The repertoire of a male yellow-headed songster of the forest becomes more diverse, if the forest in which they live, for the last ten years suffered from a fire. This is the conclusion reached by ornithologists, examining singing 1588 males across California. In an article for the journal The Auk , the authors assumethat the forest fires forced the songstress to actively settle. As a result, the speakers of different dialects are mixed, and a General variety of songs is growing.
Ornithologists have long noted that environmental changes have a major impact on the birds singing. For example, the types who mastered the city have to adjust their songs to a high level of urban noise. A sharp decline in the Hawaiian flower girls (Drepanidini), which is caused by species introduced by people, significantly emasculated their repertoire.
A team of researchers headed by Brett Furness (Brett J Furnas) from the California Department of fish and wildlife decided to find out how to affect the birds singing forest fires. They focused on the yellow-headed forest songster (Setophaga occidentalis) is a small passerine bird from the family of drevesnitsa (Parulidae) that breeds in forests in the Western United States.
Males of this species sing the songs of two different types, one of which serves to attract females and one for marking territory. Interestingly, the first type is extremely uniform: the majority of males in a particular area sing very similar songs of the first type, while the set of songs of the second type can differ from individual to individual.
From 2009 to 2014, the researchers recorded the singing males 1588 citrine forest songbird in 101 point throughout California. They were interested only in the songs of the first type. The analysis allowed to divide them into 35 dialects, each of which was characteristic of the subpopulation of forests of a certain type. For example, dialects A3, A4, B1 and B2 dominate the forests of Redwood trees (Sequoia sempervirens). According to the authors, the differences between dialects are not linked to the acoustic characteristics of different forests. Rather, they reflect the strategy of obtaining food from living in them birds.