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STUDENTS AND POST-DOCS

BRANTA — Robert P. Clay


Correlates of male status in the Long-tailed Manakin Chiroxiphia linearis (Aves: Pipridae)

Institution: University of Cambridge, UK
Supervisors: T Clutton-Brock
Details: PhD 2001 (Completed)

Address: BirdLife International, Vicente C├írdenas E5-75 y Japón, 3er Piso, C.P. 17-17-717, Quito, Ecuador (Apr 2006) Email

Subject Keywords: Lek, co-operation, delayed plumage maturation, dominance queues, male condition, status signalling
Species Keywords: Long-tailed Manakin Chiroxiphia linearis

 

Abstract

Lek mating systems, in which males aggregate at traditional sites to display for females that attend primarily for the purpose of fertilisation, are characterised by large inequalities in male mating success, and intense competition between males. It seems paradoxical, therefore, that males of one genus of lek mating manakins, Chiroxiphia (Aves: Pipridae), cooperate in dual-male displays for females. The benefits of this cooperation appear virtually unilateral, especially as males are not closely related. Instead, benefits to subordinates are offset in time, and relate primarily to ascent to dominance status.

I studied the behaviour of Long-tailed Manakins Chiroxiphia linearis at a long-term study site at Monteverde, Costa Rica, to investigate the physiological control of delayed breeding in subordinate males. The results presented here form a background to that study, and address issues relating to the roles of inter- and intrasexual selection in determining male mating success, the reproductive strategies employed by males, and the role of plumage in the establishment of dominance. Methods included the monitoring of male displays and female visitation at nine primary leks, and the gathering of morphological and plumage data, and blood samples from captured birds. Male mating success was determined by a combination of intra- and intersexual selection. Males at each lek form an orderly queue for dominant status, which among top-ranking males is linear. Only the dominant male, with rare exceptions, had access to mating opportunities. Females appear to discriminate between male queues on the basis of dual-male phenotypes relating to display performance. The cues used by females may provide reliable information about the quality of the dominant male in each queue. Queues appear to be stable because subordinate males have a high probability of ascent to dominant status. However, when subordinates are unable to accurately predict their survival probability relative to dominant males, queue order deteriorates, and dominant males may have to concede some reproductive opportunities. Young males move through three age-specific predefinitive plumages that act as broad signals of status. Individual variation within each plumage class appears to be condition-dependent, and may fine tune the status signal.

 

Published Papers

Doucet, S.M., McDonald, D.B., Foster, M. & Clay, R.P. in press. Plumage development and molt in Long-tailed Manakins, Chiroxiphia linearis: variation according to sex and age. Auk in press.
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