An adaptive modification in the ribs of woodpeckers and piculets (Picidae)

Publication Type:

Journal Article

Authors:

Kirby, Virginia C.

Source:

Auk, American Ornithologists' Union, Volume 97, Issue 3, p.521-532 (1980)

Call Number:

A80KIR01IDUS

URL:

https://sora.unm.edu/node/23433

Keywords:

Piculet, Woodpecker

Abstract:

Woodpeckers and piculets (Picidae) exhibit a pronounced broadening of the first thoracic rib at the articulation between the vertebral and sternal portions of the rib. In addition, the last cervical rib is enlarged, as are the vertebral attachments of both these modified ribs. The mean ratio of the first sternal rib width to femur length (×100) for 89 species ranges from 2.9 (Jynx torquilla) to 14.8 (Picoides tridactylus). The Jynginae have noticeably lower rib to femur ratios than the rest of the Picidae. Complexity in the musculature of the anterior ribs also increases from Jynx torquilla through Colaptes auratus to Picoides villosus. These increasing ratios parallel an increase in the specialization of skull structure for pounding behavior. A survey of the foraging modes employed by 61 species shows that genera containing species that excavate frequently have higher rib ratios than genera whose species primarily glean and probe. Woodpeckers that pound frequently and hard require a more highly developed musculature at the base of the neck to provide the strength needed to pull the neck forward and down in blow delivery and to stabilize the neck against the resulting impact.