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Life history theory assumes a trade-off between reproduction and survival. Investigations of this trade-off in birds have focused primarily on costs of rearing altricial young, because such costs are assumed to be low in species with precocial young. We experimentally manipulated nest success to test for a trade-off between (1) raising offspring for up to 1 yr after successfully nesting and (2) survival in female Ross's Geese (Chen rossii), a species with self-feeding, precocial young. We used multistate capture-resighting analysis that also incorporated recoveries of dead birds for inference about survival. We detected a general negative effect of successful nesting on survival, whereby point estimates of annual survival for successfully nesting females were consistently lower than those for failed nesters. Failed nesters had a greater proportion of mortality attributable to hunting, judging from their higher rates of reported mortality by hunters compared to successful nesters; thus, a cost of breeding associated with successful nesting likely resulted from natural mortality factors during incubation and brood rearing, and not from exploitation by humans. [ABSTRACT FROM AUTHOR]

Colored neckbands are known to reduce survival rates of geese, but the underlying cause for lower survival is unknown. We tested the hypothesis that hunters cause this lower survival rate by actively targeting neckbanded geese. We evaluated this hypothesis by estimating recovery and survival rates of adult Ross's geese ( Chen rossii) at both Queen Maud Gulf (QMG) and McConnell River (MCR) Migratory Bird Sanctuaries carrying each of 3 marker combinations: 1) standard legbands ( n = 11,321) for basic estimates of recovery and survival rates; 2) standard legbands and colored neckbands ( n = 8,587) as the marked sample most detectable and thus most vulnerable to targeting by hunters; and 3) standard legbands and white neckbands ( n = 6,501) as the sample exposed to the general risks of carrying neckbands but only minimally detectable by hunters, if at all. Recovery rates (±95% CL) of Ross's geese were lowest for those marked with legbands (0.024 ± 0.004 at MCR and 0.016 ± 0.003 at QMG) and highest for those marked with neckbands, regardless of neckband color (0.042 ± 0.005 at MCR and 0.035 ± 0.005 at QMG). Survival rates (±95% CL) were indistinguishable between geese marked with color and white neckbands (0.54 ± 0.08 at MCR and 0.52 ± 0.08 at QMG), but lower than those marked with standard legbands only (0.72 ± 0.17 at MCR and 0.83 ± 0.23 at QMG). Geese marked with white neckbands were recovered at rates similar to those marked with color neckbands, suggesting that hunter selection of color neckbands did not contribute greatly to lower survival rates in neckbanded geese. Rather, results suggest that neckbanded geese, regardless of neckband visibility, are more vulnerable to hunters than are geese marked only with legbands. © 2012 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Large increases in several populations of North American arctic geese have resulted in ecosystem-level effects from associated herbivory. Consequently, some breeding populations have shown density dependence in recruitment through declines in food availability. Differences in population trajectories of lesser snow geese ( Chen caerulescens caerulescens; hereafter snow geese) and Ross's geese ( C. rossii) breeding in mixed-species colonies south of Queen Maud Gulf (QMG), in Canada's central arctic, suggest that density dependence may be limiting snow goose populations. Specifically, long-term declines in age ratios (immature:adult) of harvested snow geese may have resulted from declines in juvenile survival. Thus, we focused on juvenile (first-year) survival of snow and Ross's geese in relation to timing of reproduction (annual mean nest initiation date) and late summer weather. We banded Ross's and snow geese from 1991 to 2008 in the QMG Migratory Bird Sanctuary. We used age-structured mark-recapture models to estimate annual survival rates for adults and juveniles from recoveries of dead birds. Consistent with life history differences, juvenile snow geese survived at rates higher than juvenile Ross's geese. Juvenile survival of both species also was lower in late seasons, but was unrelated to arctic weather measured during a 17-day period after banding. We found no evidence of density dependence (i.e., a decline in juvenile survival over time) in either species. We also found no interspecific differences in age-specific hunting vulnerability, though juveniles were more vulnerable than adults in both species, as expected. Thus, interspecific differences in survival were unrelated to harvest. Lower survival of juvenile Ross's geese may result from natural migration mortality related to smaller body size (e.g., greater susceptibility to inclement weather or predation) compared to juvenile snow geese. Despite lower first-year survival, recruitment by Ross's geese may still be greater than that by snow geese because of earlier sexual maturity, greater breeding propensity, and higher nest success by Ross's geese. © 2012 The Wildlife Society. [ABSTRACT FROM AUTHOR]

We studied harvest of Ross's geese in North America by examining recoveries from 30,774 Ross's geese marked from 1989 to 2001 in Queen Maud Gulf Migratory Bird Sanctuary (QMGMBS), Nunavut, in Canada's central arctic. Recoveries reported by hunters in North America provided information about timing and location of harvest for 2,152 birds. Banded Ross's geese were shot and reported mostly from the U.S. (68%) and Canada (30%), but also Mexico (2%) during the study. From 1989 to 2001, there have been eastward shifts in distribution of recoveries from the Pacific Flyway to the midcontinent in the U.S., and from Alberta to Saskatchewan in Canada. Harvest in Canada was concentrated in southern Saskatchewan (85%), whereas U.S. distribution of recoveries was much broader with most recoveries from the Pacific (49%), Central (39%), and Mississippi (12%) Flyways. Continental harvest of Ross's geese began to increase in 1994 concurrent with liberalization of hunting regulations in the Canadian Prairie provinces and the Central and Mississippi Flyways, and the increased propensity of U.S. hunters, who now account for 90% of the continental harvest, to hunt outside of the U.S. Harvest from further liberalization of hunting regulations for light geese as part of the U.S. conservation order has accounted for ⩽15% of continental harvest annually since 1998. Nevertheless, increased harvest of Ross's geese from the 1989 hunting season (∼8,000 birds) to the 2001 season (∼90,000 birds) best accounted for annual variation in adult survival, but was unrelated to juvenile survival. Survival of adults was >0.91 before 1994 but declined to ∼0.80 by 1998–2000 hunting seasons. Juvenile survival was relatively stable among years and ranged from 0.33 to 0.41. We found that mortality probability of adults marked with neckbands was 1.94 to 2.62 times higher than for adults without neckbands, but only 1.08 to 1.13 times higher in respective groups of juvenile Ross's geese. Thus, we advise against use of neckbands for estimation of survival in Ross's geese. The similarity and mixing of Ross's geese with snow geese in western and central North America are impediments to separate harvest management of each species. However, geographical adjustment of harvest regulations for Ross's geese in Canada is advised, with the dual objective of reducing midcontinent snow geese while conserving populations of Ross's geese on traditional winter areas in the Pacific Flyway. We recommend Ross's geese continue to be marked with legbands in QMGMBS, their principal breeding range, at least as long as liberal harvest regulations remain in place for reduction of midcontinent snow geese. [ABSTRACT FROM AUTHOR]