Friday, February 27, 2009

A tropical adventure

A trip to anywhere in the tropics is always high on my list of great things to do. Over the last 7 years or so, my husband Darrin and I have volunteered our time to a number of organizations operating in the tropics -- usually doing bird surveys or otherwise assisting local ecologists. Our newest opportunity will be next week in Nicaragua.

The bulk of our time will be spent in the montane coffee-growing region of Matagalpa. Some of you know that I have a passion for excellent coffee, and write an entire website devoted to the issues surounding sustainably-grown coffee. Coffee grown under shade in an eco-friendly manner is critical for tropical biodiversity, and for so many of the migrant birds that breed in North America and winter in the tropics. Those of you who are members of Cornell's Lab of Ornithology may have seen the recent article on shade coffee in BirdScope in which I was quoted.

Darrin and I have been invited to participate in an on-going bird banding project initiated by the North Carolina Museum of Natural Sciences. In Matagalpa we will be visiting Finca Esperanza Verde (FEV), a shade coffee farm near the village of San Ramon (click on the map to enlarge). We will be banding first with other researchers, and then assisting a group of college students from North Carolina. This project helps to document the birds that use the finca -- both resident species and those that nest in North America but winter in the area, or are on their northbound migration. For example, the most frequently banded North America wintering species at the finca is the Wood Thrush. One of our North Carolina colleagues, Curtis Smalling of North Carolina Audubon, will be working specifically with Golden-winged Warblers.

We will not only band birds, but of course also observe and census birds at FEV. Counter Culture Coffee in Durham, NC sources coffee from FEV and other farms in the San Ramon area; coffee from FEV was one of the top ten coffees in the prestigious 2007 Cup of Excellence program. I'll be providing feedback to Counter Culture about the birds on the farm. I'm excited to admit that I assisted Counter Culture with their choice of the Emerald Toucanet as the bird on their Cafe San Ramon packaging (left). Darrin and I have seen this species at other shade coffee farms in Panama, and knew it was on the finca's bird list.

After we leave FEV, we will be traveling back toward the colonial city of Granada, near the shores of Lake Nicaragua. After a few birding stops en route, including another shade coffee farm, we will be settling in for several days at Domitila, a private wildlife reserve. Domitila represents one of the last and best preserved dry tropical forests in the country. At both FEV and Domitilia, we will be conducting insect surveys, focused on dragonflies and damselflies, to assist with the Insects of Nicaragua inventory being conducted by the Museo Entomológico de León (Entomological Museum of Leon). There is still much to be learned about Nicaraguan insects now that the country is peaceful after so much civil war. We can attest that even well-studied countries like Panama turn up surprises. On our last two trips there, we photographed at least one undescribed species of damselfly, and took the first photograph of a live specimen of another species that was described over 30 years ago. Who knows what we might turn up in Nicaragua!

When we return, I will be writing an article on the importance of shade grown coffee to birds, incorporating my experiences, for Birder's World Magazine.

Of course, I will also share as much as I can with you here at Net Results. Be patient: for most of the trip, we will not have Internet access (or electricity, or hot running water!), so I will have to wait to return home to post updates when I am not busy catching up and getting ready for spring migration.

