Body Condition, Migration, and Timing of Reproduction in Snow Geese: A Test of the Condition‐Dependent Model of Optimal Clutch Size

2003 ◽  
Vol 162 (1) ◽  
pp. 110-121 ◽  
Author(s):  
Joël Bêty ◽  
Gilles Gauthier ◽  
Jean‐François Giroux

1987 ◽  
Vol 130 (6) ◽  
pp. 839-863 ◽  
Author(s):  
R. F. Rockwell ◽  
C. S. Findlay ◽  
F. Cooke


The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 156-161 ◽  
Author(s):  
Julien Mainguy ◽  
Joël Bêty ◽  
Gilles Gauthier ◽  
Jean-François Giroux

Abstract A spring hunt was implemented on the staging areas of Greater Snow Geese (Chen caerulescens atlantica) in Quebec in 1999 and 2000. We evaluated whether this activity, which occurred during the period of spring nutrient storage, may have affected the body condition and reproductive effort of laying geese. We collected laying females in years with a spring hunt (1999–2000, n = 34) and compared them with birds collected in years without a hunt (1989–1990, n = 10). All indices of body condition and clutch size were significantly lower in years with a hunt than in years without, and laying dates were delayed. Tracking of radio-marked females on the staging and breeding areas showed that a lower proportion of females reached the nesting areas in years with a hunt (28% in 1999–2000, n = 80) than in years without (85% in 1997–1998, n = 80) and that fewer females nested (9% vs. 56%, respectively). Our results suggest that the spring hunt negatively affected nesting geese. ¿Son Afectadas por la Cacería de Primavera la Condición Física y el Esfuerzo Reproductivo de Chen caerulescens atlantica? Resumen. La cacería de primavera fue implementada en áreas de escala de Chen caerulescens atlantica en Quebec en 1999 y 2000. Evaluamos si la cacería, que se llevó a cabo durante el período primaveral de acumulación de nutrientes, pudo haber afectado la condición fisica y el esfuerzo reproductivo de los gansos. Colectamos hembras que estuvieran poniendo huevos en años con cacería de primavera (1999–2000, n = 34) y las comparamos con aves colectadas en años sin cacería (1989–1990, n = 10). Todos los índices de la condición física y del tamaño de la nidada fueron significativamente menores en años con cacería que en años sin cacería, y se retrasaron las fechas de puesta. El seguimiento de hembras marcadas con radio en áreas de escala y cría mostró que una menor proporción llegó a las áreas de nidificación en años con cacería (28% en 1999–2000, n = 80) que en años sin cacería (85% en 1997–1998, n = 80), y que menos hembras nidificaron (9% vs. 56%, respectivamente). Nuestros resultados sugieren que la cacería de primavera afecta negativamente a los gansos nidificantes.



Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.



The Auk ◽  
2006 ◽  
Vol 123 (2) ◽  
pp. 405-418 ◽  
Author(s):  
Jón Einar Jónsson ◽  
Alan D. Afton ◽  
Ray T. Alisauskas ◽  
Cynthia K. Bluhm ◽  
Mohamed E. El Halawani

AbstractWe investigated effects of ecological and physiological factors on brood patch area and prolactin levels in free-ranging Lesser Snow Geese (Chen caerulescens caerulescens; hereafter “Snow Geese”) and Ross's Geese (C. rossii). On the basis of the body-size hypothesis, we predicted that the relationships between prolactin levels, brood patch area, and body condition would be stronger in Ross's Geese than in the larger Snow Geese. We found that brood patch area was positively related to clutch volume and inversely related to prolactin levels in Ross's Geese, but not in Snow Geese. Nest size, nest habitat, and first egg date did not affect brood patch area in either species. Prolactin levels increased as incubation progressed in female Snow Geese, but this relationship was not significant in Ross's Geese. Prolactin levels and body condition (as indexed by size-adjusted body mass) were inversely related in Ross's Geese, but not in Snow Geese. Our findings are consistent with the prediction that relationships between prolactin levels, brood patch area, and body condition are relatively stronger in Ross's Geese, because they mobilize endogenous reserves at faster rates than Snow Geese.Factores Ecológicos y Fisiológicos que Afectan el Área del Parche de Incubación y los Niveles de Prolactina en Gansos Nidificantes del Ártico



The Condor ◽  
2002 ◽  
Vol 104 (1) ◽  
pp. 156 ◽  
Author(s):  
Julien Mainguy ◽  
Joël Bêty ◽  
Gilles Gauthier ◽  
Jean-François Giroux






1975 ◽  
Vol 109 (970) ◽  
pp. 677-699 ◽  
Author(s):  
Warren Y. Brockelman


2000 ◽  
Vol 64 (3) ◽  
pp. 875 ◽  
Author(s):  
Veronique Morez ◽  
Gilles Gauthier ◽  
Austin Reed
Keyword(s):  


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