Keith A. Hobson

TL;DR: In this article, the authors compared modern and pre-industrial teeth of Belugas (Delphinapterus leucas) and walrus (Odobenus rosmarus rossmarus) at sites in the Canadian Arctic so that the relative amounts of natural and anthropogenic Hg in modern animals could be estimated.

TL;DR: SigmaPCBs, DDTs, HCHs and toxaphenes seem to be at similar levels in West Greenland and Arctic Canada, which can be explained by the close winter distributions of populations as well as large ranges in concentrations, time span, number of analyses and the size/age composition of the data.

TL;DR: A recent evolutionary history for this species is revealed that differs from that of most other widespread North American passerines and evidence for limited gene flow in a species with potentially large dispersal distances is provided.

TL;DR: In this paper, the authors evaluated the effects of winter habitat occupancy, as inferred from tissue stable-carbon (δ13C) and -nitrogen(δ15N) isotope values, on nutritional condition and arrival date of seven long-distance Nearctic-Neotropical migratory species sampled at Delta Marsh Bird Observatory (DMBO, Manitoba, Canada) during their spring migration to more northerly breeding areas.

TL;DR: Stable isotope analyses were used to identify the strategy of nutrient acquisition and allocation used by females to meet the demands of egg production and found that Harlequin Ducks relied on food available in streams on breeding grounds for egg formation, and reserves stored on marine areas were likely used during other energetically and nutritionally demanding periods.