City-life changes blackbird personalities, study shows

Jun 18, 2013
This image shows behavioral experiments on urban and forest-dwelling blackbirds. Urban blackbirds wait longer than their forest-born counterparts before approaching a new object (in this case, a plastic cup). Credit: MPI for Ornithology/Ana Catarina Miranda

The origins of a young animal might have a significant impact on its behavior later on in life. Researchers at the Max Planck Institute for Ornithology in Radolfzell, Germany, have been able to demonstrate in hand-reared blackbirds that urban-born individuals are less curious and more cautious about new objects than their country counterparts. This study sheds light on an interesting debate on whether personality differences between rural and urban birds are behavioral adjustments to urban environments, or if there is an underlying evolutionary basis to the existence of different personalities in urban habitats.

It's something pet owners have always known: animals have personalities too. More than 100 species have so far been identified by scientists where individuals consistently follow distinct and behave in similar ways in a variety of situations. Scientists believe that such differences may also be important in adapting to new habitats.

Urbanization has considerably changed the living conditions of many . Animals living in urban areas need to cope with new anthropogenically-altered living conditions. A textbook example is the European blackbird (Turdus merula). Historically a forest-dweller, the blackbird is now one of the most common found in our cities. In these new habitats, the blackbird has changed its behavior in many ways: urban migrate less in the winter, breed earlier, and live in higher densities than their forest conspecifics.

Cities might be also responsible for fundamental changes in the behavior of wild animals across the globe. A team from the Institute for Ornithology in Radolfzell analyzed existing studies on differences between urban and rural populations of various species. In 27 out of 29 studies, animals in the city responded differently to new stimuli than animals in the countryside. "This seems to be a ," comments Ana Catarina Miranda, the lead author in the study.

This image shows the hand-rearing of urban and rural blackbird nestlings. Credit: MPI for Ornithology/Jesko Partecke

Moreover, the Radolfzell scientists tested whether or not these behavioral differences also reflect different personality types and if so, whether this is a result of evolutionary changes or individual flexibility. To this end, the scientists collected nestlings from an urban and a rural environment, hand-reared them and kept them individually under identical conditions. When these blackbirds matured into adults, the researchers repeatedly presented individuals with unfamiliar objects over a period of several months.

Compared with birds from the forest, the birds from the city waited much longer before they approached a new object. Not only did urban blackbirds react more cautiously towards new objects, they also tended to avoid unfamiliar objects. Since all the birds were collected as nestlings, hand-reared, and kept under identical conditions during the entire experiment, the differences in behavioral responses between urban and rural blackbirds seem to be intrinsic and not a result of experiencing the original urban or rural environments. A recently published study supports these findings: Genes which are believed to be involved in shaping personality traits exhibit a different structure in urban blackbirds than in their rural counterparts.

This work is an important step to understand how animals cope with our urbanizing world. Different reasons might be behind differences in personality types between urban and rural animals, and this is a question to be further explored. "Animals in fast-paced face numerous and potentially dangerous new situations, and this might select for specific reactions towards novelty," suggests Miranda. "Evolution appears to have favored certain personality types."

Explore further: Personality test finds some mouse lemurs shy, others bold

More information: Miranda, AC, Schielzeth H, Sonntag T, Partecke J (2013) Urbanization and its effects on personality traits: a result of microevolution or phenotypic plasticity? Global Change Biology, June 19, 2013, doi: 10.1111/gcb.12258

Related article:
Mueller JC, Partecke J, Hatchwell BJ, Gaston KJ, Evans KL (2013) Candidate gene polymorphisms for behavioural adaptations during urbanization in blackbirds. Molecular Ecology, online in advance of print. doi: 10.1111/mec.12288

Related Stories

Clamorous city blackbirds

Jan 11, 2013

(—Animals have developed a variety of strategies for dealing with increasing noise pollution in their habitats. It is known, for example, that many urban birds sing at a high pitch to differentiate ...

Urbanization favors sedentary males

May 01, 2007

Urbanization changes landscapes and local environments, which can alter the life histories and traits of the creatures living in and around these areas. Studying European blackbirds (Turdus merula), Jesko Partecke and Eberhard ...

Personality test finds some mouse lemurs shy, others bold

Jun 18, 2013

Anyone who has ever owned a pet will tell you that it has a unique personality. Yet only in the last 10 years has the study of animal personality started to gain ground with behavioral ecologists, said Jennifer ...

City birds adapt to their new predators

Nov 07, 2012

Faced with the same threat, city and country birds do not react in the same way despite being from the same species. According to a new study, urban birds have changed their anti-predator behaviour in new ...

Recommended for you

Male monkey filmed caring for dying mate (w/ Video)

Apr 18, 2014

( —The incident was captured by Dr Bruna Bezerra and colleagues in the Atlantic Forest in the Northeast of Brazil.  Dr Bezerra is a Research Associate at the University of Bristol and a Professor ...

Orchid named after UC Riverside researcher

Apr 17, 2014

One day about eight years ago, Katia Silvera, a postdoctoral scholar at the University of California, Riverside, and her father were on a field trip in a mountainous area in central Panama when they stumbled ...

In sex-reversed cave insects, females have the penises

Apr 17, 2014

Researchers reporting in the Cell Press journal Current Biology on April 17 have discovered little-known cave insects with rather novel sex lives. The Brazilian insects, which represent four distinct but re ...

Fear of the cuckoo mafia

Apr 17, 2014

If a restaurant owner fails to pay the protection money demanded of him, he can expect his premises to be trashed. Warnings like these are seldom required, however, as fear of the consequences is enough to ...

User comments : 0

More news stories

Biologists help solve fungi mysteries

( —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...

Researchers successfully clone adult human stem cells

( —An international team of researchers, led by Robert Lanza, of Advanced Cell Technology, has announced that they have performed the first successful cloning of adult human skin cells into stem ...

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.