Migratory birds have smaller brains. And..?

Researchers at Centre for Ecological Research and Forestry Applications…shed new light on the evolution of brain size in birds. Scientists have known for some time that migratory birds have smaller brains than their resident relatives. Now a new study looks into the reasons and concludes that the act of migrating leads to a reduced brain size…

Understanding brain evolution is something that has interested scientists since the times of Charles Darwin, who considered that the large size of a human brain went hand in hand with the exceptional cognitive capacities of our species. One of the classic explanations is the protective brain theory, which suggests that a large brain — in comparison to body size — makes learning easier. This protects individuals from changes in the environment, such as those produced by changes in season. In the case of birds however not all species respond to seasonal changes in the same way. Migratory birds avoid these changes by travelling to less inhospitable places when conditions worsen. This is the strategy followed by swallows or cuckoos. Resident bird species stay in the same area throughout the year and face strong environmental fluctuations. Tits and crows belong to this group…

The study…points to the fact that being a migratory bird is what makes these birds have smaller brains. Researchers came to this conclusions by reconstructing the evolutionary history of passerine birds and determining the sequence of evolutionary changes which most probably led to the current situation. In the case of this group of birds “the first step was changing from a resident to a migratory life and the second step was a reduction in the size of the brains of migratory birds,” Daniel Sol explains. “Therefore,” he adds, “differences in brain sizes are not caused by nature’s need to provide resident species with larger brains, as suggested in the protective brain theory, but to provide migratory species with smaller brains.”

Normally a larger brain offers many advantages. Then why is it that in the case of migratory birds natural selection has favoured smaller brains? The study highlights various explanations, but the general idea focuses on the possibility that a large brain does not necessarily have to be better. According to Daniel Sol, “the brain is an organ that consumes a lot of energy and develops slowly and this can be too costly for migratory species which must travel far and have little time to reproduce.”

Several interesting ideas in the study. Some of which would be useful to a stand-up comedian.

The rest are meaningful to evolutionary biologists.

One thought on “Migratory birds have smaller brains. And..?

  1. Killzall says:

    “Egged on by industry lobbyists, Interior Dept. weakens bird protections” https://www.revealnews.org/article/egged-on-by-industry-lobbyists-interior-dept-weakens-bird-protections/ “…The decision to revoke the authority stunned former top Interior Department officials who have served presidents from both parties. Department officials from all administrations since the 1970s signed a letter opposing the solicitor’s office’s legal opinion, saying it contradicts the way the law has been implemented for decades and ignores birds’ important role in ecosystems. https://defenders.org/publications/mbta-zinke.pdf “Birds are, quite literally, the proverbial ‘canary in the coal mine,’ ” says the letter to Interior Secretary Ryan Zinke. “How birds fare in the world indicates how all wildlife and habitat, and by extension human populations, will fare.”
    Zinke “is obviously acting to protect the interests of drilling companies that have unprotected ponds that are killing birds,” said Nathaniel Reed, who was assistant secretary for fish, wildlife and parks under Republican Presidents Richard Nixon and Gerald Ford. “It’s an enormously significant backward step.”

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