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
Tropical shearwater subspecies thought to number 3,000–5,000 pairs on Réunion and fewer than 100 individuals on Europa (reviewed by Brooke 2004), though it is thought there are many more breeding colonies on other islands in the Pacific. The population seems to be stable. Tropical shearwater The tropical shearwater ("Puffinus bailloni") is a seabird in the family Procellariidae formerly considered conspecific with Audubon's shearwater ("Puffinus lherminieri"). There are five listed subspecies of the tropical shearwater: The tropical shearwater is found in the tropical parts of the western Indian Ocean from east Africa to southern India and in similar regions of the Pacific from