| Abstract: | We monitored radio-tagged Harlequin Ducks (Histrionicus histrionicus) to determine whether nocturnal feeding was part of their foraging strategy during winter in south-central Alaska. Despite attributes of our study site (low ambient temperatures, harsh weather, short day length) and study species (small body size, high daytime foraging rates) that would be expected to favor nocturnal foraging, we found no evidence of nocturnal dive-feeding. Signals from eight radio-tagged Harlequin Ducks never exhibited signal loss due to diving during a total of 780 minutes of nocturnal monitoring. In contrast, the same eight birds exhibited signal loss during 62 ?? 7% (SE) of 5-minute diurnal monitoring periods (total of 365 minutes of monitoring). Our results suggest that Harlequin Ducks in south-central Alaska face a stringent time constraint on daytime foraging during midwinter. Harlequin Ducks wintering at high latitudes, therefore, may be particularly sensitive to factors that increase foraging requirements or decrease foraging efficiency. |
| Genre: | Article |
| ProdID: | 70029421 |
| Citation Author: | Rizzolo, D. J.; Esler, D.; Roby, D. D.; Jarvis, R. L. |
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| Citation End Page: | 177 |
| Citation Issue: | 1 |
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| Citation Language: | English |
| Citation Larger Work Title: | Condor |
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| Citation Number Of Pages: | 5 |
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| Citation Search Results Text: | Do wintering Harlequin Ducks forage nocturnally at high latitudes?; 2005; Article; Journal; Condor; Rizzolo, D. J.; Esler, D.; Roby, D. D.; Jarvis, R. L. |
| Citation Start Page: | 173 |
| Citation Volume: | 107 |
| Citation Year: | 2005 |
| Type: | citation/reference |
| Text: | Do wintering Harlequin Ducks forage nocturnally at high latitudes?; 2005; Article; Journal; Condor; Rizzolo, D. J.; Esler, D.; Roby, D. D.; Jarvis, R. L. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sat, 1 Jan 2005 00:00 -0600 |
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