sue laurance studies the impact of fragmention bird specie dr. sue laurance: birds are very interesting to study the effects of fragmentation -- particularly just the effects of roads because they are highly mobile. they can fly. so a small road of 50 yards or a small clearing really shouldn't inhibit an animal that can fly much greater distances inside the forest. so i caught birds and put little radio receivers on them and moved them across these gaps to see if they can return to what was their home range of their territory. and they know where their home range is because i generally move the male. and the female will be there calling and the male's returning the call. so they know where home is. but they are just not choosing to cross the road at all. and that's a real concern when you can see that some of the clearing patterns that we have seen in the amazon where they have just got long roads could still leave 70% of the forest intact but populations could still be divided by a very small clearing. dr. bill laurance: the roads are in some sen