“It suggests the behavior could be hereditary, but it could also be other things such as learning or cultural transmission of behavior,” said Kiyoko Gotanda, a zoologist at the University of Cambridge.
Humans settled on the Galapagos archipelago, famed for its rich biodiversity that inspired Charles Darwin’s theory of evolution, in the early 19th century. Apart from cats, settlers also introduced invasive species like rats, dogs, and pigs — which spelled trouble for small native island animals.
These animals, including birds and reptiles, displayed little anti-predator behavior back then because they had never seen these new predators before — they were only used to local predators like owls.
When Darwin visited the islands, which lie 621 miles (1,000 kilometers) from Ecuador, in 1835, he famously got close enough to throw his hat over the birds because they were so unused to humans they didn’t see him as a potential threat.
But this “evolutionary naivete” also meant the finches were easily hunted and targeted by the new predators, raising concerns for the biodiversity of the islands, said the study.
The finches eventually did develop anti-predator behavior, learning to fly away when a potential threat approached. And the threat was also lessened over the years — conservation efforts have seen invasive predators cleared and eradicated from four of the archipelago’s 19 islands.
It’s been a decade since the cats have been gone, but the finches still act like the threat is there.
Gotanda visited two islands that had gotten rid of invasive predators and “pristine” islands where predators hadn’t been introduced.
When she mimicked the approach of a predator, finches on the cleared islands flew away at a much greater distance than those on “pristine” islands — suggesting a difference in inherited anti-predatory behavior.
This heightened survival instinct may now threaten population recovery efforts, the study warned.
“The time and energy finches spend spooking themselves by fleeing when they are not in danger could be better spent looking for food, mating, laying eggs, and rearing their young,” said the press release.
The Galapagos were declared a national park in 1959 and a UNESCO World Heritage Site in 1978.