A quest to hatch more endangered kākāpō eggs
Monday, 7 January 2019
It's a science problem that's less chicken - more parrot - and egg.
With a global population of just under 150, kākāpō eggs are precious. But only around half will go on to hatch into one of the endearing, flightless parrots.
Hatching failure is more common in endangered birds. As the population further dwindles, inbreeding becomes more common - and the lack of genetic diversity leads to even fewer kākāpō clutches hatching.
But now, in an almost $1 million programme, Otago University scientist Bruce Robertson hopes to break the destructive cycle by unlocking their DNA .
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'They are amazing, very charismatic. If you've met a kakapo you just sort of fall in love with them,' Robertson said. He's been studying the moss-green feathered birds, which have owl-like faces, for 23 years.
'You have to worry because once you get down to those sorts of numbers it is not just a genetic problem. There could be a catastrophe - a disease or something could wipe them all out.
'It is very precarious the situation they are in, so anything we can do to try and assist the recovery programme and potentially increase their numbers has to be a good thing.'
It's a grim task, but Robertson will analyse dead embryos transported back from the Kākāpō Recovery programme on three predator-free islands.
He'll work alongside the conservation genetics team San Diego Zoo, who breed the 'alala, or Hawaiian crow. It's now extinct in the wild and there are only 114 left in captivity, with a hatching failure of 60 per cent.
They'll compare the genomic architecture of eggs that have hatched and those that have failed, using whole genome sequences.
And it's hoped the research will lead to new breeding strategies to boost the chicks' chance of survival.
'We know in a lot of species of endangered birds that they show inbreeding depression so when there are small numbers of them and they start mating with relatives you end up getting this poor hatching success,' Robertson explained.
'The plan is to try and identify if there are certain genes that are involved. It might just be one gene, or 1-2 genes involved, but it also might be that there a whole bunch of little genes and it is a cumulative effect.
'Once we have figured that out, we then want to put in place breeding strategies which will then, hopefully, mitigate that effect and then we'll see more eggs hatching.'
Robertson received a $933,000 grant from the Royal Society's Marsden Fund to carry out the work.
The molecular ecologist has also worked on an ambitious programme to sequence the genomes of all living adult kākāpō.
The 'night parrot' population was abundant in New Zealand for thousands of years, but the arrival of European settlers and their predators almost wiped them out.
By the 1970s, only 18 males were known to exist in Fiordland. The species seemed doomed until more were discovered on Stewart Island in the 1980s.
The kākāpō is the world's heftiest parrot, with the males weighing in at up to 3.7 kg. And they can live to 90 years old.