scholarly journals Polygenic Variation and Stabilizing Selection in a Wild Population of Lesser Snow Geese (Anser caerulescens caerulescens)

1982 ◽  
Vol 120 (4) ◽  
pp. 543-547 ◽  
Author(s):  
Fred Cooke ◽  
C. Scott Findlay
Keyword(s):  
Wild Population ◽  
Stabilizing Selection ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Anser Caerulescens Caerulescens ◽  
Anser Caerulescens ◽  
Polygenic Variation

scholarly journals A comparison of drone imagery and ground-based methods for estimating the extent of habitat destruction by lesser snow geese (Anser caerulescens caerulescens) in La Pérouse Bay

PLoS ONE ◽  
2019 ◽  
Vol 14 (8) ◽  
pp. e0217049 ◽  
Author(s):  
Andrew F. Barnas ◽  
Brian J. Darby ◽  
Gregory S. Vandeberg ◽  
Robert F. Rockwell ◽  
Susan N. Ellis-Felege
Keyword(s):  
Habitat Destruction ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Anser Caerulescens Caerulescens ◽  
Anser Caerulescens

scholarly journals Winter carry-over effects on spring body condition driven by agricultural subsidies to Lesser Snow Geese (Anser caerulescens caerulescens)

2020 ◽  
Vol 15 (2) ◽  
Author(s):  
Drew N. Fowler ◽  
Elisabeth B. Webb ◽  
Mark P. Vrtiska ◽  
Keith A. Hobson
Keyword(s):  
Body Condition ◽  
Agricultural Subsidies ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Anser Caerulescens Caerulescens ◽  
Anser Caerulescens ◽  
Carry Over

Corrections: Genetic and Environmental Components of Clutch Size Variance in a Wild Population of Lesser Snow Geese (Anser cacurlescens caerulescens)

Evolution ◽  
1987 ◽  
Vol 41 (2) ◽  
pp. 453 ◽  
Author(s):  
C. Scott Findlay ◽  
Fred Cooke
Keyword(s):  
Clutch Size ◽  
Wild Population ◽  
Snow Geese ◽  
Lesser Snow Geese

Effects of parasitic infections on clutch size of lesser snow geese from a northern breeding colony

1994 ◽  
Vol 72 (3) ◽  
pp. 541-544 ◽  
Author(s):  
Michael Clinchy ◽  
Ian K. Barker
Keyword(s):  
Clutch Size ◽  
Parasite Load ◽  
Convincing Evidence ◽  
Parasitic Infections ◽  
Breeding Colony ◽  
Proximate Cause ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Anser Caerulescens Caerulescens

A density-dependent decline in the average clutch size of lesser snow geese (Anser caerulescens caerulescens) occurred from 1973 to 1989 at the breeding colony on the shores of La Pérouse Bay, Manitoba. An increase in average parasite load was hypothesized to be one of the two most likely causes of this decline. We shot 28 incubating adult female lesser snow geese at the La Pérouse Bay colony and examined the carcasses for parasites to determine if there was any proximate association between parasitic infections and the size of the clutch a female laid. We found no convincing evidence that parasitic infections were the proximate cause of any reduction in clutch size. In the absence of evidence of any direct effect of parasites, we conclude that an increase in the average parasite load is probably not the cause of the long-term decline in clutch size at La Pérouse Bay. By default, we suggest that increased intraspecific competition for food at the staging areas on the migratory flyway is the most likely cause of the decline in clutch size.

Liberalized harvest regulations have not affected overabundant Snow Geese in Northern Manitoba

The Condor ◽  
2019 ◽  
Vol 121 (2) ◽  
Author(s):  
David N Koons ◽  
Lise M Aubry ◽  
Robert F Rockwell
Keyword(s):  
Management Effectiveness ◽  
Snow Goose ◽  
The North ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Anser Caerulescens Caerulescens ◽  
New Findings ◽  
Lesser Snow Goose ◽  
Adaptive Resource ◽  
Improved Methods

