I haven't got the "tail nibbler" No. 15 but have the other 2.
17. Look for the genus of a well known, noisy black and white bird who annoys and frightens small birds.
45 First 2 letters come from THE in clue. The last 6 is the plural of a well known usually tallish water plant. Often with the name of a large male animal first - 4 letters - related to the cow!!!!
Re the "tail nibbler". Have seen the suggestion of "motmot" and French but doesn't mean anything to me although motmot is a bird.