the flight trajectory of stage birds

From a recent email from an old friend:

Someone I work with told me that there was a very high-profile stage production of The Sound of Music in the 1960s, for which the director wanted to release a flock of birds at the end of the song "Climb Ev'ry Mountain," when the soprano hits the climactic final high note. Unfortunately the set designers and production team placed the holding cage for the birds too high up and too close to the hot lights, and the birds were broiled. When the soprano hit the high note at the end of the song and the backstage crew pulled the cord to open the cage, instead of taking flight, hundreds of dead birds free-fell in a heap onto the middle of the stage.