Hummingbirds as net rate maximisers.

The behaviour of foraging hummingbirds can be accounted for by assuming the maximisation of net rate. The currency, net energy per unit volume consumed suggested by Montgomerie et al. (1984), is shown to be an unnecessary means of interpreting behaviour when compared alongside an extended net rate model. The reason for the failure of previous net rate models to account for observed hummingbird feeding times lies in their negleet of the associated costs outside of the foraging period.