Vocalization surveys conducted in Penny Strait, Northwest Territories, indicated that before ice break-up, bearded seals (Erignathus barbatus) preferred regions of less stable ice where break-up occurred early and avoided stable, landfast ice or areas heavily used by walruses (Odobenus rosmarus). Water depth did not appear to influence distribution. Numbers of calls increased between mid-April and early June, probably because of an increase in rate of calling by individual seals. Vocalization surveys can be used to separate preferred habitats from unsuitable ones. Using a single hydrophone and our current understanding of bearded seal vocal behaviour, it is not possible to determine the absolute number of bearded seals at or near a site using vocalizations. However, it is possible to measure the relative abundance of seals for spatial and temporal comparisons.
Factors affecting the winter distribution of wildfowl in the valley of the Ticino River (northern Italy)
