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
Cape Byron Marine Park identifies the migratory little tern "(Sterna albifrons)" and the Beach stone-curlew "(Esacus neglectus)" as endangered. Seabirds that utilize the Cape Byron Marine Park are the providence pretal "(Pterodroma solandri)", flesh-footed shearwater "(Puffinus carneipes)", and the masked booby "(Sula dactylatra)" which are protected under the National Parks and Wildlife Act 1974. Although no invertebrates have been identified as endangered or vulnerable, it is important to acknowledge that there are a plethora of invertebrates within the Cape Byron Marine Park which are critical to the health of the local ecosystems. These include a variety of molluscs such as the gold ring cowries