Biological Market examples:

Delayed plumage maturation

(from Peterson's Field guide to the Birds East of the Rockies)

Dominant male lazuli buntings select for delayed plumage maturation by only allowing yearlings with female-like plumage access to adjacent high-quality territories


In need of an example to illustrate our ideas Peter Hammerstein and I (1994) made up a story about delayed plumage maturation in purple martins based on data published by Morton and co-workers (see references below). Our idea was that the preference of the dominant 'owners' of martin houses for clearly immature looking subordinate yearling males as subtenants would select for delayed plumage maturation. This would be an example of market selection driving by partner choice in cooperative interactions.

Our purple martin fairy tale in a nutshell

This form of market selection for delayed plumage maturation was later described for another colourful American bird, the lazuli bunting in a great paper by Greene and colleagues in 2000. Dominant lazuli buntings do not determine who occupies nearby nest holes, but who occupies adjacent territories.

  • Greene, E., Lyon, B. E., Muehter, V. R., Ratcliffe, L., Oliver, S. J. & Boag, P. T. 2000. Disruptive sexual selection for plumage coloration in a passerine bird. Nature, 407, 1000-1003.
  • Morton, E. S. 1987. Variation in mate guarding intensity by male purple martins. Behaviour, 101, 211-224.
  • Morton, E. S. & Derrickson, K. C. 1990. The biological significance of age-specific return schedules in breeding purple martins. Condor, 92, 1040-1050.
  • Morton, E. S., Forman, L. & Braun, M. 1990. Extrapair fertilizations and the evolution of colonial breeding in purple martins. Auk, 107, 275-283.
  • Wagner, R. H. & Morton, E. S. 1997. Sexual selection for delayed size maturation in a bird exhibiting delayed plumage maturation. Journal of Avian Biology, 28, 143-149.
  • Wagner, R. H., Schug, M. D. & Morton, E. S. 1996. Confidence of paternity, actual paternity and parental effort by purple martins. Animal Behaviour, 52, 123-132.