Sun compass in animals internal clock to determine their heading, and that they had learnt the actual direction down to the sea on their particular beach. Lockley's experiments with Manx shearwaters ("Puffinus puffinus") showed that when released "under a clear sky" far from their nests (in Skokholm), the seabirds first oriented themselves and then "flew off in a direct line for Skokholm", making the journey rapidly. For example, one of the birds, released at Boston airport, arrived in Skokholm 12½ days later; Lockley calculated that if the birds flew for 12 hours per day, they must have travelled at 20 miles per hour, their
Great shearwater Great shearwater The great shearwater ("Ardenna gravis"; formerly "Puffinus gravis") is a large shearwater in the seabird family Procellariidae. "Ardenna" was first used to refer to a seabird by Italian naturalist Ulisse Aldrovandi in 1603, and "gravis" is Latin for "heavy". The great shearwater's relationships are unclear. It belongs in the group of large species that have been separated as genus "Ardenna" (Penhallurick & Wink 2004); within these, it might be allied with the other black-billed, blunt-tailed species, the short-tailed shearwater and especially the sooty shearwater (Austin 1996, Heidrich "et al." 1998). Alternatively (Austin 1996, Austin "et al." 2004), it