(ORDO NEWS) — About a hundred years ago, house mice were inadvertently introduced to a tiny island off the west coast of North America, and now about 50,000 voracious rodents live on a piece of land about two football fields.
By studying their diet, scientists were able to assess the impact of mice on the island ecosystem and decide on their future fate.
In the late 19th and early 20th centuries, house mice accidentally ended up on the rocky Southeast Island in the Farallon Islands off the coast of California.
Since then, the islands themselves have managed to declare the National Wildlife Refuge , and the rodent population on them has grown incredibly, reaching at least 50 thousand individuals.
Naturally, a tiny piece of land is not able to feed such a horde only at the expense of plant resources, and mice, being easily adaptable rodents, readily switched to animal food.
The scientists studied the dynamics of the island population of mice over 17 years and analyzed the composition of stable carbon isotopes in the tissues of the animals. This was necessary to determine the diet of rodents.
As a result, they concluded that the number and diet of mice change dramatically during the year from almost completely vegetarian in the spring, when the population is at a minimum, to mixed feeds in the summer and eating insects in the fall, when the island is already teeming with rodents.
Not only do mice leave the endemic Farallon salamanders hungry by eating a huge amount of insects, their presence also attracts predators, such as burrowing owls , to the islands.
There is no data yet whether rodents pose a danger to the local colony of seabirds, but judging by the situation on other sea islands “infected” with mice, voracious animals can not only eat corpses, but also destroy nests and kill chicks.
Now that scientists have a complete understanding of the diet of mice in the Farallon Islands and how much their population has grown, conservationists must take the next step: to destroy the island rodents and return the ecosystem of the islands to its original state.
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