Perhaps the best-known and least understood voyagers are the Polynesian sailors of old. They are said to have used the stars and their knowledge of currents etc. and the flight of birds. Wiki says
One theory is that they would have taken a frigatebird (Fregata) with them. These birds refuse to land on the water as their feathers will become waterlogged making it impossible to fly. When the voyagers thought they were close to land they may have released the bird, which would either fly towards land or else return to the canoe
Frigate birds are black with long red necks and forked tails, easily recognised. Their ability to fly long distances is phenomenal.
The five extant species are classified in a single genus, Fregata. All have predominantly black plumage, long, deeply forked tails and long hooked bills. Females have white underbellies and males have a distinctive red gular pouch, which they inflate during the breeding season to attract females. Their wings are long and pointed and can span up to 2.3 metres (7.5 ft), the largest wing area to body weight ratio of any bird.
Able to soar for weeks on wind currents, frigatebirds spend most of the day in flight hunting for food, and roost on trees or cliffs at night.
So they need to be attached to land. The two main species are Christmas Island and Ascension.
Frigate bird fossils are classified as freshwater species. This is also true of corvids apart from cormorants or 'sea-ravens' which surprisingly are put in the same family as frigates by the bird experts.
The Fregatidae are a sister group to Suloidea which consists of cormorants, darters, gannets, and boobies.
Darters are also called snake birds presumably on account of their long necks.
As with frigate birds, an oddity of cormorants is their feathers aren't waterproof, surely a disadvantage for a bird that dives for fish for its living. But there seem to be two main categories of cormorant, the 'continental' and the 'Atlantic' sub-genres. The former live and feed inland unlike their smaller, Atlantic cousins. Quite strikingly different life styles in fact.
The classification system went a bit awry during the eighteenth and nineteenth centuries
Frigatebirds were grouped with cormorants, and sulids (gannets and boobies) as well as pelicans in the genus Pelecanus by Linnaeus in 1758 in the tenth edition of his Systema Naturae. He described the distinguishing characteristics as a straight bill hooked at the tip, linear nostrils, a bare face, and fully webbed feet....
...Martyn Kennedy and colleagues derived a cladogram based on behavioural characteristics of the traditional Pelecaniformes, calculating the frigatebirds to be more divergent than pelicans from a core group of gannets, darters and cormorants, and tropicbirds the most distant lineage.[14] The classification of this group as the traditional Pelecaniformes, united by feet that are totipalmate (with all four toes linked by webbing) and the presence of a gular pouch, persisted until the early 1990s.[15] The DNA–DNA hybridization studies of Charles Sibley and Jon Edward Ahlquist placed the frigatebirds in a lineage with penguins, loons, petrels and albatrosses
Cormorants are not sociable but do set up colonies in locations offshore not easily reached by sailors, such as the reefs of the Chausey islands (one of the most dangerous sections of the Channel). Unlike land-based corvids they don't caw but make a grunting sound described as 'the oinking of pigs'
[in Greek myth Odysseus's men were turned into pigs by Circe the sorceress and eventually rescued by Hermes who is in turn linked to the underworld, geese, swans, alphabet, travel, etc. Odysseus stayed on the island for a year which is suitably cyclical.]