Why have you never seen birds eating worms on the sidewalk? | science | news | the sun

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“While walking in the woods, I saw large nests of caterpillars in groups in the trees and wondered why the birds had not devoured them. However, they looked like easy prey, almost all you can eat at the buffet!” asks Benoit Lantiere, from Quebec.

exist Five types of butterflies in Quebec, all “at night”, whose larvae make “tents” – they are called “tent larvae” – where they shelter in groups during the night, and come out to feed on leaves during the day. Seeing these seemingly intact tents, it is tempting to think that these caterpillars have few or no predators, but this is a false impression.

“Blackbirds eat them, and blackbirds and cardinals are also good consumers of larvae. In fact, there are about sixty species of birds that feed on them. (…) But the specialized species is the black-billed cuckoo,” says Mr. Jennet.

in one Article review Researchers at the University of Minnesota, a predator and parasite of tent caterpillars, note that most birds only eat the small caterpillars and seem to give up the larger ones, whose hairs and spines are hard to digest. But cuckoos are able to accumulate these whiskers in their stomachs and spit them out into little balls, allowing them to feed on caterpillars of all sizes.

In fact, cuckoos are so specialized that they seem to follow the hatching of these larvae from year to year, only to establish themselves in places where they are abundant. “I remember there was a huge outbreak of American tent caterpillars [une des chenilles à tente du Québec] In Abitibi two years ago, says Mr. Jeanette. When I got there I asked people why the trees were still leafless even though it was June, and it was because there were so many caterpillars they all removed their leaves. I have also been able to notice and hear many cuckoos, which are usually a very discreet bird. I haven’t seen much before.”