Scientists crack mystery behind shape of bird eggs

Fascinating article from phys.org .  Follow the link here to the website and article.

August 23, 2018 , University of Sheffield

Scientists crack mystery behind shape of bird eggs
Credit: University of Sheffield

A centuries-old mystery behind the shape of a bird’s egg has been solved by scientists at the University of Sheffield as part of one of the longest-running scientific studies of its kind.

The study, led by Professor Tim Birkhead from the University’s Department of Animal and Plant Sciences, has discovered the reason why guillemot eggs have such a peculiar shape – a mystery that has been puzzling biologists for hundreds of years.

Guillemots lay and incubate their single egg on bare cliff ledges close to the sea, which led scientists and nature enthusiasts to believe that the egg’s pointed shape had evolved to help it roll in an arc – thus keeping it from the cliff edge should it become dislodged

However, Professor Birkhead, who has been studying the behaviour of guillemots, puffins and razorbills on Skomer Island in Wales for almost 50 years, has discovered that the egg’s shape has evolved in order to keep the egg in place and prevent it from rolling away in the first place.

 

Origin of the species: where did Darwin’s finches come from? – the guardian.com

Galápagos finches have been the subject of a plethora of evolutionary studies, but where did the first ones come from?

Four of the species of finch observed by Darwin on the Galápagos Islands, showing variation of beak.
Four of the species of finch observed by Darwin on the Galápagos Islands, showing variation of beak. Photograph: Ann Ronan Pictures/Print Collector/Getty Images

When the first of the Galápagos Islands arose from the ocean floor around 3m years ago, they were naked, angry, lava-spewing cones devoid of life. Now, millions of years later, they are alive with some of the world’s most iconic animals. Giant tortoises. Sea iguanas. Flightless cormorants. And those finches equipped with Swiss army knife beaks.

The Galápagos finches are probably one of the most well-known examples of evolution and will forever be tightly linked to Charles Darwin’s voyage and his theory of natural selection (although you may be surprised to learn that the Galápagos finches were not as central to Darwin’s theory as we like to think). With their diversity of bill sizes and shapes, each species has adapted to a specific type of food; the ground-finch (Geospiza) has a thick beak adapted to feeding on a variety of crunchy seeds and arthropods, whereas the warbler finch (Certhidea olivacea) developed a slender, pointy bill to catch tasty insects hiding between the foliage. The woodpecker finch(Camarhynchus pallidus) even uses twigs or cactus spines to pry arthropods out of treeholes

Read the full article here.