Breeding Henslow's Sparrows
in Lincoln, Massachusetts, 1994
A rare and erratic breeder in Massachusetts
by Stephen F. Ells
BIRD OBSERVER, Vol. 23, No. 2, 113-115 (April 1995)
The Henslow's Sparrow (Passerherbulus henslowii) in Massachusetts is now a rare or very rare, erratic, and local breeder near the edge of its historic range. In the past it arrived in the state about May 6, although in 1983 it was observed on April 30. Its most recent breeding records were two pairs in Leicester at the Worcester Airport in 1973 and 1974. Other suggestions of breeding were four males that were singing in West Newbury from May 18 to August 10, 1974, and four males singing in Windsor in August and early September 1983. The sparrow probably leaves its breeding grounds in late September and October (with three winter records). [ Return to Bobolink Home Page if you want to ]
Lincoln's wildlife-friendly agricultural practices
In 1994 I spent time in Lincoln's hayfields, studying Bobolinks. One of those fields was the seventeen-acre Farm Meadow, a high-quality hayfield under the control of the town's Conservation Commission. In 1994 the Commission had for the first time set aside a five-acre portion of the field as a "cut-later" sanctuary to protect the Bobolink young. The cut was to be delayed until at least July 15 [See S. Ells, Bobolink Protection and Mortality on Suburban Conservation Lands, Bird Observer 23(2): 98-112 (April 1995) (click here for an on-line copy of that article)].
Farm Meadow is a predominantly level hayfield with one gentle knoll, but it contains a variety of mini-habitats. Bordered by woods and a small marsh, its principal grasses are a typical hayfield mix of orchard grass (Dactylis glomerata) and timothy, with a small amount of Kentucky bluegrass. By mid-June the grass was generally between five and six feet in height, but soon these early grasses started to dry, stiffen, and shrink. As the hayfield quickly lost its uniformity, an understory of alfalfa, clover, and vetch appeared. The wind and the deer then matted the grass, swirled patches in it, and opened lanes through which birds could fly unobserved. Later, some milkweed, dock, and other weed stalks appeared.
I monitored Farm Meadow nearly every day in 1994 from early May until the field was cut. On June 28, 1994, I heard, coming from deep in the hay, a song that I knew I did not know and had not heard in that field before. I had heard, however, a Henslow's Sparrow before--once and long ago--with Allen Morgan in 1945. I had filed its emphatic, tiz-lik repetitive song away in my head. As I tried to identify this new song, I considered the possibility of a Henslow's but dismissed the thought. Although abrupt and raspy, this 1994 Lincoln bird's song had more syllables than the two-beat Henslow's song of my memory, some field guides, and the Peterson bird tape. The song varied in pattern and volume, e.g., tzi tzi chick or tszi tsbzzzi lik [emphasis last syllable] or te-tse t-lik [emphasis last syllable]; also, it was not repetitive--one could wait an hour to hear a single song, then hear between one and six single songs over the next ten minutes, and then nothing until one's patience ran out. [Start page 114.]
In the days to follow, while making other observations from the field edge, I listened for the song and tried with remarkably little success to glimpse the singer. The call came erratically from a six-acre portion of the field, and occasionally the call followed me as I walked slowly around the field. After the farmer-lessee cut most of the hayfield on July 3, the bird continued its infrequent calls from the cut-later Bobolink sanctuary. (On July 7, from the area where the bird was calling, there was a single, very different, strong sparrow song, almost finch-like, which was very puzzling and not heard again. Perhaps this was the Henslow's rarely-heard mating song, which is mentioned in Bent's Life Histories.)
