Tuesday, February 08, 2011

More Evidence that Birds Can Adapt to Urban Noise Conditions

A new study by researchers from Universidad Nacional Autónoma de México and the Museo Nacional de Ciencias Naturales shows that House Finches are capable of making short-term adjustments to their vocalizations in urban environments, which typically are louder than more natural environments.

The study suggests that some bird species are capable of adapting to urban acoustic environments.

ABSTRACT

Experimental evidence for real-time song frequency shift in response to urban noise in a passerine bird

Eira Bermúdez-Cuamatzin, Alejandro A. Ríos-Chelén,Diego Gil and Constantino Macías Garcia

doi: 10.1098/rsbl.2010.0437
Biol. Lett. 23 February 2011 vol. 7 no. 1 36-38

Research has shown that bird songs are modified in different ways to deal with urban noise and promote signal transmission through noisy environments. Urban noise is composed of low frequencies, thus the observation that songs have a higher minimum frequency in noisy places suggests this is a way of avoiding noise masking. Most studies are correlative and there is as yet little experimental evidence that this is a short-term mechanism owing to individual plasticity. Here we experimentally test if house finches (Carpodacus mexicanus) can modulate the minimum frequency of their songs in response to different noise levels. We exposed singing males to three continuous treatments: low–high–low noise levels. We found a significant increase in minimum frequency from low to high and a decrement from high to low treatments. We also found that this was mostly achieved by modifying the frequency of the same low-frequency syllable types used in the different treatments. When different low-frequency syllables were used, those sung during the noisy condition were longer than the ones sang during the quiet condition. We conclude that house finches modify their songs in several ways in response to urban noise, thus providing evidence of a short-term acoustic adaptation.

New Animated Bird Movie--This Spring

Coming this April is a new animated movie, titled "Rio," by the creators of the "Ice Age" movies.

Like the movie "Happy Feet" this upcoming movie uses characters based on real bird species, catchy music, and vivid animation to tell an interesting story and address conservation issues.

The movie focuses on the last two parrots of a species called Blue Macaw in the movie and the need to breed these remaining individuals to save the species from extinction.

It also touches upon the impact that animal smuggling and illegal pet trade can have on bird populations.

The Blue Macaw characters seem to be based on actual species, like the Spix Macaw and the Hyacinth Macaw, which have suffered as a result of illegal pet trade and habitat loss. Fortunately, Hyacinth Macaws have not been decimated to the extremely low levels of the birds in the movie, however Spix Macaws disappeared in the wild in 2000 and around 120 individuals remain in captivity today. It's hoped that captive breeding coupled with habitat restoration will allow for the reintroduction of the birds back into their native habitat eventually.

So go see Rio this April and consider supporting organizations that are helping to save parrot species from extintction.