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Jonathan Wagner wrote: 

>                +-Dromaeosaurs    +-Tyrannosauroidea+Ornithomimoidea
>        +-------+MANIRAPTORIFORMS |
>        |       +-----------------+ARCTOMETATARSALI(=Bullatosauria(?))
>        |                         |
>--------+COELUROSAURIA            +-Troodontidae
>        |
>        |       +-Caegnathidae
>        +-------+OVIRAPTORSAURIA
>                |
>                |  +-Elmisauridae
>                +--+
>                   |  +-Alvarezsauridae
>                   +--+
>                      +-Therizinosauroidea+Compsognathus

 From what I've seen in some recent articles, I think some 
paleontologist are thinking more in line like this. (Don't quote me on 
it though)

        |        |
        |        |  +-Elmisauridae
        |        +--+
        |           |  +-Alvarezsauridae
        |        +-Dromaeosaurs   
        |+-------+MANIRAPTORIFORMS |
         |            |
--------+COELUROSAURIA            +-Troodontidae

Also I was thinking today about why the 'proto' bird would climb a 
tree. Two things came to mind, frist, what ever the 'proto' 
bird/archosauromorph was chasing, a diapsid or some what, ran up a tree 
trunk, the chaser either would watch it climb a tree, or try to climb 
the tree. Finding it advantagous, the chaser climbs the tree after the 
chasee. Later, the chaser might have found it even more advantagous up 
the tree, while the others ran around on the land. Or 2, its the 
chasee, is the one who became the bird line. Take either way for your 
cladagram branch for bird evolution. 

If the prey is faster on land, alls the predator would have to do is to 
be faster, not start flapping, then gliding. Unassisted flight, ie 
gliding, would be slower than a contued run. Weither your the chaser or 
the chasee.