Birds, brain size and cognitive abilities

According to a new study, the abundance of songbirds with relatively large brains in Eastern Germany and the Czech Republic has increased since 1989-1990. Researchers had compared population trends of bird species in different European regions. The increase in large-brained songbirds is attributed to the better cognitive abilities of the species enabling them better adaption to the socio-economic changes affecting habitats after the end of communism. The scientists discovered that regional differences in population trends among songbird species are linked to their brain size. Large brain size was correlated to strong increases of respective songbird species in the Czech Republic since 1989-1990, weaker increases in Eastern Germany and had no effect in North-Western Germany. This difference between the former West and East suggests that this trend was driven by socio-economic changes that took place in the former communist regions. Relative brain size reflects species' cognitive abilities. The increase of such songbirds suggests that species with good cognitive abilities might have been better able to adapt to rapid socioeconomic change and make use of the novel opportunities that arose after the end of communism. In particular, birds with better cognitive abilities made use of the opportunity to colonize the cities in East Germany and the Czech Republic. After 1989-1990 the inner cities saw an increase in green areas and growing volume of parks, whereas at the same time a newly emerging middle class moved away resulting in a housing boom on the outskirts. Large-brained songbird species such as the Common Magpies, Eurasian Jays and Blue and Grey Tits, show a high behavioral flexibility and hence are better able to live near humans. They could rapidly spread into the new habitats such as new urban greens and suburbs and increase in population size. In contrast, smaller-brained songbird species with less cognitive abilities, such as the Whitethroat, were less able to adapt. The housing boom thus decreased habitat availability for behaviorally less flexible species.