| 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 |