Updated Fri at 6:41am
A species of threatened bird living on iconic islands off Western Australia's coast has become the lightest seabird in the world to ever be tracked, an ecologist says.
Small, waterproof GPS devices were fitted to 18 lesser noddy birds, a species that is only known to breed on three islands within the Houtman Abrolhos, a network of islands about 80 kilometres off the coast of Geraldton.
The birds weigh about 100 grams.
Data from the GPS devices revealed the threatened birds were travelling more than 100 kilometres from the islands, for up to 17 hours at a time, to gather food from unprotected waters.
Ecologist Chris Surman has studied the threatened seabirds for 25 years and said the data highlighted some of the birds' feeding zones.
"What we're hoping to do is build up a picture and find these vulnerable sorts of hot spots for these birds that are away from the islands," Dr Surman said.
"So when you do conservation work, you can easily target where the birds are breeding and look at what sort of habitats to set aside through conservation reserves."