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
Storrs L. Olson world's foremost paleornithologists. He was also the 1994 recipient of the Loye and Alden Miller Research Award. He was formerly curator of birds at the United States National Museum of Natural History; , he holds an emeritus position in the institution. Several prehistoric bird species have been named after Olson, including "Nycticorax olsoni", "Himantopus olsoni", "Puffinus olsoni", "Primobucco olsoni", "Gallirallus storrsolsoni", and "Quercypodargus olsoni". Storrs L. Olson Storrs Lovejoy Olson (born April 3, 1944) is an American biologist and ornithologist who spent his career the Smithsonian Institution, retiring in 2008. One of the world's foremost avian paleontologists, he is best