, sugar, protein, and micro-nutrient content; size and color; pulp-to-seed ratio; and abundance are just a few. Not surprisingly, the dominant seed in our samples this fall so far is grape, present in 65% of samples. As the crop is depleted and other fruits ripen, the proportion will decline, but no doubt it will be higher than any other year so far. In past years the percentage of grapes has ranged from 5 to 19%.

Grape seeds provided by an American Robin.

This winter we will be doing our first statistical analyses of our samples to see what our data looks like. Stay tuned!

Summer banding 2013

RRBO has done very little summer banding over the years, as we have not had any research projects that require banding during the breeding season for quite some time. This summer, however, our catbird project had us out in the field catching catbirds...and of course we banded whatever else we caught while doing so.

First, we successfully captured enough catbirds to carry all 26 of the geolocators obtained through Dr. Bowlin's grant. On campus, we did targeted netting in a location near Fairlane Lake by setting up a few nets in the midst of the territories of several pairs of catbirds. I also set up our usual fall banding area over a month earlier than usual and the bulk of the catbirds were banded there. In total, at UM-Dearborn we banded 21 catbirds: 7 adult males, 5 adult females, and 9 hatching-year birds. We also captured 5 catbirds (2 adult males, 2 adult females, and 1 hatching-year bird) at a remote site off-campus in Washtenaw County.

Aside from catbirds, we banded 72 other birds of 16 species. The highlight was two hatching-year Orchard Orioles caught in the same net on July 24. This doubles the number of Orchard Orioles banded on campus since 1992; the other two birds were adults caught in the spring. This is an uncommon but annual species here. This year, they seemed more numerous than usual, and apparently nested on campus or close by.

One of the young Orchard Orioles banded this summer.

An adult female American Redstart banded on July 17 was a surprise. There was no physical evidence that she had nested, but it was only our second July record.

We tend not to band many Yellow Warblers in the fall (our 21-year average is 3) because they start to move south quite early in the season. A total of 5 for our modest summer banding was a nice number.

My impression is that House Wrens are having a good year, and we banded a dozen. This is just under our fall seasonal average. We'll see how the fall numbers look.

Our fall banding season begins in mid-August. We will be concentrating on maximizing the data we obtain on the fall diets of migrant birds. We will be banding fewer but longer days, and focus on times of peak bird movement and wild fruit set. After last year's drought-induced fruit crop failure, most fruiting plants are loaded this year. Because we had prolonged cool weather this spring, ripening is a little late, but it should be a very interesting season.

Update on catbird research

In 2011, RRBO embarked on a collaborative research project with Dr. Melissa Bowlin, a member of the UM-Dearborn Natural Sciences faculty. Dr. Bowlin had a number of geolocator devices left over from a previous project. Geolocators are tiny devices that measure light levels. This data can be used to calculate latitude and longitude when compared with sunrise and sunset times and light levels at noon in different geographic locations. They can be placed on a bird, and if the bird can be recaptured the following year, the data can be downloaded and migration routes, pace, and destination can be determined.  In 2011, we placed 11 geolocators on catbirds. In spring 2012, we resighted 3 birds with devices, and recaptured 2 of them.

We did get data from the 2 retrieved geolocators. As it turns out, the data was not high quality; not only do catbirds spend a fair amount of time in shaded areas, but the light-collecting stem on the devices we used was a little short and we suspect ended up being covered by feathers a good amount of the time. Without a good reading on the light, the data from one was deemed inaccurate. The other bird seems to have wintered in Florida -- which is unexpected as preliminary data from other researchers (based on banding and geolocators) indicates that Midwestern-nesting birds winter in Central America. We put the geolocator on this bird on September 29, 2011, it appears to have left Dearborn on October 12, arrived in Florida on the October 16, left the wintering grounds on March 30, 2012, and arrived back in Dearborn on May 8, 2012. We recaptured it May 17, 2012 (here's the story of its recapture).

In fall 2012, we put 2 more geolocators on birds, but did not see any birds with geolocators in spring 2013, despite a lot of patient observation of the catbirds on site.  Earlier this year, Dr. Bowlin received a grant to purchase 26 new geolocators with longer light-collecting stems better suited for catbird study. You can see the older device below in the top picture, and a newer one with the longer "stem" in the bottom photo. They both weigh the same, 1 gram including the harness.

During my spring bird surveys, I spent time locating territories of catbirds that I thought would be easiest to catch and re-find next year. Two of Dr. Bowlin's students, Kelli Gutmann and Quen Watkins, then staked out these birds to see where they tended to hang out so they could be captured with a minimum of fuss. I also set up our regular fall banding site, and began banding a month earlier than usual.

We have had good success so far this summer. We have put 14 geolocators on resident catbirds. Even more exciting, one of the birds I recaptured was a male with a geolocator from 2011! The batteries on the devices can last for 2 years, so if it is good quality we could conceivably get 2 years of data from it. 

We feel confident we can catch enough catbirds for all of our devices, and look forward to finding out what routes they use on migration; if the routes differ for males and females, or adults and young; where the birds stop during migration and how long they stay at each stopover; and where they spend the winter. Stay tuned for more updates!