Strikingly, Dr Alex Bond, a conservation biologist and expert on marine birds from London's Natural History Museum, told IFLScience that this incident isn’t isolated – and worse has been seen elsewhere.
“On Gough Island, Tristan da Cunha, mice eat Tristan albatross chicks alive,” Bond added, something that’s been studied and documented. “The same is happening on subantarctic Marion Island,” where it appears mice are essentially scalping their prey.
“So rather than ‘blood-sucking’ mice, this is part of their routine predation.”
This incident is initially reminiscent of the behavior of another bloodthirsty critter, this time found on the Galapagos Islands: the so-called vampire finch. Found on the barren, dry Wolf Island, this bird sometimes survives by stabbing the oil gland-rich tail end of booby chicks until blood is drawn, which is used to quench their considerable thirst.
Is the behavior of these Midway mice, then, somewhat similar? It’s possible. An ecologist, speaking to the Washington Post, suggests that during full-blown droughts, mice were seeking hydration through any means possible.
Bond suggests that a direct comparison isn’t possible though, with these finches or other similarly behaving birds, like oxpeckers in Africa.
Unlike the newly invasive mice on Midway, “these all concern native species, where such predation has either evolved naturally, or has existed for centuries or millennia as predator and prey adapt in a sort of evolutionary arms race.”
Having lived largely free of rodents since they’ve been nesting there, seabirds on Midway Atoll are clearly unequipped to deal with mice. Not only do they instinctively not fear them, but they don’t possess any defense mechanisms that can help them out.
Nesting albatrosses are particularly vulnerable, as they’ll refuse to evade the mice and will instead stay put and guard their young.
Worryingly, the reproductive cycle of albatrosses is far slower than that of mice. Far from just meaning that mice are quickly going to outnumber their victims here, this also means that any losses they suffer from such attacks will have knock-on effects for their population for generations to come.
It’s not surprising, then, that the FWS is now planning to remove the mice from the island, although the debate as to how best to do this is still underway.