Birds of a Feather was definitely one of the better episodes, I think. I really enjoyed Philip Abbot's work - a bad guy without all the comic-book stereotyping that is so frequent on this program.
The plot seemed to have some holes in it. Jonathan gets Mark to find a job at Drake so he could dig up info about toxic waste dumping. Then barely 15 minutes into the episode, Jonathan is riding around in his bird suit accusing Drake of causing the polluted water that's killing the seagulls. The episode never shows Mark passing to Jonathan any credible proof that Drake was actually the cause of the water pollution. Like the CEO said - and credibly so - Drake is not the only plant in the area.
Also, Jonathan surprises Rita when he tells her that Dr Sweeny got a payraise. If Jonathan can figure that out on his own, how come he needs Mark to find out if Drake is illegally polluting the water?
The two kid actors, Gino De Mauro (Richie) and Paul Walker (Eric) almost looked like brothers even though their parents are different.