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RESPONDENT
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Joseph Liebezeit
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SITE NAME
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Prudhoe Bay Oilfield, USA
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| Contact details
(phone/fax//e-mail//address): |
| 503-241-7231/503-241-7925(fax) // jliebezeit@wcs.org // Wildlife Conservation Society, North America Program - Pacific West office, 718 SW Alder Street, Suite 210, Portland, OR 97205, USA
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PROJECT DETAILS |
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Project name:
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Nest survival of tundra-nesting birds and human development on the North Slope of Alaska
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Start of survey:
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End
of survey: |
Team
size: |
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3.06
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25.07
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4
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WEATHER
CONDITIONS
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| Season phenology: |
average
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Weather conditions: |
The Kuparuk River ice break-up occurred approximately May 30th (just before our arrival to the site). Snow reduced to 50% approximately on 2 June (assuming that snow melt occurred consistently across time). Our snow cover surveys indicate that snow cover in the flat areas was about 35% on 6 June. It appeared that the study plots closest to the Beaufort Sea had the deepest snow and highest snow cover. At this site, our study plots range 2-13 km inland from the coastline. Days were consistently warmer than in 2003 for much of the season. There also were more sunny days in 2004 (compared to 2003) and there were no heavy rain or snow storms during our time in the field.
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| Date of 50%
snow-cover: |
2.06
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| Date of ice-break on
rivers: |
30.05
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| Date of final loss of
snow: |
18.06
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
low
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Breeding conditions:
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We discovered and monitored all nests on (or near) 24 10-hectare study plots every 3-6 days until nesting fate was determined. We discovered 191 nests of 20 species from 10 June to 16 July. Of the 191 nests, 61 were discovered off-plot. One hundred nineteen nests successfully hatched/fledged and 59 failed. We were unable to reliably assess the fate of 12 nests. Nest predation was the most important cause of nest failure (55 of 59 nest failures, 93%). Other sources of nest failure were abandonment (n = 3) and trampling (n = 1). Trampling was most likely due to caribou. Mayfield estimates of nesting success for the four most common species were: Semipalmated Sandpiper (n=35): 0.684, Lapland Bunting (n=31): 0.364, Pectoral Sandpiper (n=17): 0.431, and Red Phalarope (n=10): 0.695.
We conducted three 10-minute point count surveys for potential nest predators on all plots. We conducted 3 replicates of this survey on all plots during the course of the season. A total of 10 potential predators were detected (n = # of detections): Glaucous Gull (n = 148), Arctic Skua (n = 72), Common Raven (n = 14), Long-tailed Skua (n = 12), Arctic Fox (n = 7), Unidentified Skua (n = 5), Pomarine Skua (n = 4), Short-eared Owl (n = 2), Unidentified Raptor (n = 2), Peregrine Falcon (n = 2), Red Fox (n = 2), and Snowy Owl (n = 2). The most common potential predators were Glaucous Gull and Arctic Skuas.
We expanded our effort at this site in 2004 by adding 12 new 10-ha plots covering a larger geographic area to the east and west. Overall, we found more nests this season than last season because of the expanded work effort, however, proportionally fewer nests were found. This is reflected in the lower overall nest density in 2004 compared to 2003 (52.9 nests/km2 vs. 68.3 nests/km2). More nests were successful in 2004 compared to 2003 (62% vs. 48%).
We did notice more Short-eared Owls earlier in the season (first week or two of June) compared to previous years. However, by mid-June observations of Short-eared Owls were only occasional.
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Rodent dynamics:
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Lemming numbers were low based on our field observations though we did no trapping. However, proportionally, more lemmings were seen at this site than in 2003. A total of about 15 lemmings were seen (5 seen in 2003). Only 3 of those were actually observed on surveys.
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Rodent species recorded:
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Summary
of fauna studies: |
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