Juvenile ornamentation in American coots

A study examines ornamentation in juvenile American coots. Ornamental traits, such as bright-colored plumage, are known to benefit courtship and increase mating success in animals. However, the evolutionary advantage of juvenile ornamentation is unclear. To explore links between juvenile ornamentation and evolutionary fitness, Bruce E. Lyon and Daizaburo Shizuka analyzed variations in the brightness, chroma, and hue in the red plumage of American coot chicks between and within brood families. The coots were studied at 5 Canadian wetlands between 2005 and 2008. Coots lay their eggs in each other’s nests, and the plumage of parasitic chicks was a duller red than the plumage of host chicks. The authors posited that parasitic coots do not use ornamentation to dupe host parents into caring for them. The authors found that within families, later-hatched chicks were darker and redder than earlier-hatched chicks. Compared with chicks of the duller hue, redder chicks were more likely to receive preferential treatment and increased portions of food from parents. The findings suggest that ornamentation in juvenile coots allows parents to determine which chicks would benefit most from additional care and nutrition. Further, plumage color may provide cues to the ages and sizes of chicks, according to the authors.

Article #19-13615: “Extreme offspring ornamentation in American coots is favored by selection within families, not benefits to conspecific brood parasites,” by Bruce E. Lyon and Daizaburo Shizuka.

MEDIA CONTACT: Bruce E. Lyon, University of California, Santa Cruz, CA; tel: 831-459-3949; email:

[email protected]

###