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
Diego Garcia Other nesting native birds include red-tailed tropicbirds ("Phaethon rubricauda"), wedge-tailed shearwaters ("Puffinus pacificus"), Audubon's shearwater ("Puffinus iherminierii"), black-naped terns ("Sterna sumatrana"), white (or fairy) terns ("Gygis alba"), striated herons ("Butorides striatus"), and white-breasted waterhens ("Amaurornis phoenicurus"). The 680-hectare Barton Point Nature Reserve was identified as an Important Bird Area for its large breeding colony of red-footed boobies. The island hosts introduced bird species from many regions, including cattle egrets ("Bubulcus ibis"), Indian barred ground dove, also called the zebra dove ("Geopelia striata"), turtle dove ("Nesoenas picturata"), Indian mynah ("Acridotheres tristis"), Madagascar fody ("Foudia madagascariensis"), and chickens ("Gallus gallus"). Currently, three