BIRDS CAUGHT AS THEY YANK OUT THE HAIR FROM LIVE ANIMALS TO BUILD THEIR NEST

Parents will do almost anything to ensure a roof over their children’s heads, and bird parents are no exception to this. Many birds go to huge lengths to build a suitable and stable home for their little chicks to come. 

We all have seen how birds will fly around with small twigs and leaves for their nest, but what else can this amazing creatures use of make use of to build their nest. An analysis of Youtube videos showed that many birds take the duty of building their nest to a new level by plucking hair off of living animals in order to fill their nests.

The inspiration for the new YouTube study came in 2020 after co-author Henry Pollock, a postdoctoral researcher in ornithology at the University of Illinois at Urbana-Champaign, and his colleagues were out in the public park surveying birds when they came across a tufted titmouse, which is a small, gray-and-blue bird with a pointed black head crest. 

At first they didn’t think much of it but the two biologists were soon shocked by what the bird was doing. Standing on a raccoon's back, the little bird started plucking hair from the animal. Pollock revealed that it was "At that moment, my curiosity was piqued”. 

Titmice are members of Parulidae, a bird family known for building nests that contain mammal fur. Pollock explained that at first Ornithologists had assumed that the fur found in their nest typically came from animal carcasses or shed hair. "There's a lot of evidence of birds using hair in their nests. Where that hair is sourced from has never really been investigated."

After trying to search for academic explanations for the shocking behaviour of the titmice, Pollock came up short and discovered that this interesting topic has been neglected by researchers for many years. One paper that was published in 1946 by a researcher named A. C. Bent, described seeing a titmouse pull hair from a red squirrel's tail. But the occurrence was reported more as a curiosity than as an example of a widespread behaviour. 

After realising that there were so little recorded observations in the scientific literature, Pollock turned to YouTube where he found dozens of videos of birds braving big animals to steal their hair, presumably for nest material which suggested that the behaviour was widespread.

Pollock and his colleagues wrote a formal scientific description of the hair-pulling behaviour in their recent paper, which they referred to as kleptotrichy, from the Greek roots "klepto-," meaning "to steal," and "trich-," meaning "hair." They cited previous anecdotal descriptions of avian hair pulling, and added dozens of YouTube videos showing birds pulling hair from dogs, cats, raccoons and sometimes even humans. 

Seeing that there is no scientific answer for as to why the birds steal hair as opposed to scavenging it, Pollock could only speculate and added "There's a clear fitness benefit to the behavior, or it wouldn't have evolved.” He also added that there are some bird which are known for using hair to keep their nests warm, but that doesn't explain why they would go to the effort to pluck the hair from live animals. Another hypothesis that is still untested is that bird use the fur from live animals to avoid predators or parasites. 

"There is a utility to bird-watching and popular media. It can give you a new perspective that you might not always get from the stuffy scientific literature."

The paper, "What the pluck? Theft of mammal hair by birds is an overlooked but common behavior with fitness implications," was published July 27 in the journal The Scientific Naturalist.