Why would there be transitional species?
Because evolution doesn't happen in huge multi-gene mutational leaps. C'mon man, you know that!
If Evolution is true, then species are continually evolving ... and if so, there has to be species going from one thing to another ... like ocean to land or land to air .... something .... if you look at every living thing you'd notice they're complete ... a fruit fly will not evolve into an elephant or a rose into a fir tree ...