In our experiments we measured the seed husking time
and the maximal bite force of two taxa of seed cracking
birds. Husking time is related to maximal bite force in a
highly non-linear way and differs between estrildids and
fringillids. Fringillids with the same bite force as estrildids
take less time to crack seeds, but only when the strength of
the seed coat is close to their maximal bite force. For seeds
that are relatively soft the difference in husking time
becomes very small. A preliminary jaw motion analysis
provides evidence that this difference in husking time
between estrildids and fringillids is paralleled by a
difference in husking technique. This difference in
technique does not affect bite force as such, but decreases
the chance of failed cracking attempts.