Godwits' ability to tell when to start their annual migration will be the focus of one of 86 projects that have won $54.6 million from the Marsden Fund this year.

Competition for Marsden Fund money remains intense, with a success rate of just 7.7 per cent.

From the 1113 preliminary proposals received, 229 project teams were asked to put in a full proposal, before that was whittled down to the successful bids.

Godwit researchers Phil Battley and Andrew Fidler , of Massey University and the Cawthron Institute respectively, have received $920,000 across three years for a genetic investigation of how bar-tailed godwits know when it is time to begin their 18,000-kilometre trek from New Zealand estuaries via the Yellow Sea to Alaskan breeding grounds.

The birds, which gather on the Avon-Heathcote Estuary and are Christchurch favourites, begin their annual migration about the second week of March and have left by the end of the first week of April.

Battley said there were godwits at hundreds of sites around New Zealand.

Birds that left first headed for breeding grounds in the Yukon delta, where the thaw set in about three weeks earlier than further north in Alaska.

"What's really obvious when you are in the estuary and the birds are in front of you, they do a whole lot of distinctive calling, jump around and flap their wings, recruiting others who want to go on migration," Battley said.

"Other birds have no interest in going, but might go tomorrow. So what makes it want to leave tomorrow or next week instead?

"If you take all birds from the Avon-Heathcote Estuary, they have identical conditions but are departing at different times, despite receiving the same external information. So whatever mechanisms they have for determining their departure date, it's an internal decision.

"Can we find differences in the internal clocks between birds that leave early and late in the migration?

"It's nice that Christchurch likes godwits as much as it does. They're pretty amazing birds."

Warmer springs in Alaska with climate change meant the optimum time for godwits to breed would get earlier. However, if their time of departure was fixed, they would increasingly get it wrong - arriving late at the breeding grounds, and their productivity would fall, Battley said.

Marsden Fund council chairwoman Juliet Gerrard said the money disbursed allowed New Zealand's best investigators to work on their most exciting ideas.

"In the long term we expect some of these projects to make a big difference to New Zealand in terms of economic growth, social issues and a wider understanding of who we are as New Zealanders," she said.

Other projects to be funded include:

❏ Groundwater effects from earthquakes.

❏ Kauri and climate change.

❏ Tidal power's future potential in New Zealand.

❏ Astronomical dark matter.

❏ Can things become invisible?

- © Fairfax NZ News