Any given species of bird probably has a variety of different songs. Most bird studies track individual birds in their own habitats, and then make more or less one-by-one comparisons—a bird in a forest will sound different from the same species in a city. An international team has taken these studies one step further—by making a giant leap into space.
Thomas Smith, an ecologist at UCLA, and his team from the US, UK, Cyprus, and The Netherlands, found that satellite data, combined with traditional field studies, could help them predict the variations in singing by the common little greenbul (Andropadus virens, pictured), a songbird found in many habitats across Africa. The study, published online in Evolutionary Applications, not only shows how bird songs can vary, but demonstrates how combining satellite data with field studies can trace the evolution and variation of any species. It is also the first study to ever use satellite data to track variation of earth-bound species of animals or plants.
Little greenbuls are found throughout equatorial Africa in all kinds of forest habitats (and there’s plenty of diversity in that region of the continent), making them an ideal bird for this study. Meanwhile, satellite-based sensors are now sophisticated enough to make detailed “pictures” of ecological differences in terrain. So the researchers began recording songs along roads in Cameroon over 10 years, recording more than 2,000 songs from 117 birds. They then combined this data (with detailed records of where the birds where located), with several space-based sensors that measured surface moisture, biomass, elevation, roughness of terrain, photosynthesis activity, and other traits.
The satellite-derived terrain information (in other words, the habitat) explained about two-thirds of the variation in songs of the little greenbul. Variations in frequency and amplitude of song were explained largely by the type of terrain. Birds singing in rain forests were particularly unique. The team then found that they could predict bird songs in other areas of Africa they hadn’t tested, including Equatorial Guinea, Gabon, Republic of the Congo, and the Central African Republic.
Making this close a link between bird behavior (or any behavior) and the terrain (including human development) can help create more effective conservation programs, the researchers suggest.
Photo: Wikimedia Commons
Smith, T., Harrigan, R., Kirschel, A., Buermann, W., Saatchi, S., Blumstein, D., de Kort, S., & Slabbekoorn, H. (2013). Predicting bird song from space Evolutionary Applications DOI: 10.1111/eva.12072
how a bird learns songs, research on birds evolution