Scientists employing hidden night-vision cameras have revealed for the first time the secret, sinister childhood of African honeyguides, birds long revered by humans for their considerate habit of guiding people to honey-rich bee colonies, according to the BBC.

The video, filmed by scientists from the University of Cambridge, shows a honeyguide chick engaging in a brutal killing spree within days of hatching.

Honeyguides have long been known to be "brood parasites," meaning they lay their eggs in the nest of another species, tricking the host species into raising their young. It's hardly an honest enterprise, but until now scientists had no idea how sinister the practice was because honeyguides typically choose a host species that nests in underground burrows or a covered nest.

That's where the hidden cameras came in handy. "We buried infrared video cameras within the hosts' underground nests to see what happened," explained Dr. Claire Spottiswoode, who led the research.

Scientists feared the scene might not be pretty, since previous studies had suggested that honeyguide chicks are born with specially adapted needle-sharp beaks. You can view the video here, but be forewarned: it's graphic.

"While the apparent violence with which young honeyguides attacked their newly hatched foster siblings was quite shocking at first sight, it shows the power of evolution to shape amazing adaptations in parasites," said Spottiswoode.

By killing the other chicks in the nest — chicks that are not honeyguides — the honeyguide improves its odds of survival and allows it to receive all of the parental care from the host. Furthermore, adult honeyguides give their chicks an early head start by incubating their eggs a day before laying them, which increases the odds that they will hatch first. They also puncture any eggs already been laid by the host species.

After about a month of receiving exceptional care from their adoptive parents, the chicks lose their menacing beak-hooks, leave the nest, and go on to become model citizens — at least in the eyes of humans in search of honey.

The birds enjoy a sparkling reputation as adults. Of course, that was before we knew just how evil they were as chicks, with their dagger-like beaks and killer instincts.

"Each time brood parasitism has evolved we see specialized adaptations, which are no less astonishing for being sometimes rather gruesome," said Spottiswoode.