These touch-sensitive beaks might help seabirds find food at night or underwater, as they might enable the birds to detect tiny vibrations from potential prey. Some birds that are already known to have touch-sensitive beaks use them to detect tiny underground vibrations from worms, for example.

However, these sensitive areas could also be a 'leftover' trait from a common ancestor that doesn't have a specific function in modern birds, like the beaks of ostriches and emus. Further studies in live birds will be needed to establish the exact purpose of these touch-sensitive areas, which may also help determine how the ability evolved.

"In humans and other primates, our sensitive hands and fingers allowed us to master a huge range of environments," said du Toit. "Beaks are analogous to hands in a way, but this is the first time we've seen touch-sensitive beaks in seabirds. It's remarkable that no one has ever really studied this in detail, considering that we all learn about evolution from the beaks of Darwin's finches in school."

The researchers say their findings could potentially play a role in conserving some of these birds. Of the 22 known species of albatross, 15 are threatened with extinction and two are listed as critically endangered. One of the big threats to albatrosses is commercial longline fishing, which kills an estimated 100,000 of the birds per year, when they get tangled in the lines and drown. According to du Toit, if scientists can better understand how these birds get their food, it could be used to help protect them.

"Much further work is needed, but if albatrosses and other seabirds are able to detect vibrations from potential prey via their beaks, it could be possible to attach some sort of device to longlines that could repel them, so they are less likely to get caught," said du Toit. "Of course, the bigger threats to birds like albatrosses are climate change, rising ocean temperatures, plastic pollution and falling fish stocks, but if there's a way to reduce the risks to seabirds in even a small way, then that's incredibly valuable. These are such special birds and I've been interested in them for as long as I can remember."

The research was supported in part by the Royal Society, the Newton International Fellowship, and UK Research and Innovation (UKRI).

Reference:
Carla J. du Toit et al. 'Tactile bill-tip organs in seabirds suggests conservation of a deep avian symplesiomorphy.' Biology Letters (2024). DOI: 10.1098/rsbl.2024.0259