Figure 2.

Assortative pairing by beak size in pairs of G. fortis at El Garrapatero. (a) A breeding pair of small morph individuals (photo credit Eric Hilton) and (b) a breeding pair of large morph individuals (photo credit Sarah Huber) photos not to scale. (c) Assortative pairing under dry conditions (2004, early 2005). (d) The pattern under very wet conditions (late 2005) and (e) the pattern under moderately wet conditions (2006). Male and female ‘beak PC1’ values are scores along the first principal component based on beak length, depth and width.