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RESPONDENT
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Robert Rockwell
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SITE NAME
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Wapusk National Park, the La Perouse Bay, Canada
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| Contact details
(phone/fax//e-mail//address): |
| // rfr@amnh.org // Division of Vertebrate Zoology – Ornithology, American Museum of Natural History, Central Park West @ 79th Street, New York, NY 10024-5192, 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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WEATHER
CONDITIONS
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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: |
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Breeding conditions:
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We have monitored nesting phenology and nest density of Lesser Snow Geese since research began at La Perouse Bay in 1969. Nests within a 50 m radius circle of a pole are enumerated annually about 10 days into the 24 day incubation period. We also determine the float status of eggs to estimate the dates of nest initiation and projected hatch date.
Unlike in 2006, there was some heterogeneity in the projected dates of initiation and hatching for Lesser Snow Geese across the region. This probably reflects differential availability of nesting habitat. In one site at least 30% of the potential nesting habitat was still under water on 30 May when we collected data there. The presence of a substantial number of clutches containing 6 or more eggs is also consistent with restriction of available nesting habitat (modal clutch size for this colony is 4 eggs). In such circumstances, females that can not find a suitable nesting site will parasitize the nests of females with sites. Even in the face of this heterogeneity, this season appeared to be about one week earlier than our 38 year running average.
Coupled with this year's below average temperatures during late May and early June and the delayed growing season, this advance in the hatching date does not bode well for the success of the goslings. There was no growth of above-ground vegetation (as of 12 June 2007) so there was little if anything for the goslings to feed on.
There has been a general decline in nesting density at all three of our long-term sites since 1996. In 2005, there was a dramatic increase at all three sites. In 2006, density declined at all three sites. In 2007 trends were both positive and negative between the sites. Perhaps the most important point is that nesting densities have not returned to the levels seen before the Canadian and US Governments began a program in 1997 to reduce the size of the Mid-continent Population of Lesser Snow Geese.
This year's banding operations commenced on 21-27 July. We were confronted with some of the hottest and driest weather recorded in the region. Over the banding period there was little wind and no rain. The air temperature averaged 25.7°C and topped 30°C on 4 days. This is 8.4°C above the 30-year average. Even under these conditions we were able to process and release a total of 5,079 Lesser Snow Geese (including a few Ross's Geese), and suffered only 6 site fatalities (~0.1%). We had a higher than average number of yearlings, probably reflecting a substantial recruitment from 2006. This will be in contrast to recruitment from this year which is quite low - gosling/adult ratio = 0.54. This most likely reflects the year's phenology when hatching preceded growth of forage graminoids by at least a week.
We decided to develop a helicopter based aerial survey that would provide an index of local Arctic Fox abundance and activity. The index could be monitored through time and evaluated in consort with indices for plant and herbivore abundance both locally and across the various sites in the overall program. Arctic foxes are primarily found on the north/south remnant gravel beach ridges in the eastern portions of the Wapusk National Park. Owing to both urine and faeces left by the foxes, as well as carcasses and remnants of prey items, the dens are generally surrounded by lush growths of Lyme Grass that are especially visible by mid-August. We stopped at a selected number of dens, that we all felt were active, to make a preliminary assessment of the foods being consumed. Foxes at all of the active dens we visited make extensive use of goslings and adults of both Lesser Snow and Canada geese. A more complete evaluation of diet will be made by examining fox scat collected at the dens. A cursory examination of scats indicated the presence of both goose feathers and hair, likely from lemmings or other microtines, at some dens.
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Rodent dynamics:
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Rodent species recorded:
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Summary
of fauna studies: |
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