Monday, February 23, 2009

Winter Bird Population Survey, Year 17

I have always hated winter. I don't like being cold and have always found Michigan summers far too short. But here I am, and when life gives you know the story. When I first started working here at UM-Dearborn, I began a standardized winter bird survey. This makes it the longest-running survey by the Rouge River Bird Observatory. I have just completed year number 17. I cleverly called this endeavor the Winter Bird Population Survey, since it was patterned after the Winter Bird Population Study protocol, developed many decades ago. In short, I walk through the campus natural areas roughly twice a week between 20 December and 20 February, always completing my survey before noon, and record every bird I encounter. The final tally includes the average number of individuals encountered per visit (abundance) and the number of visits in which a species was encountered (frequency of occurrence). This all sounds very mundane, and generally it is in the short run. But the beauty in long-term data is often not seen for many years. In 1992, who would have anticipated the importance of counting such a common and ubiquitous species as the American Crow? For an entire decade, I dutifully counted crows, woodpeckers, and chickadees, birds I encounter so often that I sometimes had to concentrate on actually "seeing" them. The occasional Northern Shrike or even Fox Sparrow were much more fun and interesting. Then came West Nile virus and suddenly -- no crows. The profound impact of this disease on local crow numbers would not be quantifiable without the years of baseline data. After ten years of fluctuating but generally stable numbers, the average number of crows per visit was just under 12. The winter after the first breeding season in which West Nile virus occurred (2002), I counted a total of only 18 crows, which worked out to 1.2 crows per visit. I haven't counted double-digits over an entire winter survey period since then. This winter, I only recorded crows on one survey, when I saw four birds. The average for the past seven years has been 0.5 crows per visit, a drop of 96%. My many years of data have also revealed interesting trends in the numbers of woodpeckers, once ash trees began to succumb to Emerald Ash Borers. I'm also able to look at numbers of overwintering robins and how their numbers change over the course of a season and the decline of American Black Ducks here in winter. Other species don't seem to reveal anything particularly compelling...yet. In the 17 years of the survey, I've averaged 38 species a year. This year I had a record 45 species. Remarkably, four were new to the survey:
  • Common Goldeneye (photo below) -- not unusual in winter on the Rouge River, but a first for campus;
  • Red-shouldered Hawk-- first record in Dearborn for December or January;
  • White-winged Crossbill --part of the remarkable irruption I discussed in my last post; and
  • Brown-headed Cowbird.
The cumulative total for the WBPS is now 67 species. Thirty-one species have been seen in 12 or more years (70% of the years) and are thus considered our core winter residents. Eleven species have been recorded only once, with the rarest being last year's Hoary Redpoll. I tend to begrudge every time I have to bundle up and spend the next several hours in the cold counting birds. I knew when I started the WBPS that a long-term data set would have applications in tracking numbers of resident birds. But already seeing interesting and relevant results has certainly helped motivate me to get out the door on some of those bitter mornings. Hoping to count crows.

Tuesday, February 10, 2009

A winter of finches

Every so often, a long cold winter is made worthwhile when we get visitors from the boreal north. I'm talking about "winter finches." A number of species move south when their preferred food source becomes scarce in the northern parts of their range. These birds all have a few favorite tree seed species, and trees tend to produce seeds in cycles (up for one or more years, down for another one or a few). This helps us predict when we might see certain winter finches, and in what numbers. The folks in Ontario create an excellent, detailed winter finch forecast every fall. I encourage you to read a recent copy to get a feel for which bird and tree species are involved.

This winter has been terrific for winter finches. The most impressive and special has been the push of White-winged Crossbills. While they are found nesting in Michigan's Upper Peninsula, they are very rare in southern lower Michigan; Dearborn had only a handful of records before this winter. This year, they've been found in nearly every county and in big numbers. It's unlikely an event like this will ever occur again in my lifetime. I've had big flocks in my neighborhood, even my yard, but a reliable group has been working the Douglas firs at a local office building (White-winged Crossbills specialize in soft cones like spruces, hemlocks, and some firs). Here is a male (above) and female (below) taken there by Mike O'Leary.

Pine Siskins were some of the first finches to arrive in early winter and have stayed around in large numbers -- they are often present at feeders. While a couple individuals are found every year, we have not had this type of invasion here in Dearborn since the late 1970s. Pine Siskins will sometimes nest in southern areas after a big invasion year, so I will not be surprised to hear of some breeding in southeast Michigan this summer. We have had only a handful of siskins at any one time here on campus, but scores of them at our feeders at home a few miles away. So far, we've banded over 60 the last couple of weekends. Some are dull, but some are quite beautiful when you get to take a look in the hand.

