Hopes high for little blues’ breeding season this year

ANOTHER successful breeding season is all but in the books for Oamaru’s little blue penguins and the number of birds breeding at Oamaru’s former quarry site at Cape Wanbrow is expected to reach a record high next year.

Breeding birds at the Oamaru Blue Penguin Colony peaked in 2014, at 374, before a severe winter storm in 2015 wiped out many of them, colony research scientist Dr Philippa Agnew said.

However, with 366 breeders at the colony this year, the secondhighest yet, and the colony averaging a 9% growth over the long term, next season the number of the world’s smallest pen guin at the Tourism Waitaki-managed colony should top the total before the storm hit.

The year of the storm, adult birds experienced a 25% higher mortality than other years. Dr Agnew said adult survival normally averaged 85% and in 2015 it dropped to 60%.

Nearly 150 fewer breedingage birds began the breeding season.

Since the storm, a large influx of birds from outside the colony, higher than average juvenile survival rates in the past three years, and high adult survival rates could have all influenced the rebound of numbers, she said.

Across Oamaru Harbour at the Oamaru Creek penguin colony reserve, numbers had not bounced back as quickly.

In 2013, the number of breeders at each colony was the same, Dr Agnew said. In 2014, at the creek colony there were 331 breeding birds.

There were 231 breeding penguins there this year, an increase from last year and the year before, but still 100 birds short of the previous best.

However, the birds that did breed were successful, as 77% of all eggs laid resulted in a fledged chick, and the chicks fledged at healthy weights.

Staff were optimistic about an increase next year, as the Waitaki District Council had completed its coastal erosion protection work at the beach and a new fence was installed, better protecting the birds from dog attacks and human disturbance.

The 366 breeding birds at the quarry colony laid 513 eggs, which produced 413 chicks and to date, with just five chicks left ashore ready to fledge last week, 365 chicks successfully fledged.

About 71% of eggs laid had resulted in a fledged chick, and the longterm average at the colony was 69%, ‘‘so we’re happy with the way this season has gone’’, Dr Agnew said.

While many of the juvenile birds could be expected to survive and return to the colony for next year, little blue penguins start breeding at 2 or 3 years old so it would not be this year’s juveniles that influenced next year’s number of breeding birds.

The proportion of chicks staff expected to later return to breed was only about 19%.