QuickTime files


Alarm calls Click the still frame at right to download a QuickTime video clip (4.5 Mb) showing the response of a male to a computer-generated hawk animation. The stimulus, which was presented on a large video monitor mounted above the cage, is visible in the small 'window' in the top left-hand corner of each frame. The male crouches slightly, rolls his head to fixate with one eye, and produces a series of three aerial alarm calls. Simple animations of this kind reliably evoke the full range of vocal and non-vocal responses to avian predators. We have taken advantage of the flexibility afforded by computer animation techniques to explore the effects of manipulating predator morphology and behaviour. Production of aerial alarm calls is dependent upon the apparent size, speed, shape and spatial location of a simulated raptor.
Click the still frame at right to download a sequence (6.5 Mb) showing the response to a videorecorded raccoon. The male was shown a 60-second sequence of a life-sized raccoon, which was displayed on a monitor at ground level on the right-hand side of the cage. Only the first 15 seconds is shown to reduce file size. The predator stimulus is visible in the small 'window' in the bottom right-hand corner of each frame. Notice the contrast in the male's behaviour compared with the 'hawk' sequence above. The erect posture, increased activity and slow pulsatile calls are all characteristic of the initial reaction to a ground predator.
Food calls Recent experiments on food calling have concentrated on the responses of signal receivers. Click on the still frame to see the effect of a bout of tape-recorded food calls (4.9 Mb). The hen approaches the loudspeaker, which is behind a screen at the right-hand end of the cage, and begins looking downward and pecking at the substrate. These anticipatory feeding movements are much more frequent when food calls are presented than when the hens are played either ground alarm calls (which are structurally similar), or contact calls (which are produced under similar social circumstances).

Alarm calls

Click the still frame at right to download a QuickTime video clip (4.5 Mb) showing the response of a male to a computer-generated hawk animation. The stimulus, which was presented on a large video monitor mounted above the cage, is visible in the small 'window' in the top left-hand corner of each frame. The male crouches slightly, rolls his head to fixate with one eye, and produces a series of three aerial alarm calls.
Simple animations of this kind reliably evoke the full range of vocal and non-vocal responses to avian predators. We have taken advantage of the flexibility afforded by computer animation techniques to explore the effects of manipulating predator morphology and behaviour. Production of aerial alarm calls is dependent upon the apparent size, speed, shape and spatial location of a simulated raptor.

Click the still frame at right to download a sequence (6.5 Mb) showing the response to a videorecorded raccoon. The male was shown a 60-second sequence of a life-sized raccoon, which was displayed on a monitor at ground level on the right-hand side of the cage. Only the first 15 seconds is shown to reduce file size. The predator stimulus is visible in the small 'window' in the bottom right-hand corner of each frame. Notice the contrast in the male's behaviour compared with the 'hawk' sequence above. The erect posture, increased activity and slow pulsatile calls are all characteristic of the initial reaction to a ground predator.

Food calls

Recent experiments on food calling have concentrated on the responses of signal receivers. Click on the still frame to see the effect of a bout of tape-recorded food calls (4.9 Mb). The hen approaches the loudspeaker, which is behind a screen at the right-hand end of the cage, and begins looking downward and pecking at the substrate. These anticipatory feeding movements are much more frequent when food calls are presented than when the hens are played either ground alarm calls (which are structurally similar), or contact calls (which are produced under similar social circumstances).

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