The Shawshank Redemption
When Andy goes to the library to begin work as Brooks' assistant and Brooks' crow, Jake, is squawking, Tim Robbins had to time his line, "Hey, Jake. Where's Brooks?" so that the crow wouldn't squawk over him, since the bird could not be trained to squawk on cue. Robbins was able to adapt to this and time his line perfectly by learning the bird's squawking patterns, for which Writer and Director Frank Darabont praised him. Robbins' improvisation is noticeable, as he watches the bird carefully while approaching it, waiting for it to squawk, and doesn't begin his line until after it does so.