Anyone who likes to climb would sometimes be happy to have an extra leg or an extra hand.

Unfortunately, nature does not intend this.

However, parrots know how to help themselves in other ways and use their beaks as well as their feet when climbing.

So far, however, it has not been clear whether the bird just uses it to attach itself or whether it also uses its beak to move forward.

Scientists led by Melody Young and Edwin Dickinson from the New York Institute of Technology College of Osteopathic Medicine in Old Westbury recently discovered that parrots can actually use their heads and beaks as a third leg.

They used six rose-heads (

A

gapornis roseicollis) as research objects.

This small parrot, which is also popular as a pet, inhabits various biotopes in its south-west African homeland, from dry forests and savannas to semi-deserts.

His climbing skills are not only useful in the branches of trees, where there are seeds and fruits to harvest.

Such skills are also required at the nest that the rose-necked lovebird builds in rock crevices, or as lodgers in the huge communal nests of weaver birds.

To watch the parrots climb, Young and colleagues had their feathered subjects walk across a handy board that could be placed at different angles.

At an angle of 45 degrees, the uphill-marching birds began to brace themselves with their tails and occasionally use their beaks as well.

When they had to climb vertically, they always used their tails and beaks to help them wherever they went.

The tail only acts as a support

On their way up, the parrots were not only filmed, they also passed measuring devices that registered exactly how much force the feet, tail and beak exerted on the ground - and in which direction.

As relevant analyzes showed, the tail only acted as a support, as expected.

On the other hand, the bird pushed off vigorously with its beak as if it were its legs in order to move forward.

The beak also stabilized the parrot's posture with just as much force ("Proceedings of the Royal Society B").

The head and beak did almost as much work as a leg.

As a parrot climbs a vertical wall, its head and beak join in with the regular rhythm of its hind legs.

And in such a way that there is never just one point of contact with the wall, but always at least two points at the same time.

While the head and beak work against gravity, they not only propel the parrot forward on its way up.

They also prevent the bird from tipping backwards.

In relation to their body weight, the parrots grip with their “third leg” with as much force as climbing humans or monkeys do with their arms.

A strong neck musculature

Experience has shown that parrot beaks can bite hard, for example to crack hard nuts.

With the muscles provided for this, the birds can probably also effortlessly prevent themselves from falling off the climbing wall.

In order for them to move forward there, however, the neck flexors are required.

It can therefore be assumed that these muscles are significantly stronger relative to body weight than, for example, the neck muscles of humans.

Woodpeckers, wallcreepers and many other birds can also climb vertical tree trunks or rocks with seemingly no effort.

But apart from parrots, no other bird uses its head and beak as an extra leg.

How parrots manage to integrate these body parts into the movement rhythm of their legs remains an open question.

Perhaps, as Young and colleagues suspect, it was not necessary to develop completely new connections between nerves and muscles.

It is typical for birds that the head moves in step rhythm.

This is particularly noticeable with pigeons: when they walk around, they nod their heads.

As a result, your eyes temporarily assume a constant position in space.

This is probably advantageous because it is difficult to capture movements in the environment precisely while you are on the move and the field of vision is moving accordingly.

It is possible that parrots have modified the usual head nod in such a way that the head and beak harmonize optimally with their legs.