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RESPONDENT
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Joseph Liebezeit
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SITE NAME
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Teshekpuk Lake - Olak, Alaska, 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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Breeding bird diversity, density, nesting success and nest predators in the Olak region of the Teshekpuk Lake Special Area
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Start of survey:
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End
of survey: |
Team
size: |
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5.06
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17.07
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4
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WEATHER
CONDITIONS
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Weather conditions: |
| This years' early season (20 May to 30 June) average air temperatures were similar to 2005 (within ~0.5°C) but was noticeably colder than in 2006 (by ~3.5°C). Despite the colder temperatures, snow melt was complete approximately 1 day earlier than in 2006. We believe snow depth at the site was lower this year so, despite colder temperatures, snow melt occurred earlier because less snow covered the ground. Very little snow was present (on flat areas) when we arrived at the site on 5 June (<10%). Snow melt was complete approximately four days later in 2005 (16 June) and two days later in 2006 compared to 2007. The stream next to our camp broke prior to our arrival at the site on 5 June (at least a few days earlier than in the 2 previous years). This year was relatively dry with little precipitation. Water levels in all water bodies (rivers, creeks, ponds, etc.) were lower than usual and this was particularly noticeable as the season progressed. There were no major snow storms during the field season. The first mosquitoes emerged on 21 June, about 10 days earlier than in 2005 and 1 day earlier than in 2006.
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| Date of ice-break on
rivers: |
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| Date of final loss of
snow: |
8.06
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BIOTIC
CONDITIONS
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| Rodents abundance evaluation: |
low
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Breeding conditions:
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In accordance with low lemming abundance, Pomarine Skua numbers were also much lower than in 2006 and were not seen at the site after 11 June. We found no evidence that they or Snowy Owls (both species were rare) nested at this site this year. We conducted point count surveys for potential nest predators on each plot at eight different times during the course of the season. A total of eight species of potential nest predators were detected (n= number of detections): the Parasitic (n=70) and Long-tailed (n=31) skuas, Glaucous Gull (n=38), Arctic Fox (n=17), Arctic Ground Squirrel (n=12), Peregrine Falcon (n=3), Red Fox (n=2), lemming (n=2). Arctic Foxes were common and denning.
Overall nest densities were noticeably lower this year than in 2006 (100.1 vs. 132.4 nests/km2). In particular, Pectoral Sandpiper and Red Phalarope nest densities declined significantly from 2006 (20.0 to 9.4 nests/km2 and 15.0 to 7.5 nests km2, respectively). Willow Grouse were numerous and Rock Ptarmigans were common this year in the area.
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Rodent dynamics:
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| We did not capture lemmings but we conducted incidental surveys for lemmings (i.e. tallied lemmings the entire time we were on our study plots on predator count days). We detected 26 lemmings (Brown and Greenland) this year compared to 7 seen in 2005 and 159 seen in 2006. Thus, in 2007 lemming abundance returned to low levels from the high observed in 2006 (from 0.33 to 0.03 lemmings encountered per 30 minutes).
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Rodent species recorded:
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Summary
of fauna studies: |
| We discovered and monitored all nests on (or near) 16 10-ha study plots every 2-6 days until nest fate was determined. We discovered and monitored 191 nests (23 of these were discovered off plot) of 16 species from 11 June to 16 July. One hundred nests successfully hatched/fledged, 70 failed and 21 nests were of unknown fate. Nest predation was the most important cause of nest failure (90%). Other sources of nest failure included abandonment (n=4) and predation due to observers (n=3). Mayfield estimates of nesting success for the 4 most common species were: 0.568 for Lapland Bunting (n=67), 0.646 for Pectoral Sandpiper (n=15), 0.504 for Grey Phalarope (n=13), and 0.707 for Semipalmated Sandpiper (n=18). Nesting success was lower at this site compared to 2006 but was still relatively high with most species having Mayfield nesting success estimates greater than 50%.
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