The acrobatic courtship displays of male Golden-collared manakins (Manacus vitellinus) are less energetically costly than they appear, says a group of ornithologists headed by Dr Julia Barske of the University of California.
Male Golden-collared manakins dance and snap their wings together behind their backs to win the attention of females. These sophisticated routines are performed daily over the Golden-collared manakin’s long courtship season which can last up to 7 months.
Dr Barske and her colleagues set out to investigate how Golden-collared manakins keep up their acrobatic displays – do they live faster-paced, higher-energy lives than other tropical creatures or are their displays less energetically costly than they seem? To determine the energy expended by manakins, they measured the birds’ heart rates.
During courtship performances the scientists found the heart rates of the manikins they monitored rose from around 450 beats per minute to more than 1,000.
These performances each last around 9.5 seconds but the number of performances each bird produces per day varied from 1.6 to 140.
The scientists used this information to calculate how much energy manikins expended on their acrobatic dances, concluding that their performances require on average 0.5 kJ per day, amounting to around 5.2 percent of daily energy expenditure for the most active birds and just 0.1 percent for the least active.
Despite their exuberant courtship displays manakins expend very little of their daily energy on romancing potential partners with acrobatic displays.
The team suggests this could explain why the manakins’ breeding season, which sometimes lasts seven months, can continue for so long whilst the manakins maintain their slow pace of life, typical to animals in the tropics.
The findings have been published in a paper in the Proceedings of the Royal Society B.
Barske J et al. 2014. Energetics of the acrobatic courtship in male Golden-collared manakins (Manacus vitellinus). Proc. R. Soc. B, vol. 281 no. 1776; doi: 10.1098/rspb.2013.2482
This article was first published on Sci-News.com