The absence of a rigorous mechanism for prioritizing investment in endangered species management is a major implementation hurdle affecting recovery. Here, we present a method for prioritizing strategies for endangered species management based on the likelihood of achieving species' recovery goals per dollar invested. We demonstrate our approach for 15 species listed under Canada's Species at Risk Act that co-occur in Southwestern Saskatchewan. Without management, only two species have >50% probability of meeting recovery objectives; whereas, with management, 13 species exceed the >50% threshold with the implementation of just five complementary strategies at a cost of $126m over 20 years. The likelihood of meeting recovery objectives rarely exceeded 70% and two species failed to reach the >50% threshold. Our findings underscore the need to consider the cost, benefit, and feasibility of management strategies when developing recovery plans in order to prioritize implementation in a timely and cost-effective manner. K E Y W O R D Scomplementarity, cost-effectiveness, critical habitat, expert elicitation, multiobjective optimization, multispecies conservation, Priority Threat Management, priority-setting, recovery planning, SARA, Saskatchewan, South of the Divide, species at risk, structured decision making, triageThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Abstract-Populations of several species of North American sea ducks have declined in the past few decades. Exposure to environmental contaminants, particularly metals, has been proposed as one of many possible factors contributing to these declines. Population dynamics are influenced by survival rates and breeding effort. In the present study, we examined the relationships between blood metal concentrations (Cd, Pb, Se, and Hg) and apparent annual survival and recapture probabilities (the latter as a surrogate for breeding effort) in adult females of two sea duck species, the king eider (Somateria spectabilis) and the white-winged scoter (Melanitta fusca), both of which have experienced declines in continental population during in recent years. No support was found for the hypothesis that exposure of white-winged scoters to these metals or of king eiders to Cd, Se, and Pb adversely affected probabilities of apparent annual survival. We detected a weak negative relationship ( ϭ Ϫ0.833) between Hg and annual survival ␤ of king eiders, but the 90% confidence interval of the slope estimate overlapped zero (Ϫ2.439 to ϩ0.672). Recapture probabilities were unrelated to concentrations of Cd, Se, and Pb in either species. Evidence indicated that Hg concentrations affected recapture probability in white-winged scoters ( ϭ Ϫ194.77; 90% confidence interval, Ϫ203.770 to Ϫ185.778). Mercury levels were low ␤ in both species, and blood samples may not adequately represent long-term exposure to Hg. Therefore, conclusions regarding Hg effects on these birds should be considered with caution.

Events during duckling growth can influence waterfowl population dynamics. To gain insight into King Eider (Somateria spectabilis) brood ecology, we monitored 111 and 46 individually marked ducklings from broods of 23 and 11 radiomarked King Eiders during 2000 and 2001, respectively. We used capture-mark-resight data to model apparent survival of King Eider ducklings and broods, and multistratum analysis to estimate probabilities of (1) movement among habitats and (2) apparent survival of ducklings that used various habitats. In addition, we recorded length of stay for 7 and 18 radiomarked females with failed nesting attempts during 2000 and 2001, respectively. Complete loss of individual broods accounted for 84% of all duckling mortality (106 of 126 mortalities), with most brood loss (74%; 17 of 23 broods lost) within the first two days after hatch. Estimated apparent survival of ducklings to 24 days of age was 0.10 (95% CI: 0.05 to 0.15). Apparent survival of broods was estimated to be 0.31 (95% CI: 0.13 to 0.50). Our data suggested an interaction between female size and hatch date, whereby larger females whose ducklings also hatched earlier raised more ducklings than either small females or those with ducklings that hatched later. Overland brood movements ≥1 km occurred in both years, and survival was greatest for ducklings on smaller ponds away from the central nesting area at Karrak Lake, Nunavut. Females that experienced nest failure and total brood loss left the study area earlier than females with surviving ducklings.Écologie d'élevage des couvées de Somateria spectabilis : Corrélations avec la survie des canetons

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We used banding data from King Eiders (Somateria spectabilis) at Karrak Lake, Nunavut, Canada, during 2001 and 2002 in conjunction with analysis of naturally occurring stable isotopes (13C, 15N) from feathers to connect winter and breeding areas of individuals. We also investigated the occurrence of winter philopatry among nesting females, and examined cross-seasonal effects of wintering area on subsequent breeding. Isotopic data suggested that 66–73% of this central-arctic breeding population wintered to the west (i.e., Bering Sea and North Pacific) and the remaining 24–37% wintered to the east (i.e., west Greenland, northwest Atlantic). In contrast, limited band recoveries from hunter-killed King Eiders marked at the same breeding location suggested that about 56% of individuals were shot in eastern wintering areas. These differences likely reflect stronger hunting pressures along the coast of Greenland, which result in more band recoveries for this area. Our results suggest that female King Eiders were not strongly philopatric to wintering areas among years. Individuals that wintered in western seas initiated nests 1.9 days earlier and had slightly larger clutches during early initiation relative to females that wintered in the east. Nest parasitism appeared to be biased toward earlier nesters, many of which wintered in the west. Female condition during incubation did not vary by wintering area. Our results have important implications for gene flow and for potentially associating wintering-area conditions with overall demography and individual fitness of King Eiders. ¿Pasar el Invierno en el Este o en el Oeste? Heterogeneidad en la Filopatría al Sitio de Invernada en una Población de Somateria spectabilis del Ártico Central Resumen. Para conectar las áreas de invernada con las de reproducción en la especie Somateria spectabilis, utilizamos datos de aves anilladas durante 2001 y 2002 en Karrak Lake, Nunavut, Canadá, junto con análisis de isotópos estables que se encuentran en la naturaleza y en las plumas (13C, 15N). También investigamos la existencia de filopatría al sitio de invernada entre hembras nidificantes, y examinamos los efectos del área de invernada sobre la reproducción subsiguiente. Los datos isotópicos sugirieron que el 66–73% de los individuos de esta población que nidifica en el Ártico central pasa el invierno al oeste (i.e., Mar de Bering, Pacífico Norte) y que el 24–37% restante lo hace al este (i.e., oeste de Groenlandia, noroeste del Atlántico). En contraste, los pocos anillos puestos en la misma localidad reproductiva que fueron recobrados por cazadores, mostraron que alrededor del 56% de los individuos fueron cazados en áreas de invernada ubicadas al este. Estas diferencias probablemente reflejan que las presiones de cacería son más fuertes a lo largo de la costa de Groenlandia, lo que conlleva a que se recobren más anillos en esta área. Nuestros resultados sugieren que las hembras de S. spectabilis no son fuertemente filopátricas a sus sitios de invernada entre años. Los individuos que invernaron en los mares del oeste iniciaron sus nidos 1.9 días más temprano y tuvieron nidadas ligeramente más grandes durante la etapa temprana de iniciación en comparación con las hembras que invernaron al este. El parasitismo de nidos pareció estar sesgado hacia las aves que nidificaron temprano, muchas de las cuales invernaron en el oeste. La condición de las hembras durante la incubación no varió entre áreas de invernada. Nuestros resultados tienen implicaciones importantes en términos de flujo génico y potencialmente para asociar las condiciones de las áreas de invernada con la demografía en general y con la adecuación biológica de los individuos de esta especie.