In Doncaster, Tristan introduces his trainees to a mule — rarely seen in England but an important part of the war effort abroad — and quizzes them on the animal. “Give that man a coconut,” he exclaims when a correct answer about colic is given. However, his superior officer, Major Robertson (Adam Best), has another assignment for him. The army is to train a crack team of homing pigeons (invaluable messengers during WWI), and Tristan is to find birds. Yorkshire is apparently a hotbed of pigeon breeders, so it should be an easy task, or so one would think, and he’ll be home for Christmas.
Tristan begins his search for Yorkshire’s top pigeons with a visit to Enoch Sykes (Duncan Preston) who is tending his birds in his backyard. He is not friendly and throws some pigeon debris at Tristan to make his point. But Tristan notices the pigeon poop has an unusual green tinge, which could be a parasite, and Enoch begins to take him seriously. He grudgingly allows Tristan to take a bird who’s been showing signs of ill health back to the office for testing.
Unfortunately, the pigeon is dead on arrival. James and Siegfried consult books and decide a pigeon post-mortem is in order, but it’s so delicate and fiddly they send the corpse off to the lab. Tristan doesn’t tell Enoch Sykes, who understood the bird would be kept overnight, and after a week, he phones the surgery. Tristan, nervous of Enoch’s reaction, pretends to be Siegfried on the phone, and hangs up. It’s not his finest hour. But when Enoch arrives at the surgery, Tristan has to come clean and tells him he’s waiting to hear from the lab. With commendable dignity, he tells Tristan he’s warned other breeders about him, and meanwhile, two other pigeons have died.