Brain Matters

Historians have spent years debating the consequences of the fall of the Iron Curtain that once divided capitalist Western Europe from the communist nations to the east. But they’ve probably never thought about how it affected bird populations – or how the size of a bird’s brain might influence its ability to adapt to historic socioeconomic shifts. Now, a new study suggests that birds with bigger brains have done better in handling the transition from communism.

Three adjacent regions in central Europe — Northwestern Germany, Eastern Germany and the Czech Republic – “experienced very different socioeconomic histories” after the fall of communism, Jiri Reif of Charles University in Prague and colleagues from Johannes Gutenberg University in Mainz, Germany note in Biological Conservation. In Northwestern Germany, which was already capitalist, agriculture became more intensive and urban development expanded little. In contrast, farming underwent “profound changes” in the former East Germany, and “nearly collapsed” in the Czech Republic. At the same time, economic growth led to the regreening of city centers and the creation of suburbs in the former communist nations.

To see how these trends affected bird populations, the researchers compiled data on socioeconomic trends in the three regions, and population data on 57 species of songbirds. Then, they used statistical techniques to explore how population trends were influenced by a range of factors, including habitat changes, dietary and climatic niche, migration strategies, and cognitive ability, as measured by relative brain size.

Most of the factors appeared to affect bird populations similarly in the three regions. But brain size apparently made a big difference in the former communist nations: Birds with bigger brains tended to show a slight uptick in populations sizes in East Germany, and even bigger gains in the Czech Republic. The “increases of species with large brains suggest that species with good cognitive abilities might have been better able to adapt to rapid socioeconomic change and make use of novel opportunities after the end of communism,” the authors write.

A key factor, they speculate, was urbanization, which “offered new habitats for species with large brains and high behavioral flexibility that are able to live near humans in urban areas.” The “emergence of new habitats due to the housing boom in the Czech Republic allowed the urbanization of species that were already partly urbanized (e.g. Common Magpie or Eurasian Jay),” and helped them “spread into new sites,” they speculate. “Alternatively, changes in the quality of urban habitat in city centers (namely increase of green areas and growing volume of woods) could have facilitated the colonization of cities” by bird species typically found in forests.

It is possible that some factor other than brain size might be responsible for the trends, the authors caution. But they say that more studies examining the links between large-scale changes in human societies, and the cognitive abilities of birds and other animals, could produce some thought-provoking insights. David Malakoff | August 7, 2011

Source: Reif, J., et al. Population trends of birds across the iron curtain: Brain matters. Biol. Conserv. (2011), doi:10.1016/

Image © Isselee |