Flight Record: Songbirds Trek 9,000 Miles to Africa

Tiny songbirds weighing no more than two tablespoons of salt apparently globe-trot regularly from the Arctic to Africa, crossing either Asia or the Atlantic to do it, scientists find.

Researchers had known the northern wheatear (Oenanthe oenanthe) had one of the largest ranges of any songbird in the world, with breeding grounds extending from Alaska and extreme northwestern Canada across northeastern Canada and into Europe and Asia. The insect-eating birds apparently leave the Arctic region of the Western Hemisphere for the winter, but it was a mystery as to precisely where they migrated.

Now, using light-sensing tags strapped onto these songbirds, investigators find these birds overwinter in sub-Saharan Africa. Their one- to three-month voyages can reach distances of up to 9,000 miles (14,500 kilometers), covering up to 180 miles (290 km) per day.

"This is the only known terrestrial bird that physically links the two radically different ecosystems of the Old World and the Arctic regions of the New World," said researcher Ryan Norris at the University of Guelph in Canada.

Read on:  http://www.livescience.com/18475-songbird-migration-africa.html

Scared of a Younger Rival? Not for Some Male Songbirds

ScienceDaily (Feb. 7, 2012) — When mature male white-crowned sparrows duel to win a mate or a nesting territory, a young bird just doesn't get much respect.

Researchers found that older male white-crowned sparrows don't put much of a fight when they hear a young male singing in their territory -- probably because the older bird doesn't consider the young rival much of a threat.

But a male sparrow will act much more aggressively if it hears a bird of the same age singing in a territory it claims as its own.

"These male sparrows assess an opponent's fighting ability based on age. And for a mature sparrow, a young male is just not going to scare them," said Angelika Poesel, lead author of the study and curator of Ohio State University's Borror Laboratory of Bioacoustics and the tetrapod division.

Read on:  http://www.sciencedaily.com/releases/2012/02/120207202302.htm

City songbirds victims of noise

PUEBLA, Mexico, Nov. 21 (UPI) -- Noise pollution reduces the presence of songbirds in cities and must be considered when analyzing urban biodiversity, Mexican and Spanish researchers say.
A study by the University of the Americas in Mexico and the Basque Institute for Agricultural Research and Development, carried out in the metropolitan area of Puebla-Cholula in Mexico, revealed green zones most affected by noise have fewer bird species, basqueresearch.com reported Monday.

Among the birds better adapted to urban conditions that are being affected by noise pollution are various species of finches, sparrows and thrushes, the researchers said.

The green spaces studied for the frequency of occurrence of 38 songbirds species included urban parks, main squares, university campuses, natural reserves close to the city and even cemeteries.
Squares and urban parks were the noisiest sites among those studied and, in turn, the ones with a small number of species, researchers said.

The next challenge is to discover what levels of noise can be tolerated by each of the species of birds inhabiting urban environments, they said.

Read more: http://www.upi.com/Science_News/2011/11/21/Study-City-songbirds-victims-of-noise/UPI-50401321913546/#ixzz1eWxCt5q1

It’s All in the Head: Songbirds With Bigger Brains Have Benefited from the End of Communism

ScienceDaily (Sep. 16, 2011) — According to a new study published in Biological Conservation the abundance of songbirds with relatively large brains in Eastern Germany and the Czech Republic has increased since 1989 / 1990. Researchers from German Biodiversity and Climate Research Centre (BiK-F) and Czech Charles University in collaboration with "Dachverband Deutscher Avifaunisten" (Federation of German Avifaunists) 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.

Long-term study of 57 species of songbirds
As part of the study German and Czech scientists investigated the population trends of 57 species of from 1991 to 2007. Data on the abundances of songbird species in Germany was provided by the German "Dachverband Deutscher Avifaunisten" whose volunteers have been operating large-scaling bird monitoring schemes for years. The researchers then tested if individual species' traits and the change in their habitat had a significant effect on population trends. Traits that were matched to population trends included habitat, dietary and climatic niche, migration strategy and brain size in relation to body size. Furthermore researchers wanted to know whether the effects were only regional or universal. In order to find out three different adjacent regions, North-Western, Eastern Germany and the Czech Republic, were compared.

End of communism favored birds with bigger brains
The scientists thus 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." Dr. Katrin Boehning-Gaese, researcher at the Biodiversity and Climate Research Centre (BiK-F) and professor at Goethe-University, Frankfurt am Main, explains.

Better cognitive abilities allow spreading into new habitats
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.

Across the regions birds that are not too picky did better
The study also identifies two other external factors, agricultural intensification and climate change, that had a similar impact in all three examined regions. Bird species with a wider dietary and climatic niche and short-distance migration strategies were on the uptake. In contrast, bird species with a narrower dietary and climatic niche as well as long-distance migration strategies have declined. "The study demonstrates that whereas some factors determine bird population trends in multiple regions, others, in this case the timing of urbanization, act region-specifically." Boehning-Gaese comments. The authors therefore suggest that future studies should consider more regions. This would enable comparison of relationships between socioeconomic change and its impact on bird populations across nations.

http://www.sciencedaily.com/releases/2011/09/110915102206.htm