|European robin (Erithacus rubecula) with scan.|
Researchers at the University of Sheffield asked the public to help measure beak shapes from more than 2000 bird species which have been 3D scanned from specimens at the Natural History Museum and the Manchester Museum.
Using the crowdsourced data, the team were able show that the diversity of bird beaks expanded early in their evolutionary history. The most unusual beak shapes often involved periods of exceptionally fast evolutionary change.
However, once extremes are reached, the changes to bird beaks over time became much smaller as birds filled ever-narrower evolutionary niches.
There are some examples -- such as birds who have evolved in comparative isolation on remote islands such as the Galapagos and the Hawaiian archipelago -- who have continued to evolve rapidly.
Gavin Thomas, the project lead from the Department of Animal and Plant Sciences at the University of Sheffield, said: "The shape of a bird's beak is an important indicator of the food it eats and the way it forages -- its ecological niche.
"This project has given us key insight into how evolutionary processes play out over millions of years -- with major bursts of evolution as new groups emerge, and more fine scale changes thereafter.
"With the efforts of our volunteers from across the world, the study has given us a unique new data set for the study of bird ecology and evolution."
Dr Chris Cooney, from the Department of Animal and Plant Sciences, said: "The great diversity of bird beak shapes has long fascinated biologists and naturalists alike, including Darwin himself. It is wonderful to be able to use the information stored in natural history collections to shed light on how variation in this important ecological trait evolved."
Taking measurements from animals in the wild would have been impossible but 3D models taken from specimens in natural history museums provided new scope for this detailed study.
Members of the public logged onto the website, www.markmybird.org (created by the Digital Humanities Institute, Sheffield) which allowed anyone to access 3D models of the beaks and help create this new resource of bill shapes.
Dr Jen Bright, from the University of South Florida, said: "It's striking how much the speed of evolution changes between different birds. It's a really dynamic process, and it means there are still lots of questions left to answer about how birds managed to come up with the range of beak shapes that they have."
Read more at Science Daily