| Abstract: | The Yellow-billed Loon (Gavia adamsii) is of conservation concern due to its restricted range, small population size, specific habitat requirements, and perceived threats to its breeding and wintering habitat. Within the U.S., this species breeds almost entirely within the National Petroleum Reserve-Alaska, nearly all of which is open, or proposed to be opened, for oil development. Rigorous estimates of Yellow-billed Loon population size and trend are lacking but essential for informed conservation. We used two annual aerial waterfowl surveys, conducted 1986a??2003 and 1992a??2003, to estimate population size and trend on northern Alaskan breeding grounds. In estimating population trend, we used mixed-effects regression models to reduce bias and sampling error associated with improvement in observer skill and annual effects of spring phenology. The estimated population trend on Alaskan breeding grounds since 1986 was near 0 with an estimated annual change of a??0.9% (95% CI of a??3.6% to +1.8%). The estimated population size, averaged over the past 12 years and adjusted by a correction factor based on an intensive, lake-circling, aerial survey method, was 2221 individuals (95% CI of 1206a??3235) in early June and 3369 individuals (95% CI of 1910a??4828) in late June. Based on estimates from other studies of the proportion of loons nesting in a given year, it is likely that <1000 nesting pairs inhabit northern Alaska in most years. The highest concentration of Yellow-billed Loons occurred between the Meade and Ikpikpuk Rivers; and across all of northern Alaska, 53% of recorded sightings occurred within 12% of the area. |
| Genre: | Article |
| ProdID: | 1016362 |
| Citation Author: | Earnst, Susan L.; Stehn, R. A.; Platte, Robert; Larned, W. W.; Mallek, E. J. |
| Citation Contributing Office: | Forest and Rangeland Ecosystem Science Center |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 304 |
| Citation Issue: | |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Condor |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 16 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | p. 289-304 |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Population size and trend of Yellow-billed Loons in northern Alaska; 2005; Article; Journal; Condor; Earnst, Susan L.; Stehn, R. A.; Platte, Robert; Larned, W. W.; Mallek, E. J. |
| Citation Start Page: | 289 |
| Citation Volume: | 107 |
| Citation Year: | 2005 |
| Type: | citation/reference |
| Text: | Population size and trend of Yellow-billed Loons in northern Alaska; 2005; Article; Journal; Condor; Earnst, Susan L.; Stehn, R. A.; Platte, Robert; Larned, W. W.; Mallek, E. J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sat, 1 Jan 2005 00:00 -0600 |
| Publisher: | |
