Bird travels tracked by fluorescent droppings
Conservationists show use of landscape 'corridors' by bluebirds.
A forest in South Carolina has been peppered with fluorescent bird droppings, all in the name of conservation. The unusual technique was used to track the movement of birds between patches of their preferred habitat after it has been broken up, in this case by stretches of pine trees.
The scientists sprayed wax myrtle seeds, a favourite food of eastern bluebirds (Sialia sialis), with fluorescent powder and then tracked the brightly coloured results.
Their results support the idea that 'corridors' of native vegetation connecting patches of preserved land will direct birds from one friendly area to another. This movement of birds is good news for biodiversity because it means the seeds in their droppings are widely dispersed.
The team's results also imply that it doesn't matter to the birds how wide these corridors are, which may make it easier to plan and construct such connections.
"Corridors make sense intuitively," says Douglas Levey of the University of Florida in Gainesville, who led the study reported in Science1. "But most experiments have been done on a very small scale. It's darn hard to predict what animals will do on a large scale."
University of Florida
When team members examined the fluorescent droppings, they found that most of the birds eating the myrtle seeds flew along the corridor to the connected reserve. This helps to prove that corridors actually work, they say.
The cleared sites were all square, and observers noted that the birds had a tendency to fly parallel to the edges of these cleared areas, rather than flying off in a random direction. Although the researchers didn't get the opportunity to watch the bluebirds actually flying down the corridors, they think that the birds probably navigate along the edges of these too. If so, it doesn't much matter how wide the corridor is, says Levey. "To a bluebird, a corridor is just a pair of edges," he says.
The results suggest that even a narrow corridor could be used to encourage seed dispersal from one area to another, which would help conservationists. The researchers hope that information will be of help to someone, especially as they went to so much effort for the study. "We had to spray tens of thousands of fruits, and look at tens of thousands of poops," says Levey.
- Levey D. J., Bolker B. M., Tewksbury J. J., Sargent S. & Haddad N. M. Science, 309. 146 - 148 (2005).