Globally invasive species?

[DrDeth]

@Whack-a-Mole

Almost all invasive species were brought by humans. I recall a story of a cat owned by a man working in a lighthouse in New Zealand that made a species of bird extinct (his cat killed the last ones).

Sorta.

Lyall's wren

Lyall’s wren or the Stephens Island wren (Traversia lyalli ) was a small, extinct, flightless passerine belonging to the family Acanthisittidae, the New Zealand wrens. It was once found throughout New Zealand, but when it came to the attention of scientists in 1894, its last refuge was Stephens Island in Cook Strait. Often claimed to be a species driven extinct by a single creature (a lighthouse keeper’s cat named Tibbles), the wren in fact fell victim to the island’s numerous feral cats.[a][2] The wren was described almost simultaneously by both Walter Rothschild and Walter Buller. It became extinct shortly after.

And there are cats nearly everywhere, before the house cat was introduced. Several can interbreed with Felis Cattus, the Asian Leoprad cat being a solid example. And in fact the ALC fills the same niche, living close to humans and feasting on the rodents that humans have living alongside.

@Mangetout

Rats might be an example of universally invasive species, but only because we tend to regard them as unwanted in any and every place we see them.

Yeah the Norway Rat is pretty much a universal invasive species. Likely responsible for the extinction of several birds, such as the dodo ( pigs helped).

@silenus

This. Mine never go outside for the very reasons you named. They are all rescues as well.

Same here, altho one gets walkies on a leash in the backyard once in a while.

@Darren_Garrison

Domestic cats fill niches once taken up by predators that we have displaced. Far fewer mountain lions, foxes, wolves, eagles, etc than there used to be.

Right. Not to mention bobcats- I have heard of rancher who shot and poisoned them to protect their cattle! . The coyote is pushing back, along with the raven, and the falcon, they are adapting to live with humans. The cat just did it earlier. Feral cats are not much of a issue in true wilderness, since they have competition and predators- sure the coyote would rather eat a nice squirrel or a rabbit, but if mister “eatus anythingus” gets hungry they with cheerfully chow down on a cat. Around here people are told to not let their cats out as the coyotes do just that, but the idiots still do.

Housecats live in urban environments, they go where the people are, and so do rats, etc.

@Ulfreida

None of the large predators you name ate songbirds for a living.

Yeah but bobcats, weasels, etc do- small predators, and we have pushed them out, so the domesticated cat moved it.

@LSLGuy

Then of course we exterminate the hunting lobby.

At least in the recent past the hunting lobby has done more to protect the environment than Eco-groups have. Waterfowlers protect wetlands for example.

@dtilque

Earthworms are likely another invasive species everywhere. Well, except where it’s native to, of course. They’re certainly not native to the Americas, for example.

Nor are honeybees. But both species are general beneficial.

[Ulfreida]

@DrDeth

Nor are honeybees. But both species are general beneficial.

Honeybees are not beneficial except to humans, as it turns out. They are one of the factors in the decline of native bees and other pollinators.
Scientific American article

[dtilque]

Invasive earthworms are also not necessarily beneficial. They apparently help invasive plants take over the understory of forests:

Earthworm Invaders

[Whack-a-Mole]

@DrDeth

And there are cats nearly everywhere, before the house cat was introduced.

But I do not think cats were where Lyall’s Wren was. That’s why they were so easily finished off by one tabby. When just one appeared they had no evolved defense.

[md-2000]

Farley Mowat’s Sea of Slaughter describes the ecological decline of the Gulf of St. Lawrence area, and some of North America in general. He mentions how sailors from areas like Boston would put ashore on bird islands (isolated rocks full of seabird nests) and take the eggs for sale back home. (Typical tactic - go ashore and stomp all the eggs. Come back a while later to a full crop of fresh eggs not yet developing into chicks.) Quite often cats or rats would get ashore with the sailors, and the next year the sailors would find an empty island, all the chicks had been eaten (especially with rats) and the birds scared off.

Cats allegedly “domesticated” themselves when humans began farming (as the cartoon above points out). The bolder ones would hunt rats in the grainaries, and humans learned not to disturb them. The ones that thrived were those less skittish of humans. I’m sure in the process there was a level of symbiosis - the cat keeps my feet warm, and I keep the cat warm. The cat disposes of some table scraps that otherwise attract less savory feeders. As humans and agriculture moved into less tropical climates, cats could take advantage of warmer human habitats than the outside environment.

Because of their lesser domestication and the ubiquity of candidate small prey, cats have less problem going feral.

[Two_Many_Cats2]

Pope Gregory IX issued an edict connecting cats with Satanism and witchcraft, so cats and their owners were hunted down and slaughtered.

Then the rats came with their fleas bringing the Black Death…

What Leaper recently read is pseudo-scientific cat bashing bullshit.

[DrDeth]

@Whack-a-Mole

But I do not think cats were where Lyall’s Wren was. That’s why they were so easily finished off by one tabby. When just one appeared they had no evolved defense.

Well, no. First of all, it was once common throughout NZ, but introduced Polynesian rats ate the eggs. It’s last refuge was Stephens Island, when it was eliminated not by one tabby but by feral cats.

Much of what is commonly assumed to be established knowledge about this species’ extinction is either wrong or has been misinterpreted, starting with the account by Rothschild (1905) who claimed that a single cat had killed all of the birds.[1

But yeah, this has been the sad story of island based flightless birds everywhere,