Seaside Sparrows (Ammodramus maritimus) nest at varying population densities, and breeding pairs may occupy either large, all-purpose activity spaces or small nesting territories, foraging in undefended areas separate from the nest site. We determined the prevalence of extra-pair paternity in a large, socially monogamous population of Seaside Sparrows nesting in small, overlapping territories. ...

We appreciate notification of the error in Sykes et al. [1], where we matched mitochondrial 12S RNA sequence recovered from two ‘yeti’ hair samples found in Ladakh, India (no. 25025, .40 years old) and Bhutan (no. 25191 .10 years old) with GenBank accessions recovered from the jawbone of a Pleistocene polar bear Ursus maritimus described in Lindqvist et al. [2]. The matches were instead to a mo...

We observed a case of adoption of a single four-month-old polar bear cub (Ursus maritimus) into an existing litter of two cubs on Hopen Island, Svalbard. We believe the high density of maternity dens in the study area may increase the likelihood of natural adoption. Speculation about theoretical implications of adoption is of scientific interest. However, we believe that the probability of adop...

Polar bears (Ursus maritimus) and brown bears (Ursus arctos) are closely related species for which extensive mitochondrial and nuclear phylogenetic comparisons have been made. We used previously published genotype data for 8 microsatellite DNA loci from 930 brown bears in 19 populations and 473 polar bears in 16 populations to compare the population genetic relationships of extant populations o...