Urban blackbirds are more cautious than country birds
City-dwelling blackbirds are more cautious than their rural counterparts, researchers have found.
The team collected 28 young blackbirds from nests in Munich, Germany and 25 from a nearby forest. Then the researchers raised all the birds under the same conditions.
To find out if the urban and rural birds had different personalities, the team conducted two types of tests. In one test, the researchers added a new object to a perch in the bird’s cage and timed how long the bird waited before approaching it. The second test was similar, except that the new object was close to the bird’s food source.
When the unfamiliar object was near the feeder, the city birds waited an average of half an hour longer than the country birds to perch by it on the first day and 16 minutes longer on the second day. Some urban birds — but none of the rural birds — refused to approach the object during the entire trial, the team reports in Global Change Biology.
Urban birds might avoid new objects because they’re more likely to encounter unfamiliar hazards in cities, the researchers suggest. Since all the birds were raised the same way and had never left their nests before they were collected for the experiment, the personality differences are probably genetic, the team says. — Roberta Kwok | 21 May 2013
Source: Miranda, A.C. et al. 2013. Urbanisation and its effects on personality traits: a result of microevolution or phenotypic plasticity? Global Change Biology doi: 10.1111/gcb.12258.
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