Tiny dotterels' terrible year
When a tiny bird was born on a black gravel beach, it waited by the eggs that contained its siblings.
Within 24 hours, the bird was dead; its siblings, which hatched soon afterward, were killed the day after that, likely by predators.
That was the fate of one banded dotterel nest in Kaiko¯ura, part of a stronghold for a species at risk of extinction.
The gravel beach in South Bay is a perfect habitat for the dotterel where adults hide their nests in open spaces and defend them vigorously.
A good breeding season was expected after the earthquake, which created new habitat through coastal uplift and provided more food.
It has been a disastrous year thus far. Not one bird survived from 13 nests, which one researcher described as ‘‘a terrible result for the species’’.
On two occasions, people set bonfires almost directly on nests, likely unaware they were there. In another, a domestic house cat plundered two nests while roaming the beach.
Last season, a stoat caused much of the damage. A tsunami caused by the earthquake washed away a nest. Sometimes, a careless quad biker or a dog off its lead can destroy nests months in the making.
New Zealand’s banded dotterel population has been in long-term decline. Its numbers have dropped by about two-thirds in the past decade. The species was considered ‘‘in serious trouble,’’ according to a recent Parliamentary Commissioner for the Environment analysis, and is one of about one-third of New Zealand’s bird species deemed at risk of extinction.
Ailsa Howard, a researcher, has studied the Kaiko¯ura population as part of a five-year project. She said its alarmingly poor reproductive success did not bode well for the species.
‘‘It’s a species we know really well and it can’t continue to have such a tiny reproductive capacity. In the environment we have now, they just can’t breed. We’re seeing the numbers plummet. It seems silly to say species such as banded dotterel could become extinct, but it seems a very real possibility.’’
Banded dotterels used to be common throughout New Zealand, but have gradually disappeared from many places.
Predation was one major problem, Howard said. While they hid their nests from aerial predators, they were vulnerable to mammals such as stoats, cats, hedgehogs and humans.
People were a problem, usually due to naivety – she knew of locals who took their cat to the beach for a picnic, and others who rode quad bikes and let their dogs run free.
‘‘The birds themselves are discreet and camouflaged. People don’t see them,’’ Howard said. ‘‘I’d really like to see us market our beaches as either wild beaches or wildlife beaches, because they are. If you give them that name, it creates people’s expectations and behaviour.’’
Because dotterels re-nest, there is hope the Kaiko¯ura population’s breeding season will turn around – nine nests are in progress and one chick has since hatched.
There may be hope for the species as a whole, given how widely they’re dispersed and how they aggressively defend their nests, darting at predators such as dogs to protect their chicks.
If the trend continued, their numbers would go too low and it would be difficult to bring them back.
‘‘They’re very gutsy and very tough, but you can’t come back from being eaten. If a commitment was made, I think banded dotterels would have a very good chance. I’m hopeful for dotterels, but we haven’t got much time, because the job’s big.’’