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Conflict between cormorants (Phalacrocorax spp.) and humans over fisheries is currently one of the most widespread wildlife management issues in the world. Cormorant impact assessments typically assume a single source of prey near the breeding colony. However, cormorants can fly long distances (>20 km), resulting in fish removal from multiple areas. Knowledge of the source of cormorant prey is critical for fisheries impact assessments. Carbon and nitrogen stable isotopes values from fish in double-crested cormorant (Phalacrocorax auritus) regurgitations revealed several prey sources for breeding birds in northcentral Saskatchewan, Canada. Cormorants also switched feeding locations on a daily and seasonal basis. Foraging patterns inferred by stable isotope analysis closely paralleled observations of relative cormorant densities on different lakes. Up to 80% of prey came from areas well removed from the breeding colony lake ( Les conflits entre cormorans (Phalacrocorax spp.) et humains relatifs a la peche constituent un des problemes de gestion de la faune les plus repandus a l'echelle planetaire. Les evaluations des impacts des cormorans partent generalement de l'hypothese d'une seule source de proies a proximite de la colonie de nidification. Les cormorans peuvent toutefois voler sur de longues distances (>20 km) et ainsi prelever du poisson de plusieurs secteurs. La connaissance des sources de proies des cormorans est essentielle a l'evaluation des impacts sur les peches. Les concentrations d'isotopes stables du carbone et de l'azote de poissons dans les regurgitations de cormorans a aigrettes (Phalacrocorax auritus) revelent l'existence de plusieurs sources de proies pour des oiseaux nidifiant dans le centre nord de la Saskatchewan (Canada). Ces cormorans changent egalement de sites d'alimentation sur des bases quotidienne et saisonniere. Les patrons de quete de nourriture tires de l'analyse des isotopes stables concordent etroitement avec les observations sur la densite relative de cormorans dans differents lacs. Jusqu'a 80 % des proies proviennent de secteurs a bonne distance du lac de la colonie de nidification (, Introduction Conflicts between piscivorous birds and humans over fisheries and aquaculture resources are common and widespread, especially those involving cormorants (Phalacrocorax spp.; Doucette et al. 2011). A predominantly piscivorous diet, [...]

Abstract: A consequence of climate change has been an advance in the timing of seasonal events. Differences in the rate of advance between trophic levels may result in predators becoming mismatched with prey availability, reducing fitness and potentially driving population declines. Such “trophic asynchrony” is hypothesized to have contributed to recent population declines of long‐distance migratory birds in particular. Using spatially extensive survey data from 1983 to 2010 to estimate variation in spring phenology from 280 plant and insect species and the egg‐laying phenology of 21 British songbird species, we explored the effects of trophic asynchrony on avian population trends and potential underlying demographic mechanisms. Species which advanced their laying dates least over the last three decades, and were therefore at greatest risk of asynchrony, exhibited the most negative population trends. We expressed asynchrony as the annual variation in bird phenology relative to spring phenology, and related asynchrony to annual avian productivity. In warmer springs, birds were more asynchronous, but productivity was only marginally reduced; long‐distance migrants, short‐distance migrants and resident bird species all exhibited effects of similar magnitude. Long‐term population, but not productivity, declines were greatest among those species whose annual productivity was most greatly reduced by asynchrony. This suggests that population change is not mechanistically driven by the negative effects of asynchrony on productivity. The apparent effects of asynchrony on population trends are therefore either more likely to be strongly expressed via other demographic pathways, or alternatively, are a surrogate for species' sensitivity to other environmental pressures which are the ultimate cause of decline. [ABSTRACT FROM AUTHOR]

Capsule:Across Britain, breeding Eurasian CurlewNumenius arquataare less numerous and have shown greater population declines in areas with more arable farming, woodland cover and higher generalist predator abundance. Aims:We present the first national-scale analysis of the potential drivers of Curlew population change in Britain, which is needed to guide conservation action for this globally near-threatened, declining species. Methods:Breeding Bird Survey data and environmental predictors were used to model variation in Curlew abundance in 1995–99 and 2007–11, and population change between these periods. Results:Arable farming and woodland cover were negatively associated with Curlew abundance and population declines. Curlew abundance was positively associated with extent of protected area coverage and gamebird numbers. Abundance and population change were positively associated with cooler temperatures and higher summer rainfall, but negatively associated with numbers of generalist predators. Conclusions:We found support for the negative effects of intensive agriculture, forestry, increases in generalist predator populations and climate warming on Curlew abundance and population change. Effective site protection and measures to reduce generalist predator abundance may be important conservation measures, together with improving breeding habitat quality in the wider countryside. [ABSTRACT FROM PUBLISHER]