Every spring, migratory birds like the Black-throated Blue Warbler journey from tropical Caribbean or South American refuges to North American forests. But which forest patch will they call home this year? And, how can researchers predict where they choose to nest?
Ecologists studying biodiversity and conservationists preserving habitats have asked these questions for more than 50 years, but with limited and imprecise means to answer them. Now a team of NASA-funded researchers has completed an experiment to remotely sense and predict where certain birds are most likely to live and breed.
In the late 1950s, Princeton University ecologist Robert MacArthur proposed that bird species choose their habitat according to the structure of a forest that is, the tree canopy height, branching structure, leaf spread and abundance, and the presence of low-lying shrubs.
To determine the habitat where particular species bred, ornithologists trekked deep into forests and used everything from binoculars to suspended vines to observe leaves and twigs and extrapolate the make-up of forest areas. They could spend thousands of painstaking hours analyzing plots as small as 100 square feet. As recently as May 2010, an Oregon State University doctoral student dislocated her shoulder while using a rudimentary pole to demonstrate how scientists once measured tree branches from the ground -- and to show how and why the science of studying birds has changed.
"Most of the time, the data weren't very good, and didn't cover broad areas of land," said landscape ecologist Matt Betts, an assistant professor at Oregon State University in Corvallis.
A research team led by Scott Goetz of the Woods Hole Research Center in Falmouth, Mass., has helped bring habitat sensing into the 21st century. The researchers combined satellite data, a ground-based bird census, light detection and ranging (lidar), and a new modeling technique to correctly predict the p
|Contact: Sarah DeWitt|
NASA/Goddard Space Flight Center