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
Persian shearwater Persian shearwater The Persian shearwater ("Puffinus persicus") is a seabird in the family Procellariidae formerly lumped in with Audubon's shearwater ("Puffinus lherminieri"). There are two listed subspecies of the Persian shearwater: After breeding, the northern subspecies ranges from the southern Red Sea, the Gulf of Aden and the Somali coast across the south of the Arabian Peninsula to the Gulf of Oman, Pakistan and western India. The southern subspecies stays in the area around the Comoros and the Tanzanian and northern Mozambican coast. The nominate subspecies is thought to number in the thousands of pairs on the Khuriya Muriya Islands