Why are Yellow-headed Blackbirds rare in Michigan?

Male Yellow-headed Blackbird singing, Wolf Lake Fish Hatchery. Photo 1 May 2010 by Tim Tesar.

A Yellow-headed Blackbird, a rare bird in Michigan, was seen near the end of April at Wolf Lake Fish Hatchery.  The Fish Hatchery is west of Kalamazoo, a few miles over the Kalamazoo-Van Buren County line.  The bird was first reported on 30 April.   I drove out Sunday morning, 2 May, to try to get a look.

It wasn’t hard.  The bird was on territory, hence easy to locate, and also easy to identify with its bold yellow, black, and white plumage.  On the perched bird, the white is seen as a narrow stripe on his side, but when he flies it flashes as a sizable patch on the leading edge of the wing.  Females don’t have the patch, but there were no females evident.

I watched the bird fly back and forth between several perches, singing fairly often, occasionally chasing a Red-winged Blackbird.  Male Yellow-headed Blackbirds are handsome birds, but their song is not handsome exactly, or pretty or melodious–more like odd, but well worth hearing for its oddity.  The recordings readily available on the web don’t quite do justice to the long, loud, vibratory parts of the performance, but you can get a general idea from the example included at the Bird Watcher’s Digest website.

Yellow-headed Blackbirds tend to be polygynous and colonial.  I wasn’t sure whether one lone male would be able to attract a female but I was hoping he’d get lucky.  But as far as I know no female was ever seen, and by some time around the middle of May, the male was gone.

Michigan accounts of the Yellow-headed Blackbird tend to start with a statement to the effect that species is relatively new as a breeding species in the state. It’s true that the first confirmed nesting in the state didn’t occur until 1956.  Four birders visiting the Upper Peninsula in late June followed up a report of Yellow-headed Blackbirds in a large marsh in Gogebic County, a few miles from the Wisconsin border.  They found two males and five females and spent some time hunting for nests but didn’t find any. However, one of the birders returned the next morning and found two nests.

The finder of the nest was Larry Walkinshaw.  Who else would it have been? Walkinshaw was a Battle Creek dentist who was also one of the great field ornithologists of the era. Part of his research repertoire was a seemingly uncanny ability to locate nests.  I wrote about Walkinshaw in an earlier post.

Discovery of the first Lower Peninsula nest followed four years later.  A colony of seven nests at a cat-tail marsh in Saginaw Bay was found in early June 1960 by Bob Grefe and fellow birders in Bay County near Quanicassee.

By the mid-1980s (1983-1988) The Atlas of Breeding Birds of Michigan (Brewer, McPeek, and Adams, 1991, Michigan State University Press) showed confirmed nesting in 13 townships–4 around Saginaw Bay and 2 more not far away, 4 in the Upper Peninsula, and 3 in Muskegon County on the west side of the Lower Peninsula.  Six more townships had summer birds that were probably nesting, but confirmation was lacking, and 10 more townships had birds possibly nesting.  (The uniform breeding codes and criteria for breeding-bird atlases are here.)

These observations could fit a pattern of arrival as a breeding species in Michigan sometime in the 1950s followed by spread and establishment as a regular but rare and local member of the breeding avifauna in the next 30 years or so.  But in preparing the chapter “Original Avifauna and Postsettlement Changes”  (pp 33-58) in the first Michigan breeding-bird atlas, I realized that the view of Yellow-headed Blackbird as a recent immigrant was incorrect or at least incomplete.

The blackbird, I concluded, is one of a small group of Great Plains species that occur in the grasslands and grassland marshes and that extend their geographic ranges when there are severe droughts in the Great Plains. It seems likely that carrying capacities for these birds drop as ponds and marshes shrink and grassland habitats deteriorate. Surplus birds disperse, some coming east.

The important droughts of the 20th century were the Great Drought of 1933-1940 and the 1950s drought, which was most severe in the Great Plains from about 1953-1957.  The first recorded nests of the Yellow-headed Blackbird in Michigan came during the invasion of the 1950s.  What happened in the 1930s drought?

During and just after the drought years of the 1930s, Yellow-headed Blackbirds were seen in the breeding season at a few places around Michigan after being virtually absent through the early part of the 20th century.  No nesting was recorded, but nesting did occur just to the southeast, in Ohio, at a site that has since become much more famous for other reasons–Magee Marsh (Lucas Co.). Nesting was first confirmed there in 1938, but summering birds were present from 1934 to 1941. After that, no summer birds were reported from the area around Sandusky Bay until 1960.

What of other, earlier droughts?  As we go back in time, the ornithological evidence gets scantier but follows the pattern of a bird that, except for occasional stragglers, is only here in the eastern part of the Midwest during tough environmental times in the Great Plains (and for a few years thereafter).

Here’s some more evidence.

Morris Gibbs, one of Michigan’s earliest ornithologists, a Kalamazoo resident, and a very smart guy, wrote in the early 1890s that the Yellow-headed Blackbird occurred in extreme southwestern Michigan and probably bred.  This statement was discounted by most later compilers of Michigan bird lists, although a specimen, the first for Michigan, was taken on 17 May 1890 in the Upper Peninsula adjoining Wisconsin (Dickinson Co.).

What is definitely true is that the species nested commonly in the 1870s-1890s in the large marshes around Chicago, Illinois, including Indiana marshes very close to the southwest corner of Michigan. In the summer of 1871, one egg collector took over a hundred Yellow-headed Blackbird eggs in the marshes along the Calumet River in Indiana southeast of Chicago and within 30 miles of the Michigan line.

This period of relative abundance in northwest Indiana and possible nesting in southwest Michigan was a time of two 19th century  droughts, one in the 1870s, and one from the late 1880s to about 1896. Then, in the early 20th century, populations in the marshes of northwestern Indiana faded to zero.

The second drought, the one from the late 1880s to 1896, was the one that gave rise to the slogan, “In God we trusted, in Kansas we busted” and led to the sod-busters dispersing from their Great Plains farms like Yellow-headed Blackbirds from a dried-up prairie slough.

2.  As we’ve noted, the first Michigan breeding bird atlas documented a substantial Yellow-headed Blackbird population.  But the atlas period included the third and last of the 20th-century droughts (1987-1989).  So the comparative abundance of the bird at that time fits our model very well.

I mentioned that other species seemed to follow a similar pattern of breeding season occurrence in Michigan corresponding to a cluster of drought years in the Great Plains.  The others that I noticed were Wilson’s Phalarope, Western Meadowlark, and perhaps a few more, such as Western Kingbird and Brewer’s Blackbird.

I would add one more thing:  Michigan is as much a part of the geographical range of these birds as it is for the robins and chickadees that are here in numbers every year.  Droughts are an expectable occurrence in the Great Plains.  When habitats deteriorate there, the lakes and marshes of Michigan, Illinois, and Ohio are important refuges for birds that would fail to breed and possibly would perish if the wetlands of the eastern Midwest were unavailable.

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