Bird watchers throughout New Zealand are beginning an annual count of threatened species of migratory shore birds.
The Ornithological Society expects up to 150 people to take part in the survey at a dozen sites from Northland to Southland.
The survey starts on Friday.
A spokesperson Rob Schuckard says godwit, red knot and ruddy turnstone birds spend up to six months in New Zealand before flying to breeding grounds from Siberia to Alaska.
Mr Schuckard says reclamation means there is less food available for the migrating birds.
He says there is concern about the number of red knots, because their halfway staging point in the Yellow Sea is being industrialised.