59 Henslow's Sparrows: An Up-Date by Madeline J.W. Austen Introduction Knapton 119821 reported that only In Canada, Henslow's Sparrow 17 individuals in seven widely (Ammodramus henslowiil has been scattered areas across southern known to breed in Ontario and in Ontario were detected during the southwestern Quebec. In recent 1981 breeding season. In 1983, the years, Henslow's Sparrow has been known Ontario population of known to breed only in Ontario, with Henslow's Sparrows was 25 to 29 the majority of nesting sites in the individuals at 13 sites (Ontario mid-1980s being located in the Breeding Bird Atlas; Risley 19831. southern part of Hastings, Lennox­ During the Atlas of the Breeding Addington, and Frontenac Counties, Birds of Ontario, the Henslow's and in Prince Edward County. It also Sparrow was found in only 38 has occurred in Grey, Bruce, and squares, and in only 8% of these was Dufferin Counties. Figure 1 shows breeding confirmed (Cadman et al. the breeding distribution of 19871. At this time, it was unlikely Henslow's Sparrow in Ontario, based that the total provincial population on data from the Breeding Bird Atlas exceeded 50 pairs in any given year and the Ontario Rare Breeding Bird (Knapton 1987). The ORBBP received Program (ORBBPI. information on only 23 Henslow's This article provides an up-date Sparrow sites, seven of which were on the status of Henslow's Sparrow active during the 1986 to 1991 period. and summarizes the results of survey However, breeding site information efforts since Knapton (19861. from the Kingston area was not reported to the ORBBP. Population trends and status Active colonies reported in in Ontario Ontario Seasonal Summary reports Population declines have been during the summers of 1986 - 1991 reported in Ontario within the last 30 included: Shelburne area (T. Sabol to 40 years, and the species' range and Walpole Island (C. Spitzl in 1986; within the province has also been Shelburne area (T. MurrayI and reduced. Henslow's Sparrow numbers Kortright, Kleinburg (E. Edmundsl in appeared to have decreased in the 1987; three birds in Arkell Hills, late 1970s or early 1980s in Ontario Guelph in 1988; and Conn area in (Knapton 1982; Speirs 19851. Declines Grey COunty (fide T. Murrayl(R. have also been noted in the number Weir pers. corom. 19921. of individual HensloW's Sparrows reported during spring migration in Current Status Ontario from 1986-1993: 17, 17, 18, In 1986, Henslow's Sparrow was 0, 3, 5, 7, and 8 (R. Weir, pers. listed as Threatened by the Ontario corom., 1992; R. Ridout, pers. Ministry of Natural Resources. Based corom., 19931. on the ORBBP's review of available VOLUME 12 NUMBER 2 60 CI) 0c CI) I :2 b w> g' ~ ~ tt '6 , l. Q. et CI) ~ CI) et" o. m~ • Figure 1: 10-km squares in which the Henslow's Sparrow was reported to the Breeding Bird Atlas and the Ontario Rare Breeding Bird Program in southern Ontario. ONTARIO BIRDS AUGUST 1994 61 information on the population trends Lennox-Addington, Leeds-Grenville, and status of Henslow's Sparrow in and Stormont-Dundas-Glengarry Ontario and across North America, Counties. Eighteen former Henslow's the Committee on the Status of Sparrow sites were visited in 1992, Endangered Wildlife in Canada but no Henslow's Sparrows were lCOSEWIC) designated the Henslow's located. Only three sites lTuttles Hill, Sparrow as Endangered in Canada in Frontenac Co.; Arkell Hill, April, 1993. The species was formally Wellington Co.; and a site west of registered under the Ontario Dundalk, Grey Co.l still had habitat Endangered Species Act in May of that was apparently suitable for the 1994 to give the species and its species. Approximately 150 other habitat legal protection. sites with suitable habitat or potentially suitable habitat were Recent surveys in Ontario checked for Henslow's Sparrows in A thorough survey for Henslow's 1992. One singing male was found in Sparrows had not been conducted in eastern Ontario on June 25 and 26, core breeding areas in Ontario since well into the breeding season. The Knapton 119861. In June of 1988, bird was found in an old hayfield, 1989 and 1990, ORBBP staff and approximately 3 ha in size, that is volunteers surveyed the southern dominated by grasses (0.5 - 1 min portion of Grey County and sections heightL but is beginning to be of Dufferin County for Henslow's invaded by shrubs. Sparrows; two birds were found in In 1993, suitable sites were 1988, one singing male was found in checked for Henslow's Sparrows in 1989, and no birds were found in Prince Edward County, Amherst 1990. Volunteers also surveyed north Island, and Walpole Island by Ridout Wellington for Henslow's Sparrows and Austen (19931. Some historic sites during the ORBBP but no birds were and suitable areas in Haldimand­ located. In 1989, a site with 10 Norfolk and Niagara