U.S. Geological Survey Home Page USGS Patuxent Wildlife Research Center Science Meetings; dedicated to Chandler S. Robbins USGS Patuxent Wildlife Research Center; Science Meetings dedicated to Chandler S. Robbins Dedicated to Chan Robbins USGS Patuxent Wildlife Research Center; Science Meetings dedicated to Chandler S. Robbins Poster Abstracts from USGS Patuxent Wildlife Research Science Meetings, October, 2006
Patuxent Science Meeting 2006 Poster Abstract

Population demographics and breeding ecology of the Long-tailed Duck

(Clangula hyemalis) in the Churchill, Manitoba area

Perry MC, Alison RM

The population demographics and breeding ecology of long-tailed ducks (LTDUs; Clangula

hyemalis) are being studied in the Churchill, Manitoba area and data are being compared to

data collected 30 years ago. This area is unique in that there are numerous nesting ducks, is

readily accessible to researchers, and represents the most southern known breeding population

of long-tailed ducks. LTDUs on the study site were captured during a two-week period in mid-

June 2005 and 2006 with mist nets set over water. In addition, some females were captured

with the use of a long-handled dip net while incubating eggs. Some females used the same

nest for two consecutive years as indicated by the presence of year-old embryo sacs among

the un-hatched eggs. A total of 82 LTDUs were banded and sex ratio was equal among after

hatching year adults and hatching year young. However, no second year males were captured

in June, although second year females were common on breeding site. During June 2005 and

2006, a total of 27 nests were discovered and mean clutch size was 7 eggs. Several nest

starts (1-2 eggs) were discovered, but eggs disappeared within a few days apparently from

herring gull (Larus argentatus) predation. This study revealed the close association of LTDUs

and common eiders (Somateria mollissima) and arctic terns (Sterna paradisaea), which nest

simultaneously and in the same habitat. Both species seem to benefit LTDUs by reducing

predation by herring gulls, whose numbers are increasing in the study area. The use of islands

or narrow peninsulas as nesting sites for ducks and terns was an important characteristic of

nesting sites that might have potential benefits from reduced predation. Understanding the

Churchill population of LTDUs could have important implications in understanding populations in

Friday, September 22, 2006



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