Harlequin duck monitoring in the Northern East Slopes of Alberta : 1998-2000 preliminary results /

Abstract

Aerial surveys for harlequin ducks {Histrionicus histrionicus ) were conducted in the spring of 1998-2000 in the McLeod and Cardinal River watersheds, and in 10 watersheds in the Willmore Wilderness Park. Ground and aerial surveys of broods occurred in August and September 2000, respectively along the Sulphur and Berland Rivers. The objectives of the surveys were 1) to assess the utility of aerial surveys in censusing harlequin duck populations, and 2) to determine presence, relative abundance, population trends, distribution, and productivity of harlequin ducks in selected watersheds. Visibility from the air was approximately^70% that from the ground during spring surveys of the McLeod watershed in 1998 and 2000 compared with only 13-27% in 1999 when lighting conditions were poor.These results indicate that aerial surveys can be an effective method of censusing harlequin ducks when lighting conditions are favourable. Spring numbers were relatively high in the McLeod-Whitehorse, Berland, and Sulphur watersheds (approximately > 40 birds) followed by the Muskeg, Sheep-Cote, Muddywater-Fetherstonhaugh, and Jackpine watersheds (approximately > 15 birds). Relatively few birds were observed on the Smoky, Cardinal, Little Berland, Wildhay Rivers, and Hardscrabble Creek (< 15 birds). When watersheds were flown in more than one year, the number and distribution of birds were consistent across years for all watersheds except the Muskeg River in which 15 mere birds were seen in 1998 (23) than in 2000 (8). During ground surveys in August 2000, two broods with 5 young each were observed on the West and South Sulphur Rivers. Four broods (three with 7 young, one with four young) were recorded on the South and North Berland Rivers. During aerial surveys in September 2000, four broods (all with 4 young) were observed cm the Sulphur River and five broods (total of 22 young) were observed on the Berland Rivers. Unlike ground surveys, aerial surveys included the mainstems of these rivers. Based on aerial survey results, 18% of females observed in the spring produced broods on the Sulphur River compared with 23% on the Berland River. Female reproductive output (number of ducklings per number of females observed in spring) was 0.73 and 1.00 for the Sulphur and Berland watersheds, respectively. Productivity in these watersheds was, on average, lower than that reported for the McLeod-Whitehorse watershed and the Kananaskis and Elbow Rivers in Kananaskis Country, but was higher than on the Bow River in Banff National Park.

Proposed monitoring plan for harlequin ducks in the Bow Region of Alberta /

“…Six years of intensive research on the Elbow River (1995River ( -2000, and three years on the Kananaskis River (1998)(1999)(2000), provides a good baseline of data and a valid starting point from which to monitor the status of the harlequin duck population in those two watersheds. Based on our current level of knowledge, the Kananaskis and Elbow rivers are considered to be provincially important breeding streams for harlequin ducks in Alberta (P. Gregoire, pers. comm., Kneteman & Hubbs 2000). (MacCallum and Godsalve 2000) and the Bow River in Banff National Park, at 153 ± 25 for (Smith 2000b.…”

“…Data obtained on parameters such as survival rate and productivity from these two streams is considered to be representative of ducks on other streams, although Kneteman and Hubbs (2000) suggest the possibility that changes in population size (and by inference other parameters) might be evident first in small tributaries of lower quality habitat rather than in the larger higher quality rivers. But the smaller numbers of birds found in the smaller tributaries would make it very difficult to obtain some of the same data as in the larger rivers.…”

“…al. 1999, Kneteman andHubbs 2000). These studies determined that aerial surveys are an effective method of censusing harlequin ducks, particularly in remote areas.…”

“…5.3 Analysis of Using Helicopter Surveys to Count Harlequin Ducks As aerial surveys to count harlequin ducks have not been conducted in Kananaskis Country the results of surveys in the McLeod River watershed 1998-2000 (Kneteman and Hubbs 2000) were used to analyze the efficacy of the technique. To estimate visibility of harlequin ducks, aerial surveys were conducted on one of the same days as ground surveys, which took 2-3 days.…”

“…From the work of Kneteman and Hubbs (2000) it appears that aerial surveys have some utility for comparing counts among years but not in calculating a population estimate. The next step is to analyze the power of the aerial surveys to detect decreasing or increasing trends.…”