Bermudez-Cuamatzin, E, AA Rios-Chelen, D Gil & CM Garcia (2009) Strategies
of song adaptation to urban noise in the house finch: syllable pitch
plasticity or differential syllable use? Behaviour 146: 1269-1286.
Abstract:
The influence of ambient noise in shaping birdsong attributes has received
much attention lately. Recent work shows that some birds sing higher-pitched
songs in noisy areas, which may allow them to avoid acoustic interference;
yet it is not clear how this is achieved. Higher-pitched songs may be
produced either by using the same syllable types in quiet and noisy areas,
but singing them at a higher frequency in the latter (syllable pitch
plasticity), or by using different syllable types in silent and in noisy
circumstances (differential syllable use). Here we explored both strategies
in the Mexico City population of house finch (Carpodacus mexicanus), a
species known to possess a repertoire of several hundreds of syllable types.
Birds produced songs with higher minimum frequencies in noisy than in quiet
areas. This was mostly due to the minimum frequency of some syllable types
being higher in noisy areas than in quiet locations. Also, males modulated
the minimum frequency of the same syllable type during momentary increases
of noise. Our results can help explain the high success of house finches at
colonizing urban areas, while providing evidence of syllable pitch
plasticity.
|