Toucans outfitted with GPS backpacks are helping researchers track the spread of seeds in tropical forests.
The nutmeg-loving toucan unwittingly plants new trees by gulping whole seeds, processing the soft outer pulp in its crop, and spitting out the hard inner seed. But researchers could only guess how far the seeds would drop from a parent tree.
So conservation biologists from the Smithsonian Tropical Research Institute netted six toucans from a rainforest near Gamboa, Panama, and strapped on lightweight backpacks containing a GPS tracker and an accelerometer. The backpacks recorded location and activity level, and were designed to fall off after 10 days.By matching the roaming data with average regurgitation times from zoo toucans, the researchers calculated that seeds are dropped about 470 feet away from their mother tree. Toucans, they also found, were most active in the morning, followed by a lunchtime lull, with a secondary peak in activity in the afternoon, a common pattern for tropical birds.
“Seeds ingested in morning (breakfast) and afternoon (dinner) were more likely to achieve significant dispersal than seeds ingested mid day (lunch),” write Roland Kays and his colleagues in Acta Oecologica.
The fruit of nutmeg trees typically ripen early in the day, possibly to take advantage of the toucan’s early morning activity.
Top images: 1) Reinhard Vohwinkel, left, and Roland Kays attach a GPS backpack to a wild toucan.
Citation: “The effect of feeding time on dispersal of Virola seeds by toucans determined from GPS tracking and accelerometers.” By Roland Kays, Patrick Jansen, Elise Knecht, Reinhard Vohwinkel, and Martin Wikelski. Acta Oecologica. July 18, 2011.