By Sammy Westfall
Little blue penguins - the world's smallest penguin species, also known as fairy penguins or korora - are about a foot tall and weigh about two pounds. Their feathers are pale blue, even indigo, and they love to eat tiny fish such as anchovies and sardines. They're small but noisy.
Hundreds of these little birds are washing up, dead, on New Zealand shores, shocking residents walking along beaches and worrying experts about the implications of what so many deaths could mean.
"On the first day 75 dead penguins over a distance of 10 kilometers. And then Day 2, walking north, counted them again. That morning I counted 71," resident Vaughn Turner told local public broadcaster RNZ. "The third day, I counted about 59 dead birds."
The die-offs are not completely unusual, according to New Zealand's Department of Conservation. Every year, starting around November, members of the species wash up on shores, dead, sick or injured. "Some level of mortality is natural and to be expected," the department wrote in a report last year.
Still, the abundant deaths are leading scientists and conservation experts to ask: How much is normal? And, will it get worse?
Mass die-offs of the penguins - meaning 1 000 or more washed up - used to be a "once in a decade" event, the department said. In 1974, for example, 4 737 penguins washed up, and 11 years later, 5 386 did.
But climate change is probably making it a lot worse for the penguins as sea surface temperatures increase and marine heat waves and storms become more frequent.
"We may expect to see a corresponding increase in the amount of mass die-offs of penguin and other sea creatures," said the department report.
Climate change brings warmer waters, forcing the penguins to venture into colder, deeper waters for foraging. That change can make it harder for little penguins to nest, breed and find food, the department said. They starve, fall ill on top of stress and exhaustion and are more vulnerable to predators in the deep waters. Some young chicks who leave their parents cannot fend for themselves.
Less than a third of all chicks typically survive to adulthood, based on studies in the South Island of New Zealand.
The Department of Conservation's Graeme Taylor said that tests of some dead korora indicated starvation and hypothermia - especially in baby penguins that have neither the strength nor the endurance to search for food in deep ocean waters.
Elevated temperatures also make their food supply more sparse, Taylor said.
"In the past, you might have had a lot of good years followed by one bad year where a lot of birds die, but then they rebound in those good years," Taylor told the outlet. "But if we start to see the balance tipping towards more bad years versus good years, then they're just not going to be able to recover."
While the penguins were once common on the mainland coast, now they are largely found on more-remote islands - far from threats and disturbances from humans, dogs and introduced predators.
Environmentalists for more than a year have protested a construction zone at a marina development on Waiheke Island, off the coast of Auckland in northern New Zealand, which they said was disturbing korora habitats.