Explaining co-occurrence among helminth species of lesser snow geese ( Chen caerulescens ) during their winter and spring migration

Oecologia ◽  
1999 ◽  
Vol 120 (4) ◽  
pp. 613-620 ◽  
Author(s):  
M. R. Forbes ◽  
R. T. Alisauskas ◽  
J. D. McLaughlin ◽  
K. M. Cuddington

10.2307/4924 ◽  
1988 ◽  
Vol 57 (2) ◽  
pp. 553 ◽  
Author(s):  
Laurene Ratcliffe ◽  
R. F. Rockwell ◽  
F. Cooke


The Condor ◽  
2002 ◽  
Vol 104 (2) ◽  
pp. 432-436 ◽  
Author(s):  
Jason D. Weckstein ◽  
Alan D. Afton ◽  
Robert M. Zink ◽  
Ray T. Alisauskas

AbstractWe reanalyzed Quinn's (1992) mtDNA control region data set including new sequences from nine Lesser Snow Geese (Chen caerulescens caerulescens) and 10 Ross's Geese (Chen rossi) and found the same divergent lineages that Quinn (1992) attributed to vicariant separation of Lesser Snow Goose populations during the Pleistocene. However, peculiar patterns of mtDNA control region sequence variation, including a multimodal mismatch distribution of mtDNA sequences with two levels of population structuring and the sharing of two divergent haplotype lineages, are consistent with two hybridization episodes in Chen geese. Comparisons of mtDNA variation with historical and allozyme data sets compiled by Cooke et al. (1988) are consistent with the hypothesis that sharing of two mtDNA haplotype lineages between Ross's Goose and Lesser Snow Goose resulted from hybridization (Avise et al. 1992). Furthermore, population structure found within one haplotype cluster is consistent with Cooke et al.‘s (1988) hypothesis of past allopatry between blue and white Lesser Snow Geese.Hibridización y Subdivisión dentro y entre Poblaciones de Chen rossi y Chen caerulescens caerulescens: Una Perspectiva MolecularResumen. Reanalizamos los datos de la región de control del ADN mitocondrial (ADNmt) de Quinn (1992), junto con nuevas secuencias de nueve individuos de la especie Chen caerulescens caerulescens y 10 de Chen rossi. Encontramos los mismos linajes divergentes que Quinn (1992) atribuyó a la separación vicariante de las poblaciones de C. c. caerulescens durante el Pleistoceno. Sin embargo, encontramos que las dos especies comparten dos linajes de haplotipos divergentes, y la distribución de “mismatch” en secuencias del ADNmt mostró multimodalidad con dos niveles de estructuración de la población. Estos patrones peculiares están de acuerdo con la hipótesis de que hubo dos episodios de hibridización en gansos del género Chen. Los datos históricos y de aloenzimas compilados por Cooke et al. (1988) también apoyan esta hipótesis (Avise et al. 1992). Además, la estructura de la población dentro de un grupo de haplotipos es consistente con la hipótesis de Cooke et al. (1988) acerca de la pasada alopatría entre los morfos azul y blanco de C. c. caerulescens.





2006 ◽  
Vol 176 (5) ◽  
pp. 453-462 ◽  
Author(s):  
Jón Einar Jónsson ◽  
Alan D. Afton ◽  
Dominique G. Homberger ◽  
William G. Henk ◽  
Ray T. Alisauskas


2008 ◽  
Vol 122 (1) ◽  
pp. 34
Author(s):  
Richard H. Kerbes ◽  
Katherine M. Meeres ◽  
James E. Hines ◽  
David G. Kay

We surveyed the Lesser Snow (Chen caerulescens caerulescens) and Ross’s geese (Chen rossii) of Jenny Lind Island, Nunavut, using aerial photography in June 1988, 1998, and 2006, and a visual helicopter transect survey in July 1990. The estimated number of nesting geese was 39 154 ± SE 2238 in 1988, 19 253 ± 2323 in 1998, and 21 572 ± 1898 in 2006. In 1988 an estimated 2.7% of the nesting geese were Ross’s. The July 1990 population of adult-plumaged birds was 25 020 ± 3114. The estimated percentage blue morph among Snow and Ross’s geese was 19.0% in 1988, 25.1% in 1989, 23.0% in 1990 and 21.1% in 2006. Estimated pre-fledged Snow Goose productivity was 47% young in 1989 and 46% in 1990. Combined numbers of Snow and Ross’s geese on Jenny Lind Island grew over 250 fold, from 210 adults in 1962-1966 to 54 100 adults in 1985. Numbers subsequently declined, to 42 200 in 1988, 25 000 in 1990, 20 300 in 1998, and 26 400 in 2006. Population decline between 1985 and 1990 was consistent with anecdotal reports by others that die-offs of Snow Geese occurred in 1984, 1985 and 1989, and with our August 1989 fieldwork which found evidence of habitat degradation and malnourishment of young geese. In spite of limited food resources on Jenny Lind Island, the colony continued to exist in 2006 at near its 1990 and 1998 levels. Further studies there could provide insights for management of the overabundant mid-continent Snow Goose population and its arctic habitats.



1979 ◽  
Vol 57 (12) ◽  
pp. 2292-2302 ◽  
Author(s):  
John P. Kelsall ◽  
Roland Burton

Results are reported of experimental work done to clarify problems and unknowns involved in identifying origins of lesser snow geese through computer-controlled, X-ray spectrometric analyses of primary flight feathers. Materials from wild and captive populations of lesser snow geese (Chen caerulescens caerulescens) were used. The use of an X-ray tube source of irradiation was successfully introduced to previously described techniques. Practical investigation of sample size for the generation of discriminant functions suggests that 30 samples per population are a barely adequate minimum and that 40 or more should be used.Given adequate sample sizes, and suitably different populations, the classification process overrides differences attributable to sex, age, and "Feather year" with great accuracy. With small sample sizes, however, those differences will dampen the accuracy of discrimination and classification, as will increasing numbers of populations. Examination of feathers from a captive flock, maintained for 4 years, shows statistically insignificant sexual differences, significant "within-year" changes in feather chemistry between October and May, and moderately consistent discrimination between year classes. Some of the chemical variables involved in the observed differences are examined.





Waterbirds ◽  
2017 ◽  
Vol 40 (1) ◽  
pp. 11-23 ◽  
Author(s):  
Robert M. Burgess ◽  
Robert J. Ritchie ◽  
Brian T. Person ◽  
Robert S. Suydam ◽  
John E. Shook ◽  
...  


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