Table 1. Summary of harlequin ducks marked in 1995, not including birds marked in previous 

 years and recaptured in 1995 (total ducks captured in all years including 1995 are in 

 parentetheses). 



Location Male Female Juv. Total 



DTSTRTBTJTTON 



NORTH AMERICA 



Breeding range. The Harlequin Duck breeds in two disjunct regions in North America 

 (Fig. 2). The Pacific population breeds from western Alaska, northern Yukon, northern British 

 Columbia, and southern Alberta south to Oregon, Idaho, Wyoming, and east of the Continental 

 Divide in Montana. The Atlantic population breeds from Baffin Island (at least formerly) 

 through central and eastern Quebec, eastern Labrador, and northern Newfoundland. Occurs in 

 summer in Mackenzie Valley and near Great Slave Lake, Northwest Territories (American 

 Ornithologists Union 1983, Harlequin Duck Working Group 1993, 1994). 



In the Rocky Mountains of the United States, Harlequins currently breed in western 

 Montana (Reichel and Center 1995), northern and southeastern Idaho (Cassirer and Groves 

 1994), and northwestern Wyoming (Wallen 1993, McEneaney 1994) (Fig. 3). While much of 

 Montana and Idaho has been surveyed (Fig. 1), some areas with potential habitat have yet to be 

 completed; surveying in Wyoming is less complete. As of 1995, surveys have been conducted 

 on approximately 5,640 km of streams (Montana - 2,963 km; Idaho - 1,886 km; Wyoming 792 

 km) (Cassirer et al. 1996). 



In the literature and in unpublished reports. Harlequins within a geographical area often 

 noted as "breeding on XX number of streams." This has been used differently by various authors 

 to mean: 1) every named stream; 2) larger named streams; or 3) the major stream in an occupied 

 drainage. Not all streams used by harlequin ducks during the breeding season are used for 

 nesting or brood-rearing. Some streams where adult harlequins are observed may be used only 

 during migration to and from breeding areas. In order to classify harlequin duck observations in 

 a consistent manner, definitions have been proposed by Cassirer et al. (1996), the first two of 

 which would be considered "Element Occurrences" (EOs) by Natural Heritage 

 Programs/Conservation Data Centers throughout North America. 



