Birds of prey constrained in the beak evolution race

Date:

Share post:

How birds’ beaks evolved characteristic shapes to eat different food is a classic example of evolution by natural selection.

Birds of prey constrained in the beak evolution race
The skulls of a collared falconet (Microhierax caerulescens) and an Andean condor (Vultur gryphus), 
the smallest and largest birds the team studied [Credit: Dr Jen Bright]

However, new research from the Universities of Bristol, Sheffield, Madrid and York, published in the journal Proceedings of the National Academy of Sciences, found this does not apply to all species, and that raptors in particular have not enjoyed this evolutionary flexibility.

Lead author of the study, Dr Jen Bright, said: “Our results show that in birds of prey such as eagles and falcons, the shapes of the skulls change in a predictable way as species increase or decrease in size. The shape of the beak is linked to the shape of the skull, and these birds can’t change one without changing the other.

“We think that being able to break this constraint – letting the beak evolve independently from the braincase, may have been a key factor in enabling the rapid and explosive evolution of the thousands of species of songbirds such as Darwin’s finches and Hawaiian honeycreepers”.

The researchers used a method that allowed them to statistically quantify variation in the shape of predatory bird skulls and see how this shape variation compared with size, what the birds ate and how they are related to each other.

“Our research does not cast doubt on Darwin’s ideas, far from it,” said project lead Professor Emily Rayfield, of the University of Bristol. “Instead it demonstrates how evolution has constrained raptor skulls to a particular range of shapes.”

“Basically, if you’re a bird of prey and you’re small, you look like a tiny falcon, and if you’re a bird of prey and you’re large, your skull looks like a vulture,” said co-author Jesus Marugan-Lobon, of the Autonomous University of Madrid.

The team are now keen to extend and test their ideas in other groups of birds. Project lead Dr Sam Cobb, of the University of York said: “Our results are important because they may help us identify one of the driving factors behind the outstanding diversity of bird species we see in the modern world.”

Source: University of Bristol [April 26, 2016]

ADVERTISEMENT

spot_img

Related articles

Explosive stars with good table manners

An exploding star known as a Type Ia supernova plays a key role in our understanding of the...

Slimbridge Viking axe discounted by archaeologists

An axe head found in a garden in Gloucestershire, which was claimed to be of Viking origin, is...

Egyptian fossil surprise: Fishes thrived in tropics in ancient warm period, despite high ocean temperatures

The Paleocene-Eocene Thermal Maximum, or PETM, was a short interval of highly elevated global temperatures 56 million years...

Roman-era shipwrecks found in deep waters off Greece

Two Roman-era shipwrecks have been found in deep water off a western Greek island, challenging the conventional theory...

Proboscideans of the Hammerschmiede, contemporaries of the first upright ape

Today, there exist only three elephant species, in Africa and Asia. Yet the diversity of proboscidean species and...

Germany now EU’s worst polluter as CO2 emissions rise

Germany is the European Union's worst polluter, with its production of CO2 gasses from fossil fuel rising by...

A step towards temple conservation in India

Over the years, many ornately carved temples in Odisha have been damaged by vagaries of nature, but the...

Stranded orcas hold critical clues for scientists

The development of a standardized killer-whale necropsy system has boosted the collection of complete data from killer-whale strandings...