Yes, but rendering a model with individual geometry feathers would probably be rather demanding, the OBJ would be quite large, and depending on the length of the sequence it could take up quite a lot of space on disk. Just something to be aware of.
Honestly unless there is a lot of interaction between your bird-on-a-branch and the Terragen landscape around, or you want to do some big, dramatic camera move away from said bird, you'd probably be better off just creating an environment map in TG3 and using that for lighting and background in another 3D app to render the bird and tree branch.
- Oshyan