Common Redpolls have also been very abundant. On campus, they have been busy extracting the tiny seeds out of the small cones on the black alders around Fairlane Lake. Few have come to the feeders. At home, we've had only a few at our feeders as well. Here are a couple of males -- young males and females tend to have little or no pink on the breast.

Last but not least is Purple Finch. We usually see a few Purple Finches every fall during migration. This fall was no exception, but we have heard few reports of many Purple Finches in the area in the subsequent months. It seems like they passed by, went somewhere else, or didn't make it this far south in any numbers. This is the only one I've seen, a male at my feeder. That's a male House Finch below it. Notice the distinct curve to the upper bill of the House Finch. It's quite straight in a Purple Finch, and a good structural clue to telling the two species apart. Here is a guide to identification.

I admit, I loathe winter. But knowing I could easily find and observe these special species has made going out not only bearable, but actually a lot of fun.

Wednesday, January 21, 2009

European Goldfinch: established in the U.S.?

Important note: Although RRBO has ceased operations, I am still collecting data. Please see this page for the latest update. 

In the fall of 2002, Ford Motor Company planted sunflowers on a 20-acre lot they owned at Hubbard and the Southfield Freeway (M-39) service drive, near their world headquarters. Ford has continued to plant sunflowers, sorghum, and/or a wildflower mix on up to 10 properties scattered across Dearborn. 

The fields have always attracted a lot of birds -- I wrote about the numbers seen on this year's Christmas Bird Count. The very first winter the original field hosted an unusual bird: a European Goldfinch (Carduelis carduelis), a bird not native to North America. European Goldfinches are common in the pet trade, and it's not too unusual to hear about sightings of escaped or released pets. Unlike members of the parrot family, European Goldfinches are very hardy and can survive northern winters. The sighting occurred during a time when I had been hearing more and more reports of European Goldfinch sightings, especially in the Chicago area. Curious, I posted a page on the RRBO web site requesting sightings from the upper Midwest. I also kept my eyes on the various Internet birding lists and regional publications.

That there were a lot of European Goldfinches out there readily became apparent. I compiled over 400 reports, of which 298 were from Illinois, Wisconsin, Indiana, and Michigan. There was a clear concentration in southern Wisconsin and northern Illinois, a pattern of radiation from the "epicenter" that was more pronounced north than south, and a smattering of reports over the rest of the four states.

It is believed that the bulk of these European Goldfinches -- as well as a handful of other European cage bird species that were reported in the same areas -- originated with a bird importer in the greater Chicago area. From a number of independent reports I received, this importer had apparently deliberately released these species on more than one occasion over time. Believe it or not, as long as the birds are legally imported, there is no federal law prohibiting their release, even if they are not native.

Since 2003, there have been reports of nesting European Goldfinches in northern Illinois. They may also be nesting in southern Wisconsin. Great Tits (Parus major), another one of the species involved in the alleged releases, have also nested in southern Wisconsin and northern Illinois! European Goldfinches nest earlier in the year than American Goldfinches and appear to be ecologically benign, although non-native species frequently end up having unanticipated impacts on ecosystems. Whether the breeding population will grow and persist is not known. In the early part of the 20th century, there were a couple of established colonies in New York, founded by deliberate releases. They eventually died out. However, the proliferation of non-native plant species -- many of which are the natural foods of European Goldfinch -- may prove to be a boon for the species this time around.

I don't believe the majority of the Michigan sightings (or the many Ontario reports I've gotten) of European Goldfinches are attributable to same source. The geographic and chronological patterns do not seem to fit. Some are likely just escaped pets. Many others may be deliberately released birds. Some pockets of reports came from areas with higher populations of people that practice eastern religions, which sometimes advocate setting birds free to accrue merit in the afterlife. Employees at my own local pet store, which often carry European Goldfinches for sale, reported to me that these and other cage birds are sometimes purchased by people of various ethnic backgrounds with the intention of releasing them. I presume this is the source of the Dearborn European Goldfinch.