Abstract Large amounts of money are spent each year to control overabundant species that imperil biodiversity and ecosystem functioning across the globe. Lesser Snow Geese (Anser caerulescens caerulescens) are emblematic of this issue, as their overabundance has affected a whole suite of plant, insect, and bird communities via a trophic cascade that managers have attempted to stop before it spreads further across the North American (sub)Arctic. To achieve this goal, liberalized harvest measures designed to decrease Lesser Snow Goose survival and abundance were implemented almost 2 decades ago. Our previous quantitative assessment of management effectiveness indicated that the growing Lesser Snow Goose population quickly overwhelmed a satiated hunter population despite liberalized harvest regulations, eventually reducing the fraction of Lesser Snow Geese being harvested each year. Consistent with the philosophy of adaptive resource management, we apply improved methods to additional years of monitoring data to evaluate the ongoing impact of harvest conservation efforts on Lesser Snow Goose harvest rates. Our previous results suggested little effect of liberalized harvest regulations on harvest rates, but our new findings suggest even less of an impact. Harvest rates have recently stabilized at ~3%, the lowest levels observed over the last 48 yr of our study. Barring adverse effects of environmental change on natural mortality or reproductive success, additional measures will need to be taken to reduce Lesser Snow Goose overabundance and their ecosystem damage.

scholarly journals Recruitment and the Timing of Reproduction in Lesser Snow Geese (Chen caerulescens caerulescens)

The Auk ◽  
1984 ◽  
Vol 101 (3) ◽  
pp. 451-458 ◽  
Author(s):  
Fred Cooke ◽  
C. Scott Findlay ◽  
Robert F. Rockwell
Keyword(s):  
Reproductive Success ◽  
Natural Populations ◽  
Breeding Population ◽  
Relative Fitness ◽  
Stabilizing Selection ◽  
Chen Caerulescens ◽  
Snow Geese ◽  
Lesser Snow Geese ◽  
Chen Caerulescens Caerulescens ◽  
Selection For

Abstract Recruitment of offspring into a breeding population of Lesser Snow Geese (Chen caerulescens caerulescens) at La Perouse Bay, Manitoba was used as a measure of reproductive success to assess the relative fitness of females who hatched their clutches early, middle, and late in the breeding season. In three of seven seasons investigated, goslings from early-hatching clutches showed significantly greater recruitment rates than their middle- or late-hatching counterparts. No significant differences in recruitment rates were detected in the other four seasons, although early-hatching clutches showed numerically higher recruitment rates in three of these seasons. There is, therefore, some indication of directional selection for early breeding. This conclusion contrasts with that drawn by Cooke and Findlay (1982), who, using fledging success as a measure of reproductive fitness, showed that females whose clutches hatched in the middle period had the highest fitness and concluded that the population was being exposed to stabilizing selection for synchronization. The discrepancy between these results and those presented in this paper indicates that conclusions concerning the action of selection in natural populations depend heavily upon the stage of the life cycle during which reproductive success is estimated. As such, evolutionary biologists must be cautious of relying too heavily on measures taken too early in the life of the organism.

Seasonal changes in thyroid activity in the lesser snow goose (Anser caerulescens caerulescens) including reference to embryonic thyroid activity

1980 ◽  
Vol 58 (6) ◽  
pp. 1144-1150 ◽  
Author(s):  
R. R. Campbell ◽  
J. F. Leatherland
Keyword(s):  
Thyroid Activity ◽  
Cell Height ◽  
Lesser Snow Geese ◽  
Anser Caerulescens Caerulescens ◽  
Thyroid Epithelial Cell ◽  
Lesser Snow Goose ◽  
Apparent Correlation ◽  
Anser Caerulescens ◽  
Gonadal Recrudescence ◽  
Plasma Triiodothyronine

Plasma thyroxine (T4) levels in adult lesser snow geese (Anser caerulescens caerulescens) increased concomitantly with gonadal recrudescence and remained elevated until shortly before moult. This pattern of declining plasma T4 concentrations preceding moult was evident in gosling, yearling, and adult birds. Plasma triiodothyronine (T3) concentrations did not change significantly throughout the year. There was no apparent correlation between plasma thyroid hormone levels and thyroid weight or thyroid epithelial cell height. Plasma levels of both T3 and T4 increased in goslings shortly before hatch and on day 20 of incubation reached levels (0.58 ± 0.36 and 19.5 ± 2.5 ng∙mL−1, respectively) similar to those found in the plasma of newly hatched birds (0.76 ± 0.24 and 36.0 ± 6.5, respectively).

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