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RESPONDENT
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Gilles Gauthier
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SITE NAME
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Bylot Island, Nunavut, Canada
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| Contact details
(phone/fax//e-mail//address): |
| // Gilles.Gauthier@bio.ulaval.ca // Departement de biologie & Centre d'etudes nordiques, Universite de Laval, St. Foy, Quebec City, Quebec, G1K 7P4 Canada
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PROJECT DETAILS |
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Project name:
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Population Study of Greater Snow Geese on Bylot Island (Nunavut) in 2002
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Start of survey:
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End
of survey: |
Team
size: |
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30.05
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21.08
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5
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WEATHER
CONDITIONS
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Weather conditions: |
| The spring 2002 was characterized by an early snowmelt, mostly due to a relatively thin snow-pack. Snow depth on 2 June was 26 cm compared to a long-term average of 35 cm. Temperature in spring was also relatively mild with an average air temperature of -0.94øC between 20 May-20 June compared to a long-term average of -0.32øC. Consequently, the rate of snow-melt was rapid and comparable to years with early spring such as 1997 and 1998. Precipitation was low in June (10 mm), including a few light snowfalls (4 cm). However, summer temperatures were generally cool with little sunshine and frequent precipitations (38 mm in July).
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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 found signs of fox activity (digging or fresh prey remains) at 6% of known denning sites (n = 48) compared to 47% in 2001 and 46% in 2000. No litters were seen this year compared to 8 in 2001 and 7 in 2000. This suggests that fox breeding activity had declined drastically and was very low in 2002. Again this year, no Snowy Owl nests were found at either study area compared to 13 nests in 2000.
Despite the early snow-melt, the arrival of Greater Snow Geese on Bylot Island was much later than in most years and similar to 2000, a year with a relatively late snow-melt. Our first pair count on 1 June on the hills surrounding the Base-camp Valley was 28 pairs, and up until the complete snowmelt counts remained low (i.e. <200 pairs), which is unusual. Median egg-laying date was 16 June, which is later than normal. This is very surprising given the favourable conditions in early June (i.e. early snow-melt). It is noteworthy that since the instauration of the spring hunt in 1999, nest initiation has been later than the long-term average in three years and near normal in the fourth. Our field observations suggest that the reproductive effort of geese was low at the main breeding colony (Camp-2) and no nest were found at the Base-camp Valley (even though the latter site is mostly a brood-rearing area, a low density of nesting geese is found there in most years). Average clutch size was 3.43, which is below the long-term average. Again, it is noteworthy that since the instauration of the spring hunt, clutch size has been lower than the long-term average in all four years.
Nesting success (proportion of nests hatching at least one egg) was similar to last year (53% in 2002 compared to 57% last year), which is below the long-term average. Activity of predators at goose nests, especially Arctic foxes (Alopex lagopus), was moderately high this year possibly because the abundance of lemmings (the main prey of predators) was very low on Bylot Island following the peak of 2000. Peak hatch was on 11 July, slightly later than normal. The low reproductive effort observed this year was confirmed by goose faeces density at the end of the summer in wet meadows of the Base-camp Valley, which was among the lowest values recorded (4.4 ñ 1.2 [SE] faeces/m2). Accumulation of faeces was also delayed this year and only started at the end of July, which suggests that arrival of broods on the brood-rearing areas was delayed.
This is the first time in 14 years of monitoring that an early spring (e.g. similar to 1993, 1997 and 1998) did not result in a good breeding performance by geese. Nest predation was moderately high, but not as high as in previous years of lemming crashes (e.g. 1995 and 1999), which is also surprising given the low nest density. The combination of low reproductive effort, late nesting, and moderate nest predation lead to a low young:adult ratio during our banding operation. Based on this statistic, we anticipated a proportion of young in the fall flock around 14%, a low value. However, this prediction was only partially upheld as juvenile counts conducted in Quebec this fall indicated an even lower proportion of young (6%, n = 18,930). It should be noted that our young:adult ratio at banding does not take into account non-breeding adults that do not stay on Bylot Island to molt, a number that was likely high this year due to the low reproductive effort. Therefore, with a proportion of young in the fall flock of 6%, the year 2002 can be classified as a year of breeding failure for Greater Snow Geese (defined as years where this proportion is <10%), comparable to 1999 (2%, the worst breeding failure in over 30 years).
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Rodent dynamics:
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| For our small-mammal survey, we accumulated 1400 trap-nights in the Base-camp Valley split between 2 trapping sites (one lowland and one upland) and 550 trap-nights in the upland habitat at Camp-2. In the Base-camp sites, we captured only 1 Collared Lemming (Dicrostonyx groenlandicus), for an index of abundance of 0.07 lemmings/100 trap-nights, the lowest number since 1995. Lemming abundance at the Camp-2 was also very low (0.19 lemmings/100 trap-nights with only 1 collared lemming captured). Therefore, lemmings continued the decline started in 2001 at the Base-camp Valley following the peak of 2000, and declined dramatically at Camp-2 following a very high density in 2001. Thus, even though the last peak in lemming abundance was not synchronized at our two study sites, lemming populations had crashed at both sites in 2002.
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Rodent species recorded:
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| Latin | Abundance |
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| Dicrostonyx groenlandicus | rare |
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Summary
of fauna studies: |
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