TECHNOGENIC NOISE AFFECTS THE MINIMUM FREQUENCY OF CHAFFINCH SONG COMPONENTS (FRINGILLA COELEBS) IN THE MOSCOW POPULATION

To test the hypothesis that birds shift song parameters to higher frequencies at a permanent low-frequency noise, we received records of 78 chaffinch male vocalizations in Moscow city parks. The levels of noise were also recorded for each phonogram. We measured the minimum frequency of 4 phrases in 3 common song types in Moscow. Measurements of each phrase were made in 18-21 males, including 4 randomly selected songs with a phrase of this type in each male. The minimum frequency of phrase 1 in the different male vocalizations varied from 4.94 to 5.22 kHz, phrases 2 from 2.23 to 2.6 kHz, phrases 3 from 1.77 to 2.64 kHz, and phrases 4 from 2.08 to 2.42 kHz. A reliable positive correlation (Pearson coefficient 0.67 < r < 0.79 for all phonograms) of the minimum frequency with the noise level was revealed for 3 of the 4 studied phrases. A sharp increase in the minimum frequency of singing with increased noise was revealed at or above a noise level of 55 dB.