Hummingbird Research

Learned song is found in three groups of birds: oscine songbirds, parrots and hummingbirds. Both oscine songbirds and parrots comprise avian groups in which all species appear to have vocal learning. The hummingbirds are unique, in that some hummingbirds learn song, while others appear to lack this ability.  Vocal learning has been studied extensively in the oscine songbirds, which are the basis for current ecological and evolutionary models of bird song.  These three groups are separated from each other by orders of vocal non-learners, and the current orthodoxy hypothesizes that vocal learning has independently evolved in each order. Alternatively, it is possible that learned song has evolved only once, and has since been lost multiple times in the intervening taxa.

Southern California’s diverse fauna of hummingbirds is an exceptional system to distinguish between these opposing models of the evolution of song.  My research focuses on two local congeneric species, one with complex, learned song (Anna’s) and the other with simple, innate vocalizations (Costa’s, although it has scarcely been studied).  Our research to date provides field confirmation that Anna’s hummingbird has learned song (Steen & Houtman in preparation; Schwiebert & Houtman in revision) and that Costa’s hummingbird has simple vocalizations with no evidence of song learning (Williams & Houtman revised & resubmitted). Furthermore, males of the two species are using song in quite different ways and quite differently from oscine songbirds (Anduri & Houtman in preparation; ongoing research with English, Castro, Williams and Tran).  We expect that this work will eventually provide strong support for multiple loss of learned song causing the phylogenetic pattern of vocal learning we see in birds today.