18 September 2025

When I visited Bird Lab’s Hays Woods banding site on Tuesday, I was excited to release an American redstart after she was banded, weighed and measured. Before I let her go I took a good look at her face and was surprised to see she had rictal bristles around her beak. On cats we’d call them “whiskers.”

Rictal bristles are stiff, modified bristle feathers that grow at the base of the birds beak — at the gape, or the nares (nostrils), the lores, or beneath the beak. They may or may not have barbs. They are not like other feathers.

Years ago I’d heard that rictal bristles were used to help capture flying-insect food but experiments have shown that is not the case.

Studies [published in SORA] have been done where the bristles of [willow] flycatcher were removed or were taped down. Neither of those actions adversely affected the birds’ ability to capture prey, indicating that the rictal bristles do not aid in prey capture. In those studies the flycatchers that had their rictal bristles taped down or removed had more debris from their insect prey land on their eyes.

— Mia McPherson: Willow Flycatcher Up Close – What Are Rictal Bristles?

Now that the food capture theory has been thrown out, new studies are looking into the evolutionary origin of avian facial bristles — how many birds have them? Other studies are trying to parse out the feathers’ purpose. Some bristles may protect the eyes or nose. Some may be tactile, just like cats’ whiskers. Some are a mystery.

And that’s where redstarts come in; their bristles made me wonder. Here are better looks at their faces.

Why do American redstarts have rictal bristles? More study needed.