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RESPONDENT
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Robert Gill, Jr.
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SITE NAME
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Gates of the Arctic National Park and Preserve, Alaska, USA
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| Contact details
(phone/fax//e-mail//address): |
| 907-786-3514/907-786-3636(fax) // robert_gill@usgs.gov // U. S. Geological Survey, Alaska Science Center, 1011 East Tudor Road, Anchorage, AK, 99503, USA
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PROJECT DETAILS |
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Start of survey:
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End
of survey: |
Team
size: |
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26.05
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10.06
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WEATHER
CONDITIONS
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Weather conditions: |
| Over this vast area (34,000 km2) spring appeared to be similar to that experienced the previous two years when work was conducted in the western portion of the Brooks Range (see Arctic Birds 4 & 5). At Anaktuvuk Pass, on the north side of the Range, the mean daily minimum and maximum temperatures during the survey period were +2.2øC ñ 2.6 SD (-1.1-+6.1) and +12.7øC ñ 4.0 SD (+3.9-17.8), respectively. Conditions, however, changed markedly during the two-week effort, going from freezing evening temperatures, mostly snow-covered frozen ground, and ice-covered drainages during the first week, to open, rapidly flowing creeks, warm temperatures, and little snow cover at lower elevations during the second week of June. At the end of the period, snow remained at lower elevation only on north-facing slopes but persisted throughout most areas above 1000 m.
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| Date of ice-break on
rivers: |
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| Date of final loss of
snow: |
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
average
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Breeding conditions:
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Plots ranged in elevation between 200 and 1400 m (above sea level) and by dominant habitat from mostly forested to patchy alpine tundra and bare ground. In 2003, we recorded a total of 96 species of birds, considerably more than recorded the previous two years elsewhere in the Brooks Range, but the frequency at which we sighted shorebirds was the lowest among the parks, with shorebirds recorded on only 31% of the counts. The most frequently seen shorebirds were American Golden-Plover, Wilson's Snipe, Wandering Tattler, Lesser Yellowlegs, and Red-necked Phalarope. Potential shorebird predators recorded on plots (in decreasing order of occurrence) included Common Raven, Common Gull, and Long-tailed Skua. No Parasitic or Pomarine skuas were recorded on actual point counts, but the occasional bird was noted between points. No Snowy Owls and only two Short-eared Owls were detected by crews in 2003.
Neither avian or mammalian predators appeared in numbers that would seemingly have affected bird reproduction in 2003. For example, skuas of any kind were recorded on only 10/27 (37%) of the plots. Long-tailed Skuas were the most common, being seen on all ten plots on which skuas were recorded. Besides the Long-tailed Skuas, we recorded a single Pomarine Skua and 1-5 Parasitic Skuas on another plot.
We had potential mammalian predators on 19 of the 27 plots (70%). Arctic Ground Squirrels were recorded on 13 plots (48%), Wolf on 12 plots (44%), and Red Fox on 4 plots (15%). We also had Red Squirrels on 4 plots (15%), Wolverine on 2 plots, and a Least Weasel on one plot. Brown Bears were recorded on 89% of the plots.
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Rodent dynamics:
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| During 2003 we made a special effort to assess the levels of lemmings and voles through subjective measures of such things as the extent of runways and winter nests, extent of burrows, amount of droppings, and sightings of live animals. Collectively, these signs pointed to relatively low to moderate levels of microtine rodent populations throughout the area. Among the 27 plots, no or low numbers were detected on 10 (37%) plots, moderate numbers on 10 (37%) plots, and high numbers on 6 (22%) plots. Little else can be said because not all crews distinguished between signs of lemmings and voles.
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Rodent species recorded:
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Summary
of fauna studies: |
| Between 26 May and 10 June 2003, the Alaska Science Center of USGS deployed five, two-person teams of biologists throughout Gates of the Arctic National Park and Preserve in the central Brooks Range of northern Alaska as part of a continuing assessment of the montane-nesting avifauna of the region. During the 2003 effort, biologists visited 27, 100-km2 randomly selected plots, on which they spent an average of 48 h each plot. Among all plots, they sampled a total of 646 points during 108 h of total observation time.
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