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.