I ended up writing a detailed account of the reports I received, including background on the ecology and history of European Goldfinches in the U.S. and additional information on their future, in a paper that was just published in North American Birds; you can click on the link to download a PDF copy:

Craves, J. A. 2008. Current status of European Goldfinch (Carduelis carduelis) in the western Great Lakes region. North American Birds 62:2-5.

List of updates on this post:

  • June 2009: Nesting European Goldfinch in Illinois.
  • July 2009: Nesting European Goldfinch in Wisconsin.

Photo of European Goldfinch in France by Daniel (ParaScubaSailor) at Flickr under a Creative Commons license.

Tuesday, January 6, 2009

Dearborn CBC

RRBO has been coordinating the Dearborn portion of the Detroit River Christmas Bird Count (CBC) since 1995. The count is held each year on New Year's Day. This year, the 53 species found in Dearborn on count day tied our previous high total. A Wood Duck at the Ford Rouge Plant was a new species for the Dearborn portion of this count. The big news this winter has been the push of White-winged Crossbills into our region. Unfortunately, none were found on count day, but they were found in several locations in the days following the count, so they are added as "count week" birds. This is also a new species, bringing the cumulative species total to 85. Here's a photo of a male crossbill taken by my husband Darrin O'Brien in our east Dearborn back yard on 3 Jan. We were lucky enough to have a flock of 26 crossbills, and a few Pine Siskins, visit the spruce trees.

One of the annual challenges is counting the hoards of birds that hang out at the nine or so sunflower/wildflower fields planted by Ford Motor Company around Dearborn. After trying several strategies, we now devote a single team (usually Darrin and I) to spend most of the day concentrating on getting accurate counts of birds in the fields. This helps prevent double-counting if the birds move from field to field, and allows a team to spend the necessary time to make good estimates on what are sometimes very sizable flocks of sparrows or finches.

This year was made a bit easier, as the largest field, on the south side of Hubbard at Southfield, was not planted this year. Another, at Southfield and Rotunda, was plowed under in fall. Still, we had our work cut out for us. The photo below is the field on the north side of Hubbard at Southfield. I've underlined myself in red! This field had the most birds this year. It took us a long time, but we feel comfortable with our count of over 2400 House Sparrows here. These fields have a lot of benefit to wildlife, but the downside is that they have certainly helped boost the House Sparrow population, which has skyrocketed in the last few years. Our final total of nearly 3500 House Sparrows set a new high record.

Another group of birds that has begun to overwinter in these fields are blackbirds. Last year the Rotunda and Southfield fields had a staggering 1300 Brown-headed Cowbirds. This year the blackbird flock was more modest. Here's about half of them. Most were Red-winged Blackbirds, along with some cowbirds and a single Common Grackle. Raptors have taken advantage of all the small birds in these fields, and once again we have a wintering Merlin here. We had plenty of opportunities to watch it hunt!

If we have time in the afternoon after going through the sunflower fields, Darrin and I hit a few other spots. We had this female American Kestrel dining on a mouse near Miller Road and Wyoming.

It's always nice to have a hot cup of coffee when adding up the numbers back at the EIC on campus. Here I am with Jerry Sadowski (in the Crocs that match the rest of his outfit!), Greg Norwood (in ball cap), and Gary Hutman, all veterans of the Dearborn count. Jerry and Greg are in charge of counting on campus, and Gary covers Rouge Park (in Detroit, but within the larger count circle).
The final story is the continuing saga of the lack of crows since West Nile Virus wiped them out in this area. Up to 2003, it wasn't unusual to count well over 200. That year, we counted 18. Since then, we haven't had more than 8 in any year. Blue Jay numbers, however, have remained pretty constant.

You can view the results of all past Dearborn CBCs on the RRBO web page.