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SITE NAME
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Jago River, Arctic National Wildlife Refuge, USA
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| Contact details
(phone/fax//e-mail//address): |
| (907) 786-3423 // jim_a_johnson@fws.gov // USFWS/MBM, 1011 E. Tudor Road, MS 201, Anchorage, AK 99593 USA
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PROJECT DETAILS |
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Project name:
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Distribution and abundance of breeding shorebirds on the coastal plain of the Arctic National Wildlife Refuge
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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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7.07
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8
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WEATHER
CONDITIONS
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Weather conditions: |
| Upon our arrival in late-May, 90% of the study area was covered by snow. On 9 June 50% of flat areas was snow free and the final loss of snow cover occurred on 15 June. Weather 1 June - 14 June was considered normal. Majority of this period was windy with temperatures below 0øC. No major precipitation events during this period. Air temperature rose steeply during mid June, reaching an average of 12øC for the remainder of our stay. Weather was unusually mild 15 June - 7 July with average temperatures 10-18øC. Several days during this period were extremely warm, ~35øC. Smoke from large fires to the south blanketed the study area for several days in late June and early July. There were no major snow events and only one major rain event on 6 July, which caused minor flooding of the Jago River.
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| Season temperature: |
average
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| Date of 50%
snow-cover: |
8-10.06
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| Date of ice-break on
rivers: |
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| Date of final loss of
snow: |
14-15.06
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
low
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Breeding conditions:
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As a result of the close proximity of two active dens <3 km from our camp, Arctic Fox were seen or heard daily throughout our stay. Caribou, primarily cows and calves, were observed (range = 1 - 125 / day) daily until 27 June. In addition, we observed a single wolf on 21 June, a moose cow and calf on 28 June, a bull moose on 29 June, and single grizzly bears in early June. Because this was our first visit to this site, we are unable to comment on inter-annual differences in bird abundance or reproductive success.
Among avian predators, only Long-tailed and Arctic skuas and Glaucous Gull were common and several nests were located near our basecamp. Pomarine Skua and Short-eared Owl were observed daily until 13 June, after which they were no longer observed. Rough-legged Buzzard, Hen Harrier, and Common Raven were seen infrequently throughout our stay. We observed Bald Eagle, Merlin, and Peregrine Falcon on single occasions during the last week of June and first week of July. We recorded a total of 44 bird species representing 9 orders and 14 families. Of the 12 waders recorded, the most common were Pectoral Sandpiper, Red-necked Phalarope, Semipalmated Sandpiper, Stilt Sandpiper, and American Golden Plover.
One component of our study focused on locating and monitoring nests of all waders occurring within 7, 16 ha plots (1 in riparian habitat, 2 in flooded, 3 in very wet, and 1 in upland) within 5 km of our camp. We found 24 nests of five species. Clutches were initiated first by Semipalmated Plover (6 June), followed by Long-billed Dowitcher (10 June), Pectoral Sandpiper (mean = 11 June), Red-necked Phalarope (mean = 14 June), and Semipalmated Sandpiper (mean = 16 June).
We found between zero (plot predominately tussock tundra) and 8 (plot predominately low centered polygons) (mean = 3.3) nests per plot. Hatching success was 100% for Semipalmated Plover (n=1), Semipalmated Sandpiper (n=2), and Long-billed Dowitcher (n=1), 80% for Red-necked Phalarope (n=10), and 50% for Pectoral Sandpiper (n=10). Nest failure was primarily attributed to predation by Long-tailed and Arctic Skuas (we observed a Long-tailed Skua depredate an American Golden-Plover nest). Additionally, a single complete Buff-breasted Sandpiper nest located outside of our plots, was probably abandoned as a result of human disturbance.
Low predation pressure on shorebirds could be explained by very low densities of the latter in the study area. Predators may have focused more on waterfowl as a reliable or energy efficient food source.
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Rodent dynamics:
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| We did not capture rodents, but consider their numbers to be low this season. This estimate is supported by few observations of Tundra Vole, Greenland Collared Lemming, and Brown Lemmings (single animal seen of each species) combined with the scarcity of signs including tunnels, winter nests, droppings, and clippings near burrows. No apparent trend in numbers was observed.
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Rodent species recorded:
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| Latin | Abundance |
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| Lemmus trimucronatus | rare |
| Dicrostonyx groenlandicus | rare |
| Microtus oeconomus | rare |
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Summary
of fauna studies: |
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