Extracted from Harry Potter: The Creature Vault by Jody Revenson
At Hogwarts, the Owl Post brings letters and packages from home, newspapers, and any other object needed to be delivered to a student. In Harry Potter and the Philosopher’s Stone, Neville Longbottom receives a Remembrall. Ron Weasley catches a Howler in Harry Potter and the Chamber of Secrets. And throughout the Harry Potter films, Hermione Granger gets her subscription to the Daily Prophet via owl.
The owls seen in the majority of Harry Potter films ranged in size from the smallest of species to the largest, weighing between three and a half ounces (Sunda scops owl) to five and a half pounds (European eagle owl). Sixteen owls were trained in several ‘behaviours’ for the various tasks needed by the Owl Post, each owl accompanied by a trainer. The variety of breeds included great greys, barn owls, snow owls, and tawny owls, as different breeds have different physical wing structures in order to take advantage of their environment. Large owls are typically better at soaring, thanks to their bigger wings. Small owls are better hoppers.
The real-life owls did not actually carry the packages and letters in their talons. These props were tied to a light plastic harness that was placed over the bird’s body. The harness had a release mechanism on it, attached to a long invisible cord that was held out of sight by a trainer. When the owl was required to drop its item as it flew toward its mark, the trainer would trigger the mechanism to open and the delivery would be made. Because larger owls can prey on smaller ones, any scenes with multiple live owls would be filmed with only one or a few and then composited together.
Although we think of owls as nocturnal creatures, they actually hunt around the clock, so they are easily adaptable to work in the daytime. The owls trained for the Harry Potter film series were accustomed to working on a daytime schedule, though they did take naps from time to time. With a few exceptions, the owls used in the Privet Drive sequence in Harry Potter and the Philosopher’s Stone were faux—either owl models or computer-generated owls.
The majority of owls in cages at the Hogwarts Express station were also models, including a Hedwig stand-in. Any live owl used in the scenes loading or unloading onto the train would have its cage bolted to the luggage cart. Whenever a live owl was used, it had a light, invisible safety line attached to it, even while it flew. Sixty live owls were featured in the Owlery scene of Harry Potter and the Goblet of Fire, which utilised even more faux owls, some mechanical. Many of the Owlery owls were borrowed from rescue centres.
‘Wise old owl’ is a common myth but owls are actually not the fastest of learners. Once they do learn a behaviour, fortunately, it becomes firmly ingrained, and so it was not difficult to bring the owls up to speed upon returning to each film. The owls responded to a whistle sound that was part of their training to turn their heads on cue or to fly from point A to point B, where they would be rewarded with an owl treat.
For use in the background, or to populate a scene, some owls were held by their trainer and filmed flying in front of a wind machine set up against a green screen. The trainer would be digitally removed and the filmed owl could then be directed within the computer to fly in any direction necessary and as high and faraway as needed for long shots.