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RESPONDENT
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Gustav Samelius
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SITE NAME
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Egg River, Banks Island, Canada
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| Contact details
(phone/fax//e-mail//address): |
| 306-975-5509/306-975-4089 // Gustaf.Samelius@EC.GC.CA; dana.kellett@ec.gc.ca // Canadian Wildlife Service, 115 Perimeter Road, Saskatoon SK, S7N 0X4, Canada
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PROJECT DETAILS |
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Project name:
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Banks Island Snow Goose Study
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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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| Season phenology: |
average
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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: |
low
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Breeding conditions:
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We estimated that 305,000, 397,000, 186,000, and 439,000 lesser snow geese nested at Egg River in 1995 to 1998, respectively. This is about twice as many geese nesting at Egg River than in the 1980's. Annual variation in number of nesting geese appeared to be related to spring arrival, which may be an important factor affecting the proportion of birds arriving on Banks Island that attempt to breed each year.
Nesting success of lesser snow geese at Egg River showed large variation among years, ranging from 67% and 65% in 1995 and 1997, to 94% and 88% in 1996 and 1998, respectively. This is comparable to nest success recorded for lesser snow geese at other colonies, but of greater annual variation. Both 1995 and 1997 were late years, which probably caused birds to use considerable body reserves while waiting for snow to melt. Late springs have strong effects on nesting performance of lesser snow geese at other colonies and appears to be an important factor affecting nest success at Banks Island.
Most eggs lost to predation by arctic foxes were lost when birds were not by their nests or when the male was away feeding (see Can. J. Zool. 79: 861-866). This further suggests the importance of being in good nutritional condition to successfully complete incubation. We do not have data on egg loss to glaucous gulls, but as gulls do not push geese off of nests, gull predation also may be affected by nest recess, which in turn is influenced by condition of geese.
Gosling survival during the first 2-3 weeks after hatch was 47%, 37%, and 44% from 1996 to 1998, respectively. We suggest that weather conditions and predation may have been important factors affecting brood survival at Banks Island.
Spring arrival was late in 1995 and in 1997 when geese had to wait for about 2 weeks for snow to melt before initiating nests whereas spring arrival was relatively early in 1996 and in 1998 when geese had to wait for less than 1 week before initiating nests (snow was melted before goose arrival in 1996).
The number of arctic foxes frequenting the colony varied between years (X2(3) = 61.81, p < 0.001). Abundance of arctic foxes was highest in 1997 and 1998, when we sighted 75 foxes on 329 km traveled (n = 29 days) and 61 foxes on 395 km traveled (n = 32 days) each year, respectively. In 1995 and 1996, we sighted only 24 foxes in 430 km traveled (n = 31 days) and 19 foxes in 400 km traveled (n = 30 days) each year, respectively. The peak in number of foxes frequenting the colony followed 1 year after the peak in lemming abundance.
The number of nesting glaucous gulls appeared to be similar or slightly increasing among years. In total, we found 51, 64, 68, and 80 nests in 1995 to 1998, respectively. As discussed above, we might have missed a few nests in 1995 and 1996, before we learned on which islands gulls nested.
Except for arctic foxes and glaucous gulls, there were both pomarine and long-tailed jaegers frequenting the colony in all years. In 1996, we confirmed at least two breeding attempts of long-tailed jaegers, and in 1997, we confirmed at least one breeding attempt of long-tailed jaegers. On two separate occasions in 1995, we saw wolves near or within the colony (two wolves on the first occasion and four on the second). In 1998, we saw two wolves ca 1 km outside the colony on one occasion. In 1996 and 1997, we saw no wolves at Egg River Colony.
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Rodent dynamics:
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| Lemming abundance varied among years (Fisher exact test, p = 0.003, n = 16 lemmings trapped in 1439 trap-nights during 4 years) and followed the cycles at other locations on Banks Island, however, of apparently lower magnitude (Dr. N. Larter, Renewable Resources, Inuvuk, NWT, pers. com.). Lemming numbers were highest in 1996, when we captured 11 lemmings in 359 trap-nights and encountered lemmings frequently when traveling in the colony. In 1995, 1997 and 1998, lemming abundance was low and we only caught 1 lemming in 360 trap-nights in 1995 and 2 lemmings in 360 trap-nights in each of 1997 and 1998. In 1995, lemming numbers appeared to be very low and only one other lemming than the one caught was seen during the summer. In 1997 and 1998, lemmings were encountered more frequently than in 1995, especially during the first part of incubation.
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Rodent species recorded:
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Summary
of fauna studies: |
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