Simple dichotomous key illustrating bird beak features to identify species like Certhidea, Geospiza, Camarhynchus, and Platyspiza.
A simple dichotomous key for identifying birds based on beak characteristics, showing illustrations of four birds (W, X, Y, Z) and a decision table with options for Certhidea, Geospiza, Camarhynchus, and Platyspiza.