Largest family tree of birds assembled using genetic data shows enlarging size of bird brains | Science News

Scientists from the Milner Centre have published the largest evolutionary tree of birds. The most detailed and comprehensive family tree of birds was assembled from genetic sequence data from 363 families of birds. The research indicates that the sizes of bird brains have been increasing over time.

Brains of birds have grown larger over time. (Image Credit: Oliver Kruger).

New Delhi: The phrase ‘bird-brained’ is used to describe someone who acts absent-mindedly or lacks intelligence. Recent research has indicated that birds are not as unintelligent as they were once believed, and have demonstrated cognitive capabilities comparable to great apes or young human children. Now, a team of researchers have used genetic data to assemble the largest and most detailed family tree of birds, revealing changes to their brain sizes over time.

The data was collected as part of the Brid 10,000 genomes project (B10K), an ambitious attempt to produce draft genome sequences for all extant bird species. The family tree was compiled using data from 363 bird species, spanning 218 families, representing 92 per cent of all bird families. The data was analysed in the context of physical characteristics such as body and brain sizes, along with associated behavioral or ecological traits.

The research allowed for a clarification of the evolutionary lineage of birds, from the time of the dinosaurs to the present day. The researchers showed that the extinction of dinosaurs caused a rapid increase in bird lineages, who diversified to fill in the ecological niches left vacant by the mass extinction event. While changes in the body size slowed down over time, bird brains increased in size and continue to do so today.

Bird genes may contain record of historical environmental changes

A paper describing the findings has been published in Nature. Co-author of the study, Tamás Székely says, “The average body size of medium-sized birds has declined over their evolutionary history, but their brains relative to their body mass has increased indicating enhanced cognition, possibly meaning birds are evolving to become more intelligent. Large brains may also be linked to complex social behaviours, stunning variation in bird song and sophisticated use of tools. In future we want to look at how body size and brain size have evolved in relation to changes in their behaviour, life histories and ecology – these may all relate to changes in their environment during the history of the Earth.”