The “Coerebidae”: a polyphyletic taxon that dramatizes historical over‐emphasis on bill shape as a taxonomic character

Because the core body shapes of birds are relatively conservative (Hafner et al. 1984), differences in bill shape and size account for much of the variation among birds that we humans perceive. Although tail and leg size and shape may vary almost as much, the bill may exert more influence on our cognitive perception because of its proximity to the bird's face. The close association of bill size and shape with food type and feeding behavior adds additional weight to the ornithologist's perception of their "importance." For these reasons, it is perhaps no surprise that bird bills have played a prominent role in their classification.