A new study has revealed that
researchers have discovered that songbirds with flashy feathers called red-backed fairywrens weren’t molting into their extravagant black and red plumageafter the destruction of their habitats by wildfires throughout Australia.
1 The less appealing feathers were also associated with an increase in testosterone which is associated with the flashy plumage. The attractive feathers are what help attract their friends. 1
The study was conducted by researchers
who determined the levels of the stress hormone corticosterone as well as their fat stores. However, the levels remained steady. The testosterone level was altered following the fire. 1Really the result was everything being about the hormone testosterone” is the lead study author Jordan Boersma, a doctoral student at Washington State University. “There’s no evidence to suggest that the birds were stressed. birds facts
Wildfire just interfered with their normal rhythm of boosting testosterone levels and resulting in that beautiful plumage.”Male red-backed fairywrens are the most common to change their color, changing from their normal white and brown plumage, to flashy reddish orange and black just before the breeding period. 1
“This transition from dull to ornamented
plumage is helped by the increase in testosterone levels which lets males sequester the carotenoids they consume into bright red colors on their backs (less is information available about the process by which black plumage is created, however testosterone could be at play),” Boersma tells Treehugger.
What Testosterone is a Player
In the study, which is published in Journal of Avian Biology Researchers observed the behaviours and collected samples of fairywren’s blood for five years in two distinct locations in the northeast of Queensland state in Australia.
months since it’s likely not suitable
Researchers have found that following the wildfires, less ornamentation appeared to be due to male birds not producing more testosterone like they do prior to the typical breeding season.
“Collectively it is possible that fairywrens could protect against adverse effects on your personal health and life by keeping testosterone at a low level and retaining a dull color in the event that breeding is hindered and/or delayed” Boersma says.
“Remaining dull could mean that males weren’t
prepping for the breeding season, but it’s likely that they’ll find a partner in a less vibrant state. This means they’re less attractive to mating partners from outside the pair as this is a significant element of fitness for this species.”
The findings of the study are unique to the tropical songbird however, they may be applicable to other species with particular colors or designs before the breeding period. 1
“It might be a good method of determining the health of a population when you know their typical degree of appearance,” Boersma says. “If you find that there are a few males who are going through that change, then there’s most likely something about the surrounding environment that’s not optimal.”