Birds are using anti-bird spikes to protect their nests, a Netherlands team has found

Transcript

A MARTÍNEZ, HOST:

OK, let's have a conversation about birds, angry birds.

LEILA FADEL, HOST:

Well, maybe angry birds is a bit too harsh.

MARTÍNEZ: (Laughter).

FADEL: Protective birds may be more fitting, although both sound scary to me. Seems birds are making their nests with hazards like metal and spikes.

AUKE-FLORIAN HIEMSTRA: The biggest nest we found, a nest that included more than 1,500 nasty, metal anti-bird spikes.

MARTÍNEZ: That's Auke-Florian Hiemstra. He's a biologist at the Naturalis Biodiversity Center in Leiden. He and his team visited the roof of a Belgian hospital that gave the birds what they needed to turn their nest into a bunker.

HIEMSTRA: There were a lot of bird spikes. But all the bird spikes closest to the nest, they were gone. And just a trail of glue was present.

FADEL: Hiemstra said some smart birds are using the stuff that humans use to shoo them away and instead are creating protective bowls over their heads.

HIEMSTRA: But, yeah, I think the magpie ripped them off the roof and used them in its own nest. We have examples of crows using them and examples of magpies using them. And so this is within the family of the corvids, and those are very smart birds.

MARTÍNEZ: And what exactly are these birds borrowing from the humans around them?

HIEMSTRA: Barbed wire, but also - and I think this is the funniest example - knitting needles.

MARTÍNEZ: OK, sounds extremely uncomfortable to live there.

FADEL: Right, let alone raise baby birds there. But Hiemstra says these nests may be more welcoming to bird families than you might think.

HIEMSTRA: So the whole outside of the nest is covered with these bird spikes. But within the nest, it's this very safe place made with soft material. So the young ones are safe. But I think, well, the parents may struggle a little bit to handle the material.

MARTÍNEZ: So maybe one of them smart birds can help me design my next home because one thing's for sure, you will not need locks if you got barbed wire.

(SOUNDBITE OF ARI PULKKINEN'S "ANGRY BIRDS THEME") Transcript provided by NPR, Copyright NPR.