The first waves of bar-tailed godwits have arrived at the Avon Heathcote Estuary/Ihutai following their heroic annual migration from the northern artic.

Godwits take a 11,500km diagonal flyway across the central Pacific Ocean from the Alaskan coast directly to coastal habitats in Pegasus Bay and Banks Peninsula.

They do this in six to eight days non-stop and lose half their body weight in the process as they burn up fat reserves.

“The godwits arrival on Wednesday 11 September is a few days later than their 9 September arrival in 2023 and 7 September arrival in 2022,” says Andrew Crossland, Christchurch City Council Parks Ecologist.

“On Wednesday afternoon, 228 birds were counted. This was 56 more birds than the day before when Council staff confirmed that the over-wintering flock of 171 juveniles were present without any newcomers evident. More flocks arrived overnight and by Thursday noon, 441 birds were on the estuary."

More surges are expected over coming days as numbers build to 1000-1500 birds on the estuary by early November, with another 300-450 at Brooklands Lagoon, Lyttelton Harbour and Lake Ellesmere.

Migratory birds escaping the arctic winter don’t just come to New Zealand from Alaska, but also migrate over the western Pacific or pass over the east coast of the Asian Mainland, the Philippines and New Guinea.

Most of these birds are much smaller than godwits and fly as far as 15,000 km from breeding grounds in Siberia.

“This year the godwits were beaten by a Siberian species, the red knot, with two of these migrants reaching the estuary on Tuesday 10 September, increasing to five on Wednesday and six on Thursday,” Mr Crossland says.

“They’re about half the size of a godwit and are the second-most abundant Arctic migrant in New Zealand, with thousands flying to Northland and Farewell Spit in Golden Bay. Between 50-100 red knots are found in the Christchurch area each year, with most at Lake Ellesmere.”

People wishing to see the godwits are advised to view them from a distance to avoid disturbance and ensure dogs are kept well away.