Regional territories was located in Haldimand­ Municipalities were surveyed by Norfolk Regional Municipality, but volunteers. Two sites near Sarnia the colony was "abandoned lLambton CountYl were also checked mysteriously" during the breeding for Henslow's Sparrows: the Bunyan season lD. McRae, pers. comm.l. location where a pair was present in In 1992 and 1993, surveys for 1984 (Knapton 1984, 1986), and the Henslow's Sparrows were conducted Sarnia Airport where a singing male in various areas of southern and was reported in 1985. In 1993, eastern Ontario using census Henslow's Sparrows were found only techniques similar to Risley (1983) at the site located in eastern Ontario and Knapton (19861. In the summer during the 1992 survey. of 1992, thirty lO-km squares in The results of the 1992 and 1993 which the species occurred during surveys suggest that far fewer than 50 the Atlas were surveyed. Squares pairs (probably less than 10 pairsl are were located in Grey, Wellington, breeding in the province. It is Dufferin, Northumberland, Prince possible that there are other active Edward, Hastings, Frontenac, Henslow's Sparrow sites that remain VOLUME 12 NUMBER 2 62 undetected, but surveys by Risley Sparrow populations from 1966 to (1983), Knapton (1986), Austen and 1988, with an average rate of decline Kubisz (1992), and Ridout and Austen of 3.5 to 4.5% per year. Results from (1993) all suggest that the Ontario BBS routes in Canada during the population of Henslow's Sparrow is period from 1967 to 1988 suggest a continuing to decline. Clearly, decline in Henslow's Sparrow Henslow's Sparrows are critically numbers, but the species was not imperilled in Ontario and worthy of reported on enough routes to Endangered status. accurately determine a population trend (B. Peterjohn, pers. comm., 1991). The BBS is a roadside survey, Henslow's Sparrow sightings conducted annually in mid-June in A Henslow's Sparrow sighting was road-accessible areas across North reported to Birders Journal in the America. summer of 1992 (location unknown, Henshaw and Kerr 1992), but In the majority of the according to the reporter the site was northeastern and northcentral United abandoned early in the summer. A States where Henslow's Sparrow has Henslow's Sparrow was also reported been listed, the species is considered singing at one of the first ten stops on of Special Concern or Endangered. It the Roblin Breeding Bird Survey is listed as Endangered in route in the Tweed area ou 7 June Massachusetts, New Hampshire, New 1992 (E. Hayakawa, pers. comm., Jersey, Vermont, and Virginia 1992). Ron Weir (pers. comm.) (proposed); Threatened in estimated that there were about six Connecticut, Illinois, Indiana, and active Henslow's Sparrow sites in the Iowa; of Special Concern in Kingston area in 1992: two sites in Kentucky, Minnesota, New York, each of Prince Edv'lard, Lennox­ Maryland, West Virginia, and Addington, and Frontenac counties. Wisconsin; and At Risk in However, no birds were found by Pennsylvania (Hands et al. 1989; ORBBP staff in the Kingston area in Smith 1992). Henslow's Sparrow has 1992, but these surveys were been listed as a "migratory nongame restricted to fields near roadsides. bird of management concern" in the north-central region which includes In 1993, Henslow's Sparrows Illinois, Indiana, Iowa, Michigan, were reported during spring Minnesota, Missouri, Ohio, and migration at Long Point, Point Pelee, Amherst Island, Hockley Valley near Wisconsin (United States Fish and Orangeville (unconfirmed) and Wildlife Service 1987). Butcher (1989) Unionville, but were not known to labelled Henslow's Sparrow as one of breed in these areas. two species of management concern in the United States that are in the Population trends in North most danger of extinction. America and adjacent states Breeding Bird Atlas data from the Breeding Bird Survey (BBS) results northeastern and northcentral United from North America, eastern North States also confirm that Henslow's America, and the United States show Sparrow is a rare breeding bird. Ohio significant declines in Henslow's is the only state listed that has ONTARIO BIRDS AUGUST 1994 63 Henslow's Sparrows breeding in more Recovery Efforts than 10% of the atlas blocks Although numbers of Henslow's surveyed, with birds reported in Sparrows in Ontario are very low at 18.5% of blocks surveyed. present, there is still potential for the species to recover in the province. There are several active colonies Reasons for decline nearby in Michigan and New York Declines of Henslow's Sparrows in that may act as source populations, the Northcentral and Midwest United and the species is still being seen in States appear to track loss of spring migration at sites such as Long grassland or old field habitats on the Point and Point Pelee.