That's the title of a paper in a recent issue of Nature Neuroscience:
http://www.nature.com/neuro/journal/v12/n7/abs/nn.2336.html
The full article requires a subscription.
They put headphones on their experimental subjects (Bengalese finches) to give them pitch-shifted feedback about their own singing, and found the birds adjusted their performance in the opposite direction.
Actually, according to their numbers, the birds didn't fully compensate (i.e. maintain their pitch perception constant), as a 100 cent (6%) upward shift resulted over a 2-week period in only a 50% downwards shift in the birds' performance. As a control system, either it has rather low gain, or it takes longer to act than the experimenters allowed. After the distorted feedback was removed, the birds took 67 days to return to baseline performance. I also wonder what feedback the birds get through internal conduction instead of their ears, which the headphones wouldn't affect.
Anyway, here is their description of what they are doing, and their comparison with previous work on adult birdsong:
"Here, we tested the hypothesis that, similar to humans, birds maintain adult vocal output by comparing auditory feedback to a long-lived auditory target and using the resulting error signals to adaptively modify their vocalizations. This type of error-corrective mechanism requires several things of the adult song system. First, there must be a stable auditory target representing the desired song output. Second, adults must detect small differences between auditory feedback and the target and evaluate which changes in motor output reduce the sensory error. Third, the motor program for song must be modifiable. The first two requirements define error correction, whereas the third merely asserts that the song system is plastic in adulthood.
[RK comment: First: reference; second: perception and error; third: output.]
"Manipulations that corrupt or completely eliminate auditory experience (via distortions of auditory feedback or deafening) have been shown to drive degradations of crystallized song, demonstrating the potential for vocal plasticity in adulthood and showing that the third condition is satisfied. Furthermore, differential reinforcement signals provided by an external evaluator can drive directed changes in adult song. To our knowledge, however, no prior studies have shown that adult birds naturally perform error correction by monitoring song output to detect and correct deviations from an auditory target. Deafening and feedback distortion procedures presumably create a mismatch between auditory feedback and the sensory target, but provide no opportunity for the bird to correct these errors, as no alteration of vocal output can restore normal auditory feedback. Reinforcement procedures circumvent error detection entirely by rewarding or punishing birds on the basis of the experimenter's (rather than the bird's) evaluation of vocal performance. A true test of adult error correction therefore requires an experimental procedure in which birds both detect song errors and modify their vocal output to reduce them."
···
--
Richard Kennaway, jrk@cmp.uea.ac.uk, http://www.cmp.uea.ac.uk/~jrk/
School of Computing Sciences,
University of East Anglia, Norwich NR4 7TJ, U.K.