Our results seem to be at variance with earlier studies on
flexible individual roles in pigeon foraging flocks. Both theoretical
(Giraldeau 1984) and empirical work (Giraldeau and
Lefebvre 1986, 1987) suggest that pigeons in groups have
flexible producing specialisations that change from one feeding
situation to the next, yielding a skill pool when each bird
can scrounge the specialisations of others on tasks where
it has not learned to produce. In both the theoretical and
empirical work, producing specialisations are uncorrelated
across individual pigeons over different tasks. In the skill
pool hypothesis (Giraldeau 1984), it is the chance effect of encounters with food rewards that determines who learns in
any given situation, added to the incompatibility between
producing and scrounging and the inhibitory effect of group
scrounging on learning (Lefebvre and Helder 1997). Our
finding that performances across learning situations are positively
correlated thus differs from the zero correlations envisioned
by the skill pool. More work is needed to reconcile
these differences, but one intriguing possibility is that the
frequency-dependent payoffs that act in a group situation
override the individual differences that show up in single
cage experiments like ours. Such a finding would support
the point made by Giraldeau and Caraco (2000) for learning
and Morand-Ferron et al. (2004) for innovations, that
frequency-dependent payoffs can be more important than individual
abilities in determining whether or not a behaviour
will occur in a given social foraging situation.