A wasp nibbled a baby bird for breakfast

A wasp’s bite may be as bad as its sting. A new video caught a wasp on camera, attacking and killing a baby bird in its nest.

The wasp was a paper wasp (Agelaia pallipes). Researchers caught the killing while filming bird nests in Florestal, Brazil. The scientists were studying the parental behavior of lined seedeaters (Sporophila lineola). These are small birds with short, stubby bills. They live in South America.

“It was totally unexpected,” says Sjoerd Frankhuizen. He’s a zoologist — someone who studies animals — at Wageningen University & Research in the Netherlands. He and his team saw a wounded baby bird in one of the nests they were studying. At first, the researchers suspected a reptile, larger bird or maybe ants. Ants made sense since they might leave the body behind. “We really had no idea that it would be a wasp,” Frankhuizen says.

Video of the nest shows the wasp landing on the 4-day-old seedeater’s head. While the nestling’s parents were away, the wasp bit the bird over and over. It also tore at its flesh. The lone attacker made 17 visits during the roughly hour and 40 minutes of video. It may have been making multiple trips to carry bits of the bird to its own nest, says Frankhuizen. When the wasp was done, the baby bird was bloody. It died soon after.

We tend to think that birds prey on wasps, but the opposite can happen, says Thiago Moretti in Campinas, Brazil. He was not involved with the work. But as a forensic entomologist, he applies knowledge about insects to investigate crimes. Wasps are known to visit birds’ nests to get protein-rich snacks, he says. They don’t show up to eat the birds. Wasps munch the mites and parasites that live on birds. Wasps also scavenge carrion. But they rarely attack living vertebrates, Moretti says. With a baby bird, “it is a matter of opportunity.”

A. pallipes lives in big colonies. You wouldn’t expect one to take down a nestling on its own, Frankhuizen says. But other young birds in the same area had similar injuries. That suggests that such attacks may be more common than expected. Frankhuizen and his colleagues report the killing in the October issue of Ethology.

Researchers have observed that many bird species prefer to nest near wasp colonies. Wasps aggressively defend their own nests. That may indirectly defend birds nesting nearby, says Bruno Barbosa. He’s an ecologist, someone who studies how organisms relate to each other. He works at Universidade Federal de Juiz de Fora in Brazil. He was not part of the new study. Birds attacked by a different predator may agitate the insects, he says. This may cause the wasps “to attack everything around them in order to defend their colony.” Making a buzz lets birds benefit from that security system.

Unfortunately, this time, the attack came from inside the nest.