The Auk 117(2):465-478, 2000

DISPLAY BEHAVIORS, MECHANICAL SOUNDS, AND EVOLUTIONARY RELATIONSHIPS OF THE CLUB-WINGED (MACHAEROPTERUS DELICIOSUS)

KIMBERLY S. BOSTWICK • Departmentof Ecologyand EvolutionaryBiology and Natural HistoryMuseum, Universityof Kansas,Lawrence, Kansas 66045, USA

ABSTRACT.--MaIeClub-winged (Machaeropterusdeliciosus) are known to pro- ducea uniquemechanical sound with their extremelymodified secondary feathers, yet the speciesremains poorly known behaviorally. I observedlekking males in ReservaMaquip- ucuna, Pichincha Province, Ecuador, to better understand the role of mechanicalsounds, the behavioralrepertoire, and otherdetails of the naturalhistory of thisspecies. The behavioral repertoireof M. deliciosusis much more diverse than previously documented; it includesfour mechanicalphrases, two vocalsounds, and seven display behaviors. Mechanical sounds con- stitutethe mostprominent elements of the species'displays, replacing vocal sounds for ter- ritorial advertisement.I examine possible homology of the observedbehaviors and propose a newphylogenetic hypothesis, that Machaeropterus forms a monophyleticclade with thege- nusPipra, based on theexistence of a complexshared courtship display. Received 20 July 1998, acceptedI October1999.

THEFAMILY PIPRIDAE, the Neotropicalman- soundsproduced by structuresother than the akins, is a clade of approximately40 sexually syrinx and used for the purposeof communi- dimorphiclek-breeding species (Prum 1992). cation(Prum 1998).The productionof mechan- The bright plumagesand elaboratedisplays of ical sounds,although common in manakins,is male manakins have attracted considerable at- relatively rare in as a whole, and Club- tentionover the last century(e.g. Snow 1963b, winged Manakinsproduce mechanical sounds Sick 1967,Prum 1990).Surprisingly, however, that are acousticallyunique (Prum 1998).The displaysof mostspecies in the family havenot lack of detailed behavioral information has hin- beenobserved or describedin detail,and many dered our understandingof the evolutionand are known by little more than anecdotalde- physicalmechanics of this unusual mode of scriptions(Prum 1990, 1996). communication. The Club-wingedManakin (Machaeropterus Althoughconsidered the best-known species deliciosus)is endemic to humid forests of the in its (Prum 1990), current behavioral western slopesof the Andes in southwestern descriptionsof Club-winged Manakins are in- Colombia and northwestern Ecuador (Hell- complete. Willis (1966) and Orejuela et al. mayr 1929, Hilty and Brown 1990). Like most (1982) reporteda display in which the wings other manakins,they are sexuallydimorphic. are thrown open and mechanicalsounds are Femaleshave drab olive-greenplumage, and produced.Willis (1966) noted that the wings males have a chestnut-coloredbody, a red produce the unusual mechanicalsounds, but crown,and wings that are white ventrallybut he did not observethe behaviorin any detail. black dorsallywith peculiarwhite, thickened Indeed, the rapid and brief nature of the dis- shaftson the secondaries(Orejuela et al. 1982, playsmake them extremely difficult to describe Ridgely and Tudor 1994). withoutthe aid of video.Orejuela et al. (1982) Darwin (1871) described the secondary made extensive observations of habitat and lek feathersof male Club-wingedManakins as an characteristicsand discussedthe evolutionary example of structural modificationsfor pro- importance of lek-breeding in this species. duction of "instrumental music," or mechani- cal sounds. Here, I use the term "mechanical They alsodescribed the mechanicalsound dis- play in more detail, as well as a vocalization sounds" to mean intentionally modulated and copulatorybehaviors. However, details necessaryfor understandinghow the mechan- E-mail: [email protected] ical soundsare producedwere lacking. Neither

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