The book that DI Humphrey Goodman is seen reading at the police station is 'Birds of the West Indies' (4th ed.) by James Bond. This was the author after whom Ian Fleming named his world famous spy (Fleming had a copy of the book at his home in Jamaica).
D.I. Goodman (Kris Marshall) foreshadows this episode by reading from a travel guidebook in episode #3.3, An Artistic Murder (2014), "the fabled Saint-Marie green..." but trails off before finishing the sentence.
There are subtle references to other shows and movies:
Pirates of the Caribbean: Captain Jack Parrot (Paul Barber) instead of Captain Jack Sparrow
Monty Python: The St. Marie Green instead of the Norwegian Blue
Monty Python: The Dead Parrot sketch at the end of the show
Ian Fleming/James Bond: D.I. Goodman (Kris Marshall) reading Birds of the West Indies
Angry Birds (2009): Catherine (Elizabeth Bourgine) saying, "that was one Angry Bird" at the end when the gang was at the bar.
Ciarán McMenamin was on Primeval as Matt Anderson (Series 4 & 5 ). Ben Miller ( Richard Poole) also starred as James Lester on Primeval (Series 1-5)
The term for a bird watcher is 'ornithologist'. Although the episode was about a group of ornithologists, the term is not used.