Kirtland's warbler (Dendroica kirtlandii) COSEWIC assessment and status report: chapter 4

Distribution

Global range

Kirtland’s Warbler is known to breed in the Lower and Upper Peninsulas of Michigan, Wisconsin and in Ontario.

Distribution in United States

The main Kirtland’s Warbler population occurs in Michigan, with a very small, recently confirmed population also occurring in Wisconsin. The species has bred in 19 counties in the Lower and Upper Peninsulas of Michigan (Mayfield 1992; Figure 1), with the primary nesting location in the Au Sable River drainage. While the main population occurs in the Lower Peninsula, birds have been recorded in the Upper Peninsula since 1982, and are believed to have bred there since 1995. Four singing males were also recorded in 2006 in central Wisconsin, and three nests were discovered in 2007 (K. Grveles, pers. comm. 2007). The Kirtland’s Warbler has been recorded as accidental in a further six states.

Distribution on wintering grounds

The Kirtland’s Warbler is a Neotropical/Nearctic migrant, spending the non-breeding season in the Bahamas, where it is secretive and hard to locate (Mayfield 1992). Kirtland’s Warblers have also been sighted in the Grand Turks and Caicos Islands (Mayfield 1960; Clench 1978) and the Dominican Republic, and there are unconfirmed records from Cuba. In the Bahamas, most sightings have been on islands with open stands of Caribbean pine (Pinus caribaea; Haney et al. 1998).

Distribution in Canada

Two breeding records are known for Canada. The first is from Oro township, Simcoe County (Midhurst, Barrie), Ontario, where two adult birds were seen with a recently fledged young in August 1945 (Speirs 1985). It is not clear, however, whether the young bird was a Kirtland’s Warbler or a Brown-headed Cowbird fledgling. The second record is from Canadian Forces Base (CFB) Petawawa in Ontario, where a nest was discovered in 2007 (Canadian Forces Base Petawawa 2007). Numerous observations of Kirtland’s Warbler made between 1916 and 1978 at CFB Petawawa (Appendix 1), suggest that the species may have also bred there in the past (Harrington 1939; Environment Canada 2006).

According to the Kirtland’s Warbler Recovery Plan, there have been 77 records of Kirtland’s Warbler in Canada, ranging from Minaki, Ontario (76 records from Ontario) in the west to Kazabazua, Québec (one record from Québec) in the east (Environment Canada 2006; Figure 1; Appendix 1). Of the 76 records from Ontario noted in the Recovery Plan, 38 have been accepted by the Ontario Bird Records Committee (OBRC), two records have been rejected and 37 have not been submitted (I. Richards, pers. comm. 2007; Appendix 1), including the 2006 and 2007 observations from CFB Petawawa.

Most observations are of males on spring migration (12 pre-1990, and 16 post-1990), with very few on fall migration (three pre-1990) and even fewer recorded during mid-summer (one pre-1990 and one post-1990). There are 12 records of male Kirtland’s Warblers singing in suitable breeding habitat, suggesting, at the very least, some attempts to breed in those areas (Appendix 1).

The Extent of Occurrence and Area of Occupancy in Canada are unknown.

Figure 1. Kirtland’s Warbler breeding distribution in Wisconsin, Michigan, and Southern Ontario (J. Trick pers. comm. 2007; T. Hogrefe pers. comm. 2007; P. Aird pers. comm. 2007; K. Tuininga pers. comm. 2007).

Figure 1. Kirtland’s Warbler breeding distribution in Wisconsin, Michigan, and Southern Ontario (J. Trick pers. comm. 2007; T. Hogrefe pers. comm. 2007; P. Aird pers. comm. 2007; K. Tuininga pers. comm. 2007).

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