On July 10 I saw in Forbush's Birds of Massachusetts that the Henslow's Sparrow did have a song that resembled the more complex song I was hearing. (Both Bent's Life Histories and the sonogram in Chandler Robbins' field guide suggested the multiple beats that are hidden even in the sparrow's regular song.) That afternoon, the still-invisible sparrow, as if it knew the game were almost up, erupted with thirty-two of its typical tsi-lik songs, every six to ten seconds for four minutes straight. The next morning, energized but still disbelieving, I played Peterson's faint Henslow's tape on a tape recorder, but I got no response. The hidden bird did sing sporadically from afar. I then borrowed a more powerful recorder, and that afternoon a surprised Henslow's Sparrow perched in full view for the first time and challenged my machine with repeated song. I called Boots Garrett to be my witness and held up a camera (with ASA 1600 color print film) to my binoculars and scope for some confirmation photos.
When Wayne Petersen and Simon Perkins of the Massachusetts Audubon Society (MAS) and others arrived the next morning, a second Henslow's Sparrow appeared, delighting us with the possibility of breeding in a field much smaller than the seventy-five-plus acres thought to be optimal for Henslow's Sparrows. The male perched on a weed, threw its head back, and announced its wretched song every six to ten seconds for minutes on end.
At full volume these repeated, emphatic vocalizations were more than once clearly audible at a surprising 270 yards away. The typical song was a quick, thin, dry, run-together, raspy, cricket-like gargle "tsi-lik." [Emphasis last syllable.] I eventually grew quite fond of this effort. The presumed female would periodically appear when the male was perched up and singing, or would fly in tandem with or loosely accompany the male. No counter-singing was heard, and no aggressive behavior between the two birds was seen.
Over a celebration breakfast with Wayne, Simon, Gwyn Loud, and Paul Miliotis, we talked about what was next. Although most had an impulse to keep the event a secret to protect the possibility of breeding, we feared that was unrealistic--it was too rare a bird to be unrevealed for long. Wayne also pointed out that there would rarely be a better opportunity to have controlled access to a quality bird with an environmental message--the hayfield was on handsome [Start page 115] conservation land, away from houses, and only a 200-yard walk from a commuter-rail parking lot. He suggested that the bird should be protected not by secrecy but by education and guidance. We asked Geoff McGeon, the town's conservation administrator, to join us at breakfast. Before the next cup of coffee was done, a strategy was on a napkin--get the cooperation of the farmer-lessee, stop all further cutting, stake a trail through the cut field to an observation area, post the uncut part of the field and most of its periphery, ban further tape playing, touch base with other town officials and the Natural Heritage Program, make educational signs and handouts to distribute at the trail head, schedule the town conservation wardens to be available periodically for education and guidance, and postpone the announcement on the Voice of Audubon until all was in place the following weekend.
Between 600-1000 well-behaved birders and townspeople eventually enjoyed this bird, for the male continued to sing and appear throughout July. If there were to be a "next time," however, I hope the community could be more included and involved. The Commission was concerned that general publicity might attract vandals. I respect that caution but still wonder whether we should have done more to build public support for birding and for conservation--though this bird was not very charismatic.
Late season activity
On July 24, during a forty-minute burst of activity, observers saw the birds making eight or ten flights to a particular spot in the grass an eye-squinting eighty-five yards away. On three of those flights the sparrows carried long stems of grass, probably for nest-building. The second bird (the presumed female) was last seen on July 30, which was, based on the date of observed nest-building, the estimated start of incubation. The male remained near the presumed nest site and sang regularly but often very faintly until August 7. After August 7 there was a gap in visible activity until August 11-15, dates that correspond to the anticipated date of the hatch. Short flights with light objects to and from the nest area were distant, easy to miss, and often did not occur more than once or twice within an hour. After a last report of two distant flights on August 20, which was the anticipated date of fledging, the Henslow's Sparrows dropped out of sight and hearing until the evening of September 6, when I heard two unmistakable songs, five minutes apart, sounding again like the songs of late June.
After that, there were only occasional cryptic hop-flights of possible-probable birds, one report of a stationary bird on September 12 (the first visual identification since August 3), and very faint, possible vocalizations, which were frustratingly indistinguishable from insect noises. Other migrating sparrow species then flooded into the field, and hawks patrolled overhead. The five-acre sanctuary was cut about Columbus Day.
Stephen F. Ells
39 Todd Pond Road
Lincoln, MA 01773
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