Tuesday, November 18, 2014

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. 


Friday, November 14, 2014

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.

How you can help

RRBO has over 2,000 people who follow us on Twitter, Facebook, or subscribe to our newsletter. Our $20,000 goal can be reached if everyone pitched in just $10! If everyone could spare $50 it would give us breathing room, and give RRBO the resources we need to accomplish our research goals.

You can visit the Support page on the RRBO web site for instructions on how to download a donation coupon, or donate online. If you'd like to donate via credit card directly through the University's secure web site just click this link. Thank you!


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.
 

Thursday, October 9, 2014

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. I took a short recording -  click here to listen (it's a m4a file, but I can play it with Windows Media Player).

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.

Friday, September 12, 2014

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.

Somewhere in the mix, I have to squeeze in our annual fundraising campaign. The goal is to increase support by 30% in order to avoid further cuts and furloughs. But you don't have to wait -- visit this page on the RRBO web site to learn how to make a gift today!

Monday, June 9, 2014

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!



Wednesday, April 30, 2014

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.

Wednesday, February 26, 2014

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.

On the RRBO web site, you can find the full results of all 22 years of surveys, along with information on the protocol.

Friday, January 10, 2014

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.