Wild Neighbors: Post-Communist Birds

By Joe Eaton
Wednesday September 21, 2011 - 03:07:00 PM
Eurasian Jay in Berlin: a post-Cold War winner.
Richard Bartz (via Wikimedia Commons.)
Eurasian Jay in Berlin: a post-Cold War winner.

Earlier this year I reported on a study out of Finland that contended that, in Europe at least, passerine (songbird) species with relatively larger brains made out better in urban areas than did smaller-brained species. Winners included corvids (crows and magpies), tits (relatives of the North American chickadees), nuthatches, and wrens. Buntings, Old World warblers, and Old Word flycatchers were among the small-brained city avoiders. 

Well, science marches on. Now there’s another report, this time from a group of German and Czech biologists, purporting to show that large-brained passerines benefited more from the fall of Communism than small-brained passerines. 

Jiri Reif and colleagues analyzed population trends for 57 species from 1991 to 2007 in the Czech Republic, the former East Germany, and, as a control, the northern portion of the former West Germany. They looked for effects of habitat, diet, climate preference, migratory strategy, and relative brain size as a proxy for cognitive ability. 

Their conclusion: larger brain size correlated with strong population increases in the Czech Republic and weaker increases in eastern Germany. As in the broader Finnish study, the corvids and tits led the pack. Northwestern Germany, though, showed no clear trend. 

If it weren’t for the national differences, I’d wonder about spurious correlations here. Corvids, with a few sad exceptions like the Hawai’ian crow, are among the most adaptable of birds. I’m not surprised that their Czech populations have grown since the Velvet Revolution. It’s likely their populations in most places have grown since Crash of 2008, or 9/11, or the cancellation of Star Trek, the original series. 

As to why those particular patterns, the others say the years since 1989 saw an increase in parks and other green spaces in urban areas and a middle-class exodus to newly built suburbs. Corvids and tits had the smarts and behavioral flexibility to exploit both city parkland and suburban habitats; less-favored birds did not. This begs the question of what all that suburban housing replaced and displaced, but give them the benefit of the doubt. Brainier birds also coped more successfully with agricultural intensification. Northwestern Germany, they argue, didn’t undergo the same economic/demographic changes as its ex-Communist neighbors, so there were no new worlds for the corvids to conquer. 

I’d like a little more context about the underlying changes. The Soviet Union and its European satellites did not have stellar environmental records. Decision makers in centrally-planned economies were just as prone to externalize environmental (and social) costs as their capitalist counterparts. But the damage they did may have been constrained by inefficiency and inertia; consider the post-Gorbachev pillage of Siberia. 

Another, older article suggests that the old regimes may at least have been good for native birds. A couple of years ago, biologists at the Hebrew University of Jerusalem reported that the isolation of the Eastern bloc during the Cold War led to a decline in introductions of non-native species. Only six non-European bird species became established in Eastern Europe between 1949 and 1991, versus 52 in Western Europe. The latter group had a preponderance of parrots, finches, and other pet-trade standards. 

I hope someone does a follow-up. You have to wonder if there are flocks of wild parrots in Bucharest and Sofia these days.