Sunday, December 27, 2009

Rockwood CBC: Lots of Refuge properties

Dawn at Humbug, looking from Jefferson Avenue toward the Trenton Channel Power Plant.
Since 2004, RRBO has been participating in the Rockwood Christmas Bird Count (CBC) by surveying the Humbug unit of the Detroit River International Wildlife Refuge (DRIWR). Last year I gave a little background on this count and our coverage of Humbug. This year, my husband and I once again counted at Humbug, but we also made whirlwind stops at five other units of the DRIWR that are within the Rockwood count circle. Several are fairly new units that are under restoration and the USFWS wanted to see if waterfowl were using them. Since the units are not open to the public and we have a special use permit for various projects, we offered to give them a look. Although it rained on Christmas Day, the next day most standing water had refrozen, limiting waterfowl use. That was probably not a bad thing. If the water had been open, we'd still be counting. As it was, this was more of a reconnaissance mission. Now we know the logistics, and can make recommendations on how the units should be covered in the future. We ended up walking over ten miles, but only tallied 44 species, owing to our quick work at most of the units and drive time between them. It was nice to see a total of 10 Bald Eagles at 4 of the 6 units. A Killdeer at the Humbug unit was probably our best bird. Great Blue Herons are always found in good numbers at Humbug, since there is always some open shallow water there due to discharge from the Trenton power plant just north of the property. We had 49 herons at Humbug, close to our record of 53 in 2004. We had another 19 roosting around the old quarry pond at the Gibraltar Bay unit on Grosse Ile (more on the units below). Sparrows in general seemed sparse, although we had two Fox Sparrows at the Brancheau unit. All of our 148 American Robins were at Humbug, feeding on Common Buckthorn, honeysuckle, and perhaps some rose hips. We completely missed any blackbirds, Carolina Wren, Cedar Waxwing (also missed by all other teams on the American portion of the count), and, sadly, American Crow. Very few crows were found on the count; this species does not seem to be recovering from West Nile Virus. Here is a run-down of the units. 
  • The Humbug Marsh unit is in Gibraltar and Trenton. At least half of the northernmost section was rehabilitated over the summer, and was either unvegetated or iced over, making that part quick work. I've attached a number of photos to this route, so hover over the map, and click on the first icon on the right to go into slideshow mode. We had 29 species here.
  • The Gibraltar Wetlands unit is very near Humbug, behind the high school at Jefferson and Woodruff Road in Gibraltar. Since it was frozen and we only had a few birds there, I did not include this in EveryTrail.
  • The Gibraltar Bay unit is the former Grosse Ile Nature Area (and a one-time Nike missile site) at the south end of Grosse Ile. We mostly went for waterfowl. 22 species.
  • The Fix unit was the furthest south we traveled, and is adjacent to the Fermi nuclear power plant in Monroe Co. These old farm fields have been planted with prairie and grassland vegetation, but were unvegetated this winter. We had 15 species here, including our only Winter Wren. More info here.
  • Walking a muddy dike at the Fix unit, with the cooling towers of the Fermi nuclear plant as a backdrop.
  • The Brancheau unit is north of Fix, on the other side of Swan Creek. These fields will also be planted for wildlife. A pump system has been installed to bring in water from Lake Erie so the fields can be managed for waterfowl or shorebirds. 17 species.
  • The Strong unit is just south of Pointe Mouille State Game Area. It also has old farm fields, and a large wetland bordered by dikes. The main dike is tall and grassy, with fields and woods on one side, and the wetland on the other. In many places Phragmites makes it hard to see into the wetland. We had our Fox Sparrows here, along with most of our American Tree Sparrows. We also had a Sharp-shinned Hawk, less common than Cooper's Hawks here in winter. 24 species.
The final dike walk of the day, this one at the Strong unit.
Realistically, covering all these units effectively takes more than one group of people. In the future, we will probably continue at Humbug and then concentrate on Gibraltar Wetlands and Gibraltar Bay.

Sunday, December 6, 2009

House Sparrow madness

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

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

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

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

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

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

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

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

Thursday, December 3, 2009

RRBO bird banding video

This video was produced in 2001. Although I enjoy having people see me so much younger and thinner, it could use an update as it was shot on film and the digital conversion isn't very high resolution. Nonetheless, it gives you an idea of how and why we band birds. We use this to introduce students, program participants, and visitors to the banding process.

Banding at RRBO from Julie Craves on Vimeo.