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
Audubon's shearwater homogeneous north-western Indian Ocean range, but not in the ecologically more diverse and by far larger Pacific range of "dichrous". These unresolved problems notwithstanding, this clade – possibly including the preceding one – has been proposed to constitute a separate species, the tropical shearwater or Baillon's shearwater, "Puffinus bailloni". These taxa could not be included in the most recent studies due to lack of material. The case of "gunax" seems fairly straightforward – as certainly as this can possibly be said in the absence of new data, it belongs to the "bailloni" clade either as a distinct subspecies, or, more