Birds may have evolved head feathers as sensory device
London: In a new research, scientists have suggested that birds may have evolved elaborate feathers first for touch sensing, with sexual selection coming later.
According to a report in New Scientist, the research was carried out by Ian Jones of Memorial University in St John’s, Newfoundland, Canada, and Sampath Seneviratne, now at the University of British Columbia in Vancouver, Canada.
Crested and whiskered auklets nest in hollows on rocky islands in the remote northern Pacific Ocean.
To see if their elaborate headdresses helped the birds make their way through the rocks to their nests at night, Jones and Seneviratne went to the Aleutian Islands, captured wild birds and put them in a darkened maze.
But first, they taped down some birds’ decorative feathers.
Infrared camera recordings showed that whiskered auklets bumped their heads nearly three times more often if their long head feathers were taped down.
Crested auklets suffered similarly with their crests taped down, but adding an artificial crest to the naturally unadorned least auklet, which also nests on the islands but in more open areas, didn’t help these birds avoid bumps.
Moreover, according to Sereviratne, “Birds with longer crests had greater difficulty in navigating inside the maze when their crests were taped down.”
“The evolutionary origin of the birds’ elaborate head feathers supports the idea that their first job was sensing, said Seneviratne.
He added that the auklets’ crests evolved from filoplumes, long hair- or thread-like feathers that lack normal feather structures and are attached to pressure-sensitive cells so they can detect touch.
In many birds, these feathers are hidden by larger contour or wing feathers, but in the auklets they stick out proudly where they can detect obstacles.
The research paper “is an interesting and probably a valid interpretation,” said ornithologist Alan Brush at the University of Connecticut.
He noted that some birds that catch insects on the wing have facial bristles thought to help them collect prey.