Several animal species can survive within cities by changing their behavior; such changes could be the result of evolutionary adaptation, epigenetic effects, or come from preadapted traits through phenotypic plasticity or non-random dispersal. Exploring whether behavioral preadapted traits are present in non-urbanized populations could improve our understanding of the processes that allow animals to cope with urbanization. We compared the boldness, neophobia, and solving-test skills of adult individuals of the Chiguanco Thrush (Turdus chiguanco) between urban and extra-urban habitats in La Paz (Bolivia), a high-altitude Neotropical city. The urban Chiguanco Thrushes were bolder, less neophobic, and performed better in problem-solving tests. Extra-urban individuals varied significantly more among them in boldness and neophobia, and although a smaller proportion of individuals were able to solve the simplest problem-solving test, they did so in the same way as the urban ones. This evidence suggests that the behavioral responses of the Chiguanco Thrush to urbanization in La Paz come from preadapted traits.

An adult Chiguanco Thrush (Turdus chiguanco) captured with a mist net in an urban public green space in the city of La Paz,Bolivia (spring, 2016), and temporarily kept in captivity for four days for the evaluation of problem-solving skills. We built two types of problem solving boxes made of translucent white plastic. The one on the videotape is called a "tube test" (5 cm high × 5 cm wide × 20 cm long), it had an opening on one side, inside the tunnel was a wooden stick (25 cm) with a hook attached to the end that was outside the tunnel, we put the food on the other end of the stick, the one that was inside the tunnel. The bird needed to realize that the only way to get to the food was to pull the stick with its beak using the hook. We videotaped the tests with a GoPro HERO camera from the first approach until the bird solved the test.