The crows have become a routine part of our landscape. How smart are they really, and why is one species more successful than another?
They say that they are vindictive, that they are bad omens or that they are just loud; Crows got a bad name, and that's without even mentioning Hitchcock's movie. But while you're walking in the neighborhood park, have you noticed the curious look with which a crow watches you? Maybe you've seen him solve complex problems to get to food, or heard about the ability of crows to remember human faces for years? Crows are among the smartest creatures in the animal kingdom. In recent years, scientists are discovering that crows are endowed with impressive cognitive abilities which compete with those of the monkeys in certain areas and even of small children.
A recent Israeli study examined the cognitive abilities of two similar species of crows that reacted differently to changes in their living environment. "We decided to test the cognitive and personal abilities of the crows," says Prof. Ran Natan, from the Laboratory of Movement Ecology, the Hebrew University of Jerusalem. "In the beginning, we assumed that there was no significant difference between the sexes."
Similar but different
These two species of crows live in the Judean desert, and they have experienced many environmental changes in the last hundred years, such as the development of settlements and industry, the drop in the level of the Dead Sea and intensive tourism in the area. The crow is the brown of the nape of the neck Relatively large, it nests on trees and cliffs, and to obtain food it flies in pairs or small groups. It tends to visit areas with human activity such as feeding stations, restaurants, parking lots and dumps, and over the years its population has grown. on the other hand, The short-tailed crow As his name suggests, he is characterized by a short tail. It moves in small groups and feeds on small animals and human garbage. Unlike the brown-backed crow, its population has dwindled and today it is found mainly in the cliffs of the Dead Sea.
The choice of two species of crows that are so similar but with very different reactions to changes in their environment aroused the curiosity of the researchers, who wanted to understand if there is a difference in their cognitive abilities and if this is what helps them deal with environmental pressures. "We brought the crows to the laboratory for a short period of about a month in a season that does not interfere with nesting," explains Natan. The researchers used a sophisticated Australian trap - a kind of large cage with an open roof and a ladder. Into the cage they put a crow of the same species they wanted to capture and food as a lure. The crows, known for their great curiosity, came and examined the cage, and after deciding that the place was safe, they went inside.
At the university, the captured crows stayed in a facility that closely resembles their natural environment to ensure their well-being. "We gave them time to adapt to the place and food they like, and only after we noticed that they were calm and comfortable, we started a series of complex tests," says Natan.
"Only after we noticed that they were calm and comfortable, we started a series of complex tests" Photo: Prof. Ran Natan
How do you measure a crow's cognitive ability?
One of the interesting tests tested the spatial memory of the crows. The researchers placed three covered plates in each corner of the room, only one of which contained bamba - a food especially loved by the crows. They repeated the experiment several times and checked whether the crows remembered in which plate the bamba was waiting for them or whether they would continue to check all the plates again and again until they reached the one with the snack inside. They summed up the number of mistakes made by each crow in each repetition, and noticed that the number of mistakes made by most of the crows decreased from repetition to repetition. However, the short-tailed ravens outperformed the ravens - they made fewer mistakes and were more successful in finding food.
Another test examined the willingness of the crows to take risks. First, the researchers placed plates of food in an empty room, brought the crows into the room and measured how long it took them to approach the plates. Then the same experiment was repeated, but this time a person was sitting in the room. The researchers measured how long it took the crows to access the food in the presence of the human and how long they spent near the plates. The results showed significant differences, with the short tails surpassing the nape browns in the degree of boldness. "There were crows who took a few minutes to decide whether to enter the room and eat from the plates, while others chose not to enter at all, which means there are differences between them in their willingness to take a risk."
Another experiment tested the problem-solving ability of the crows. The researchers placed a transparent cylinder balanced on the ground with Bamba inside. In order to get the food, the crow had to understand that it had to go to the side of the roll instead of pecking at it directly. The researchers measured the amount of time it took the crows to understand and solve the problem. Some of the crows solved the challenge in a few seconds while others did not succeed at all. In this case too, the short-tailed crows achieved better results than the brown-necked crows.
One of the interesting tests tested the spatial memory of the crows. Photo: Prof. Ran Natan
The smart one wins?
The results of the study showed that both species of crows have high performance capabilities. In a small part of the tests, equal results were achieved, but in the spatial memory tests and willingness to take risks, the short-tailed crow excelled. Although the brown-backed crow appears to be more successful in terms of geographical spread, it is the short-tailed crow that exhibits higher cognitive abilities. This raises questions about the factors that influence the success of a particular species of animal in a changing environment, beyond cognitive abilities alone. Natan hypothesized that the cognitive abilities probably serve another need: "If the crow does a certain action it is difficult for us to know if it is because of a lack of fear or because it is less smart or maybe something else altogether; This is a field that is in development."
In the second phase of the study, GPS devices were installed on the crows and they were released back into the wild. In this way, the researchers hope to understand how the crows use their cognitive abilities in real situations, and deepen the understanding of the complex interaction between the crows and their changing environment. This research raises fascinating questions about the relationship between cognitive abilities, adaptation to environmental changes, and evolutionary success. The information may help in understanding the different strategies that species develop to deal with environmental changes, and may even provide clues about ways to preserve species at risk.
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