Western jackdaw amounts of silicaceous and calcareous grit to aid digestion of vegetable food and supply dietary calcium. Opportunistic and highly adaptable, the western jackdaw varies its diet markedly depending on available food sources. They have been recorded taking eggs and nestlings from the nests of the skylark ("Alauda arvensis"), Manx shearwater ("Puffinus puffinus"), razorbill ("Alca torda"), common murre ("Uria aalge"), grey heron ("Ardea cinerea"), rock pigeon ("Columba livia"), and Eurasian collared dove ("Streptopelia decaocto"). A field study of a large city dump on the outskirts of León in northwestern Spain showed that western jackdaws forage there in the early morning and
Audubon's shearwater likely, as yet another synonym of "dichrous". The case of the more distinct "bannermani", the range of which is parapatric to that of the Pacific "dichrous", is more complicated. It has for some time been proposed as a distinct species, Bannerman's shearwater ("P. bannermani"). In the absence of more recent data to investigate this claim, its status continues to be altogether unresolved, though the case for it being at least a distinct subspecies in the "bailloni" clade seems good. Audubon's shearwater The Audubon's shearwater ("Puffinus lherminieri") is a common tropical seabird in the petrel family. Sometimes known as the dusky-backed