WOODPECKERS. 



427 



the highly-developed nuchal crests in many tropical species. A noteworthy structural 

 specialization in several forms, otherwise not intimately related, is the abortion of the 

 first toe, so that only one hind toe remains the fourth. Nevertheless, there are sev- 

 eral pretty well defined groups, or super-genera, under which the numerous species may 

 be advantageously classified. 



Most woodpeckers have the nostrils concealed by tufts of bristly feathers directed 

 forward. In many museum specimens from the tropics these may have disappeared, 

 as the putrefaction which in those countries rapidly sets in first affects the feathers 

 around the bill. But a small group of species, about equally numerous in the tropical 









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FIG. 2J4. Picus virldis, green woodpecker, yaffle. 



regions of both hemispheres, have no bristles where the bill joins the forehead, and 

 the nostrils are consequently fully exposed. Noteworthy among these forms is the 

 South American genus Celeus, the members of which have a very long occipital crest. 

 Some of the Indian species have only three toes, for instance the genus Tiga. The 

 absence or presence of the nasal bristles seems, however, to be of little account, since 

 Nesocelem fernandince, which is confined to the island of Cuba, has the nostrils entirely 

 nude, though' apparently closely related to the following group. 



Our flicker ( Colaptes auratus) and its many allies belong to another group, which 

 are distinguished by having a less typical wedge-shaped woodpecker bill, the angles 

 being more rounded, and the whole bill slightly arched. In regard to the remarkable 



