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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 success and nest predators of tundra-nesting birds in the Prudhoe Bay Oilfield - Long-term monitoring
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Start of survey:
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End
of survey: |
Team
size: |
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1.06
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20.07
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2
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WEATHER
CONDITIONS
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Weather conditions: |
Our snow cover surveys indicate that snow cover in the flat areas was about 20% on 4 June, and it completely melted on approximately 13 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 2005 for much of the season (especially June). There were no major snow storms during our time in the field.
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| Date of ice-break on
rivers: |
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| Date of final loss of
snow: |
13.06
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
average
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Breeding conditions:
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| We sampled at the same plots we sampled in 2005 (12 10-ha plots). Nest densities were the highest at this site in the 4 years since monitoring began in 2003 (101.6 nests/km2; the previous high being 75.8 nests/km2 in 2005). Nest success for 2 of the 3 most common nesters (Pectoral Sandpiper and Lapland Longspur) was noticeably higher in 2006 versus 2005. Pomarine Jaegers were also observed more frequently this season.
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Rodent dynamics:
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| Lemmings were commonly observed and seen in the highest numbers since 2003 based on our field observations though we did no trapping. We observed 19 lemmings in 2006 during incidental predator surveys versus 3 in 2005. Two lemmings were observed during timed surveys.
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Rodent species recorded:
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Summary
of fauna studies: |
We discovered and monitored all nests on (or near) 12 10-hectare study plots. Nests were monitored every 3-6 days until nesting fate was determined. We discovered 157 nests of 16 species from 9 June to 20 July. Of the 157 nests, 32 were discovered off-plot. Ninety-five nests successfully hatched/fledged and 47 failed. We were unable to reliably assess the fate of 15 nests. Nest predation was the most important cause of nest failure (43 of 47 nest failures, 91%). Other sources of nest failure were abandonment (n = 2) and predation due to observers (n = 2). Mayfield estimates of nesting success for the three most common species were: Semipalmated Sandpiper (n=26): 0.758, Lapland Longspur (n=24): 0.659, Pectoral Sandpiper (n=19): 0.705 and Red-necked Phalarope (n=13): 0.771.
We conducted three 10-minute point count surveys for potential nest predators on each plot at three different times (three replicates) during the course of the season. A total of eight potential predators were detected (n= # of detections): Glaucous Gull (n = 44), Parasitic Jaeger (n = 25), Pomarine Jaeger (n = 6), arctic fox (n = 6), Long-tailed Jaeger (n = 2), red fox (n = 2), lemming sp. (n = 2), and Northern Harrier (n = 2).
We also conducted incidental surveys for lemmings (i.e. tallied lemmings the entire time we were on our study plots on predator count days). We detected 19 lemmings (brown and collared) this year compared to 3 seen in 2005.
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