Christchurch's godwit numbers are looking healthy this year, despite food shortages during their migration.
Godwits travel 17,000km from the southern hemisphere to the north, and back every year. Photo: Wikimedia commons
Godwits fly from New Zealand to Alaska annually for their mating season.
Leaving New Zealand in March, thousands of godwits have made it to China's Yalu Jiang National Nature reserve as part of their journey.
However, an unusually cold winter has led to their food source being depleted, leading researchers to plant clams for the birds out of fear for their survival.
The godwits returned to the Southshore Spit in September with a stock take of the birds is currently underway - and the numbers look higher than the year before.
Christchurch City Council Park Ranger Andrew Crossland said there appears to be about 1500 birds.
"The number of godwits are slightly up, there were about 50 less last year," he said.
However, there will be a few stragglers still making their way to Christchurch until February, so their numbers won't be fully confirmed until then.
Despite numbers looking surprising healthy so far this season, Mr Crossland said numbers have continued to drop drastically over the last five years.
"They're still 500-700 birds lower to what they've been in the recent past, so we don't know completely what's happening yet this year, but we do expect numbers to rapidly decline as they lose that habitat in the Yellow Sea," he said.
Mr Crossland had recently travelled to Indonesia and observed shore birds that have altered their migration strategy to stop off in areas where there were rich food sources.
Godwits are known as creatures of habit, who take the same migration route every year. Mr Crossland still hoped maybe that would change.
"There are areas that lie under or near [the route] our New Zealand godwits take, for example the coastline of New Guinea, there's a lot of habitat there, so in theory there's potential for them to break the migration and use the habitat there," he said.
However, he said it was unlikely a lot of the birds would change their migration pattern in time and many of the birds will still die.