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Breeding pair surveys for Harlequin Duck were done on 409 km of 20 streams during May and June, 1993; a total of 42 Harlequins (27 males and 15 females) were seen on 6 streams. Brood surveys were done on 377 km of 21 streams during July and August, 1993; a total of 78 Harlequins (19 females, 59 young in 21 broods) were seen on 9 streams. Harlequins were reported on 4 additional streams. Reproductive success, on streams surveyed both for pairs and broods, averaged 0.40 broods per female. Success in the North Fork Flathead drainage was substantially lower (0.32 broods per female) than in the lower Clark Fork drainage (0.60 broods per female). Brood size at or near fledging (Class III) was 2.86; August brood sizes were consistent among all drainages. No new breeding streams were confirmed in 1993. No birds were seen during pair (May) or brood (August) surveys on Sullivan Creek, which had Harlequins in 1992. We continued banding Harlequin Ducks in the Flathead and Clark Fork drainages. Sixty-eight Harlequins (13 adult males, 14 adult females, and 41 juveniles) were marked on 7 streams. This brings the total number of Harlequin Ducks banded since 1991 to 159 (22 adult males, 34 adult females, and 103 juveniles). We observed 20 previously marked birds on streams. The banding program, while small in scale for waterfowl, is providing a significant tool for local monitoring and identifying coastal areas where Montana breeding birds molt and winter. Six movements detected in 1993 were interesting. A male marked on McDonald Creek, Glacier National Park, on 6 May 1993, was captured on Hornby Island, along the southeast coast of Vancouver Island, British Columbia on 5 August 1993. This was the first record of a bird marked in Montana being relocated on the coast. On 14-15 March 1994 three Harlequins were observed on Hornby Island, all marked as juveniles in 1992-3 on McDonald Creek. Local movements of birds, heretofore undocumented, include two marked females found on different streams in 1993 than where they were originally marked in 1992. Stream mouths were separated by 6 and 17 km respectively, across a reservoir and lake.