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.

Winter Bird Population Survey 2014-2015

The 23rd year of RRBO's Winter Bird Population Survey has been completed. December started out pleasantly but the survey season ended with a snowy and bitterly cold February. Weather aside, it was a fairly average year. The 14 survey days over the late December to late February period was typical. Surveys totaled about 23 hours, which is 6 hours below the 29 hours that are average, but represent the shortage that took place on our Christmas Bird Count day.

The 34 species tallied was a little below the 22-year average of 38, but can be partially explained by some habitat changes and restrictions. Access to the Rouge River behind Fair Lane Estate was greatly restricted due to being fenced off for riverbank restoration; vegetation along this area also removed. The river was frozen much of the period, and no waterfowl were counted after January 1. No Belted Kingfishers were recorded; they have only been completely missed on a few other counts.

Heavy construction activity along Fair Lane Drive also impacted bird activity along eastern edge of survey area. This construction will be continuing through summer, and likely also have an effect on spring surveys.

Eleven species were found on all 14 survey days. In descending order of abundance they were: House Sparrow, House Finch, Northern Cardinal, Blue Jay, Black-capped Chickadee, Dark-eyed Junco, Downy Woodpecker, White-breasted Nuthatch, Tufted Titmouse, Red-bellied Woodpecker, and Hairy Woodpecker -- all feeder birds.

Despite the availability of feeders, most sparrows were recorded in numbers well below average. Only a single Song Sparrow was recorded, while the previous season total average is 13. One or two American Tree Sparrows were recorded several times, but the previous season total average is 34. White-throated Sparrows have been common winter residents here, especially over the past decade. A total of 25 were counted this year, with an average per survey of 1.7, the lowest numbers since 2002. The previous 22-year means were 80 per season and 6 per survey; these averages since 2003 were 157 and 9. Juncos were also counted in below average numbers, although not as drastic. I'm not sure exactly what might have contributed to the depressed numbers of ground-feeding seed eaters, except that a lot of understory vegetation has been removed and perhaps there is less cover.

Fruit-eating birds were largely absent. No Cedar Waxwings, Hermit Thrushes, or Yellow-rumped Warblers were recorded. Most days there were no American Robins present, the maximum number on a survey day was 3. This represents the second lowest number of American Robins in 23 years. Fruit-eating species were generally scarce on local winter bird counts this winter, so it's hard to tell what impact the removal of fruit-bearing non-native trees and shrubs that was undertaken by the university may have had on these numbers.

The highlight was probably the Pine Siskins that were present in small numbers through mid-January. They moved on from here (and other places locally) and had not moved back through on their way north by the time the survey period ended. This was the only one of the "irruptive" species present on campus this winter.

All the numbers from this year are on the RRBO web site, along with past counts and the history and methodology of the survey.