Natividad Island, where cats are in control

Natividad Island, or Isla Natividad, is an Island off the northwest coast of Mexico. A small fishing island, the population of less than 400, catch sea snails, lobster and clams.

Those are Wikipedia facts. Trust me though, effort did go into this!

When I was trying to figure out a response to today’s horribly difficult daily prompt (viable), I came across this article:

The effect of feral cats on the population viability of black-vented shearwaters (Puffinus opisthomelas) on Natividad Island, Mexico.

That’s going to be a great one for my SEO!

This is a research article, so it’s probably inaccessible to most. So here’s the story. Apparently, feral cats are well known for harming seabird colonies. On Natividad, a study investigated the effects of cat predation on the seabird populations. The cats have been the cause of multiple seabird extirpations and extinctions! (Internet says extirpations means destruction or elimination.)

Black-vented shearwater, the bird currently under threat. Photo courtesy of flickr.

The island has had a tumultuous relationship with cats. They were brought to the island around 1922 by the seasonal fisherman. For around 20 years, 1960-1980, the feral cat population almost disappeared. The Islanders couldn’t live without them, the ‘native deer mouse’ were everywhere. To control them they reintroduced cats.

The study concluded that the cats could eliminate a bird population of 150,000 within 20 years. Sounds horrendous? Are you picturing armies of cats slaughtering birds? In reality, they think there are only about 25 cats, and each eats 1.5 birds a day to survive.
So that’s not a lot, what’s the problem then? The cats focus on the young birds and eventually it leads to fewer and fewer birds.

Did they kill the 25 feral cats?

I’m sure there will be someone reading this wondering what they PROPOSE to do about it. It’s certainly what I was concerned about! They looked at other islands, some of which were in Scotland (yay!), and found the cats had a secondary food source. Rabbits. Though one study did find that rabbits increased the cat population…
And that was the unsatisfactory ending to their article.

I’m fascinated now to learn more about how people manage cat populations on islands. It’s never occurred to me before. Thank you daily prompt! (I am surprised to be saying that because trying to relate viable to cats is hard. Really hard.)

The cat photographs are courtesy of an article in The Atlantic about Aoshima Island, an island where there are more cats than people. Check it out, it’s a really interesting read. And, literally, hundreds of cats to look at.

 

Much love,
Annie, Will and the kitties
xxxxx

Response to the WordPress Daily Post one-word prompt: Viable