According to an experimental study, a “smart little head” clearly pays off for pheasants: Individuals who perform particularly well in spatial memory tests roam larger home ranges and are less often preyed on by foxes. It is possible that the birds know particularly well where the predators prefer to lurk, or they know good escape routes there. The results show how cognitive abilities and habitat use in animals can be related, say the scientists.
Being familiar with your environment offers many advantages: We humans are also familiar with this principle and it obviously also plays an important role in the animal kingdom. Because many species don't just move randomly through the landscape—they have ancestral home ranges. They therefore have the appropriate spatial memory and the cognitive abilities to use it. It is obvious that they benefit from special local knowledge in their traditional territories: They know connecting routes, water and food sources or know where conspecifics can often be found. It can also be assumed that they know and avoid sources of danger in their home area.
Tested pheasants on the trail
But all of this is largely based on assumptions – so far there is little experimental evidence of the connection between cognitive abilities and aspects of habitat use. An international team of scientists has now devoted itself to this research topic – using the example of the pheasant (Phasianus colchicus). These mainly ground-dwelling birds are known to move within fairly well-defined home ranges, comprising a core zone and a somewhat less frequented periphery.
For their study, the researchers raised 126 young pheasants and then subjected them to "intelligence tests" at a young age related to spatial memory and orientation skills. Among other things, it was recorded how well the animals could memorize the way through a labyrinth to a food source. It turned out that some pheasants found their way to their destination much more “cleverly” than others. Subsequently, all test animals were released in a semi-natural environment with mixed forests, grasslands and farmland. They carried small transmitters that documented exactly which home ranges the pheasants had established there. The researchers were also able to use the tracking system to record when and where an animal died. Subsequent investigations also clarified the respective cause.
As the team reports, the data evaluations initially revealed a fundamental connection: Those birds that had performed better in the cognitive tests established comparatively large home ranges - they developed a wider range of activity than individuals with more modest performance. As far as deaths are concerned, about 40 percent of the pheasants were killed by foxes during the six-month study period. Statistically, the specimens that were successful in the tests were somewhat less affected, the evaluations showed.
With "knowledge" against thieves
Another finding suggested that this could be related to the comparatively good local knowledge of the pheasants. Basically, it was shown that these birds are more often caught in the peripheral areas of their respective home areas, where they are less familiar than in the core areas. The results showed that a lack of knowledge is the decisive factor and not the potential danger at certain points. Because other test animals that knew the same spots well were not more likely to die there. "For pheasants, experience in an area appears to be much more important in predicting whether they will be killed by predators than the dangerousness of the area itself," says lead author Robert Heathcote.
According to him, pheasants could benefit from two lessons learned: “Predators such as foxes are often habitual in their hunting behavior, so pheasants in the area may know certain places where predators prefer to stalk them. Another explanation is that over time pheasants gain more knowledge of the quickest and safest local escape routes when attacked,” says Heathcote.
Finally, co-author Joah Madden from the University of Exeter summarizes the significance of the results: “They suggest that basic spatial abilities are related to real-world space use in the wild and are critical to the survival of individuals when threatened by predators affect. We were able to show that knowledge of an area helps pheasants stay alive, and this means that these cognitive abilities can be shaped through natural selection. We now understand a bit more about how cognitive abilities can develop in animals.
Source: University of Exeter, professional article: Nature Ecology and Evolution, doi: 10.1038/s41559-022-01950-5
https://www.nature.com/articles/s41559-022-01950-5