The mist is beginning to disperse, allowing a few patches of blue sky to peep through. It is the beginning of a fine morning on Montagne Trésor, a few peaks along from Montagne de Kaw in the French Guianese mountain chain of the same name. Gradually the concert of birdsong greeting the sunrise dies down and the forest becomes calm once again. Suddenly the walkie-talkie crackles into life: “Table, calling table, net number 37 here, we have a control.” “Table here, go ahead". J “R47 521, a PIP ERY.” “OK, I've got it. It's a bird we ringed this morning. You can release it." Searching for the ringed bird The bird is free once more and rapidly disappears from the view of the ornithologists, who immediately resume their laborious way struggling through the undergrowth. But what are they looking for? It's not easy to explain but, to put it simply, you could just say they are trying to find out more about the forest birds in the territory. A first in South America This scientific study into the biology of the forest passerines of French Guiana started in June 2007 in the Trésor Regional Nature Reserve. It was set up on the initiative of the bird-ringers working for the CRBPO (Centre for Research into Bird Populations by Ringing, part of the National Museum for Natural History in Paris) and the reserve, with the support of GEPOG (Group for the Study and Protection of Birds in French Guiana). This standardised study is called the STOC-Trésor Programme ......