Aggregative responses of marine predators to a pulsed resource.

Pulsed resources resulting from animal migrations represent important, transient influxes of high resource availability into recipient communities. The ability of predators to respond and exploit these large increases in background resource availability, however, may be constrained when the timing and magnitude of the resource pulse vary across years. In coastal Newfoundland, Canada, we studied aggregative responses of multiple seabird predators to the annual inshore pulse of a key forage fish species, capelin (Mallotus villosus).

Different individual-level responses of great black-backed gulls (Larus marinus) to shifting local prey availability.

To grow, survive and reproduce under anthropogenic-induced changes, individuals must respond quickly and favourably to the surrounding environment. A species that feeds on a wide variety of prey types (i.e.

Allopatric humpback whales of differing generations share call types between foraging and wintering grounds.

Humpback whales (Megaptera novaeangliae) are a cosmopolitan baleen whale species with geographically isolated lineages. Despite last sharing an ancestor ~ 2-3 million years ago, Atlantic and Pacific foraging populations share five call types. Whether these call types are also shared between allopatric breeding and foraging populations is unclear, but would provide further evidence that some call types are ubiquitous and fixed.

Isotopic Discrimination (δN, δC) in Captive and Wild Common Murres () and Atlantic Puffins ().

Studying the diet of consumers using stable isotopes provides insight into the foraging ecology of individuals and species. To accurately reconstruct the integrated diet of animals using stable isotope values, we must quantify diet-tissue discrimination factors (DTDFs), or the way in which stable isotopes in prey are incorporated into the tissues of consumers. To quantify DTDFs, controlled experiments are needed, whereby consumers are fed a constant diet.

Diet-tissue discrimination factors (δ N and δ C values) for blood components in Magellanic (Spheniscus magellanicus) and southern rockhopper (Eudyptes chrysocome) penguins.

Rationale: Analysis of the stable isotope ratios of carbon and nitrogen (δ C and δ N values) is increasingly being used to gain insight into predator trophic ecology, which requires accurate diet-tissue discrimination factors (DTDFs), or the isotopic difference between prey and predator. Accurate DTDFs must be calculated from predators consuming an isotopically constant diet over time in controlled feeding experiments, but these studies have received little attention to date, especially among seabird species.

Methods: In this study, aquarium-housed Magellanic (Spheniscus magellanicus) and southern rockhopper (Eudyptes chrysocome) penguins were fed a single-prey source diet (capelin Mallotus villosus) for eight weeks.

Egg cannibalism in capelin Mallotus villosus at beach and deep-water spawning habitats in the north-west Atlantic Ocean.

We investigated egg cannibalism in spawning capelin Mallotus villosus on the north-east Newfoundland coast during July 2012-2014, specifically whether sex, spawning condition (i.e., spawning or spent) and spawning habitat influenced egg cannibalism.

High flight costs, but low dive costs, in auks support the biomechanical hypothesis for flightlessness in penguins.

Flight is a key adaptive trait. Despite its advantages, flight has been lost in several groups of birds, notably among seabirds, where flightlessness has evolved independently in at least five lineages. One hypothesis for the loss of flight among seabirds is that animals moving between different media face tradeoffs between maximizing function in one medium relative to the other.

Individual specialization in diet by a generalist marine predator reflects specialization in foraging behaviour.

1. We studied chick diet in a known-age, sexed population of a long-lived seabird, the Brünnich's guillemot (Uria lomvia), over 15 years (N = 136; 1993-2007) and attached time-depth-temperature recorders to examine foraging behaviour in multiple years (N = 36; 2004-07). 2.

Effects of gill-net fishing on marine birds in a biological hotspot in the northwest Atlantic.

Marine biological hotspots, or areas where high abundances of species overlap in space and time, are ecologically important areas because energy flow through marine food webs, a key ecosystem process, is maximized in these areas. I investigated whether top predators aggregated at persistent spawning sites of a key forage fish species, capelin (Mallotus villosus), on the NE coast of Newfoundland during July and August 2000-2003. By examining the distributional patterns of top predators through ship-based surveys at multiple spatial and temporal scales, I found that the biomasses of birds-dominated by Common Murres (Uria aalge)-and mammals-dominated by whale species-were concentrated along the coast, with a biological hotspot forming near two persistent spawning sites of capelin in all years.

Seabirds at risk around offshore oil platforms in the north-west Atlantic.

Seabirds aggregate around oil drilling platforms and rigs in above average numbers due to night lighting, flaring, food and other visual cues. Bird mortality has been documented due to impact on the structure, oiling and incineration by the flare. The environmental circumstances for offshore hydrocarbon development in North-west Atlantic are unique because of the harsh climate, cold waters and because enormous seabird concentrations inhabit and move through the Grand Banks in autumn (storm-petrels, Oceanodroma spp), winter (dovekies, Alle alle, murres, Uria spp), spring and summer (shearwaters, Puffinus spp).

Differences in prey selection and behaviour during self-feeding and chick provisioning in rhinoceros auklets.

We determined whether a marine diving bird, the rhinoceros auklet, Cerorhinca monocerata, used different foraging behaviour and collected different prey items for its young than when feeding itself. Foraging behaviour was determined by conducting visual scans, and prey items were sampled by collecting fish delivered to chicks and by collecting fish where auklets were self-feeding, which was verified by two other sources of information. Adult auklets ate small fish (59.