Neurobiologists investigate neuronal basis of crows' intelligence

November 29, 2013 by Antje Karbe
Credit: Felix Moll, Institute for Neurobiology, University of Tübingen

Scientists have long suspected that corvids – the family of birds including ravens, crows and magpies – are highly intelligent. Now, Tübingen neurobiologists Lena Veit und Professor Andreas Nieder have demonstrated how the brains of crows produce intelligent behavior when the birds have to make strategic decisions. Their results are published in the latest edition of Nature Communications.

Crows are no bird-brains. Behavioral biologists have even called them "feathered primates" because the make and use tools, are able to remember large numbers of feeding sites, and plan their social behavior according to what other members of their group do. This high level of intelligence might seem surprising because birds' brains are constructed in a fundamentally different way from those of mammals, including primates – which are usually used to investigate these behaviors.

The Tübingen researchers are the first to investigate the brain physiology of crows' intelligent behavior. They trained crows to carry out memory tests on a computer. The crows were shown an image and had to remember it. Shortly afterwards, they had to select one of two test images on a touchscreen with their beaks based on a switching behavioral rules. One of the test images was identical to the first image, the other different. Sometimes the rule of the game was to select the same image, and sometimes it was to select the different one. The crows were able to carry out both tasks and to switch between them as appropriate. That demonstrates a high level of concentration and mental flexibility which few animal species can manage – and which is an effort even for humans.

The crows were quickly able to carry out these tasks even when given new sets of images. The researchers observed neuronal activity in the nidopallium caudolaterale, a brain region associated with the highest levels of cognition in birds. One group of nerve cells responded exclusively when the had to choose the same image – while another group of cells always responded when they were operating on the "different image" rule. By observing this cell activity, the researchers were often able to predict which rule the crow was following even before it made its choice.

The study published in Nature Communications provides valuable insights into the parallel evolution of intelligent behavior. "Many functions are realized differently in birds because a long evolutionary history separates us from these direct descendants of the dinosaurs," says Lena Veit. "This means that bird brains can show us an alternative solution out of how intelligent behavior is produced with a different anatomy." Crows and primates have different brains, but the cells regulating decision-making are very similar. They represent a general principle which has re-emerged throughout the history of evolution. "Just as we can draw valid conclusions on aerodynamics from a comparison of the very differently constructed wings of birds and bats, here we are able to draw conclusions about how the brain works by investigating the functional similarities and differences of the relevant brain areas in avian and mammalian brains," says Professor Andreas Nieder.

Explore further: Crows found able to distinguish between human voices

More information: Lena Veit & Andreas Nieder: Abstract rule neurons in the endbrain support intelligent behavior in corvid songbirds. Nature Communications; DOI: 10.1038/ncomms3878

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3.4 / 5 (5) Nov 29, 2013
They are impressive creatures. I've seen them doing cooperative and ever sympatric behavior. When collecting the road kill in the morning, one will land in the highway while his partner keeps traffic watch nearby. There are a lot of them in my area, and I like to go hiking. So, I've seen two or three occasions where a crow is down and apparently unable to fly. Each time, there have been several other crows hovering or landed in the area – apparently consoling their friend.
2.3 / 5 (3) Nov 29, 2013
Crows will remember you if you rescue them as fledglings from local carnivores, like house cats and foxes, and transfer them to a safe place. The parents are always nearby watching you do this and they will continue to look after the young birds. One time I was fishing from a pier about 25 miles from home when a crow came out of the sky and lit on my left shoulder. I am convinced that it was the same crow that I found fluttering helplessly on the ground a couple of years before and had relocated to a safe place after looking after it for a few days. The adults were never far away.
not rated yet Nov 29, 2013
You may be right, and it's a pretty amazing thought! Long story short, a crow was trapped under a plastic cover in my backyard. Luckily I noticed him/her and and moved him over to the pond in my backyard (the guy was exhausted) so he could recover and get a drink. I brought him some food (some fruit, if I remember correctly) as well. It didn't take him that long to get at least some of his strength back, maybe an hour or so, but when he could he flew away. Ever since that day, many more crows use our pond as a bath (it has a shallow upper part the birds can stand in). It's speculation, but every once and a while a crow will linger around the pond, have an extra long bath, and look at me a lot longer than your typical crow. I'd like to think it is the same crow.
not rated yet Nov 30, 2013
We had a group of crows regularly roosting in a nearby tall tree.

One afternoon the tree was cut down, and the returning crows were circling around the site wondering what happened to their tree.

I would like to know how crows tell each other apart since they all look the same ! I have also heard that crows can be trained to talk - like parrots can.
not rated yet Dec 02, 2013
I know for a fact that magpies can mimic human words in much the same way that parrots can, because I used to know one when I was a kid, and I think they are of the same corvid family as crows.

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