Birds Aiding Navigation

Observations of birds migrating to south from Micronesia and Polynesia in Spring would have been commonplace and navigators would have been aware of their departure in spring and return in autumn. 

The Shining cuckoos (Chrysococcyx lucidus)

The Shining cuckoos (Chrysococcyx lucidus) breed in Australia, Vanuatu and New Caledonia as well as New Zealand. These Cuckoos head north in Autumn to the Bismarck Archipelago and Solomon Islands, and return to New Zealand from late September. Once they have mated and laid their olive-green eggs in grey warbler’s nests (one egg per nest), they are free of parental duties, but stay around for several months.

The Longtailed Cuckoo (Eudyamys taitensis)
The Longtailed Cuckoo (Eudyamys taitensis) has its main winter range from Palau (134.5°E) in the west to Henderson Island (128.3°W) in the east and its annual migration south takes place in September and October. The breeding sites are spread the whole length of the country in nests pilfered from whiteheads, yellowheads or brown creepers.

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The Bar-tailed godwit (Limosa lapponica)

The Bar-tailed godwit (Limosa lapponica) leave from Alaska in the northern autumn and fly non-stop in a direct route south across the central Pacific to New Zealand taking 7–9 days, from September to mid-October. As they fly at heights between 1500 to 5000 meters sightings would be difficult. The migration flight of the Godwit south may have been seen in the middle Pacific, the small birds flying in a large V-shape convoy.  However studies of the migration route indicates that the birds fly starting at about 150 East in Alaska and travel south moving slowly west crossing over Fiji close to the 180 longitude line.

Voyagers reaching the Kermadecs might have seen them if they were sailing in September and October, but most voyages probably started in November at the earliest.

 Thus most of the migratory birds are not flying around in the voyaging months. Nevertheless the navigators may have worked out a star path route to travel if they could follow the birds.