Have you ever had noticed that urban birds sing longer than countryside birds? Well it appears that there is an explanation for this. A study published in the March-April issue of the journal Behavioral Ecology explains that urban birds increase the amount of time they spend in vocal activities in order to compensate for the negative effects of human noise, especially the noise caused by city traffic. The research was conducted through the European serin (a small bird closely related to the canary), which inhabits lands around the Mediterranean Sea, Central Europe and North Africa. The European serim can spend up to 60% of its time singing if the level of the city noise reaches 70 decibles (dB). On the other hand, if the city noise becomes higher than this level, the percentage of the Europeans serins effort starts to diminish, partly because this could negatively influence the European serins other functions such as spending some time monitoring the environment, whereas while singing they are less aware of predators or the arrival of competitors. Researchers also concluded that birds nesting in areas that are noisier by day tend to sing more at night. Other functions of the singing are to attract females and deter potential competitors. It also involves the recognition of dialect within species, allowing birds to stay in touch with their own kind.