New bird – female or juvenile American Redstart


It is hard to identify a female or juvenile warbler that has very different plumage from a male of the same species by scrolling through a list of warbler photographs. I finally had my eureka moment when I Googled “yellow and black tail feathers”.


This feathered creature was actively hopping from branch to branch, in a pretty Cutleaf Weeping Birch, probably startling some insect snacks by spreading its tail and quickly flashing the yellow feathers. Where the female and juvenile birds have grey and yellow feathers, the breeding males have pitch black and bright orange feathers.


Oo, it has whiskers. It turns out they are specialized feathers called rictal bristles. They are common in insectivorous birds. They help protect the bird’s eyes from objects hitting them when the bird is in flight. The experiment did not sound fun for the birds.

“Particles released in front of the bird’s open mouth and blown back towards its head struck an eye more frequently after the rictal bristles had been removed.” (M. Conover and D. Miller, 1980)


Setophaga ruticilla means moth-eating redtail (based on breeding male tail colour).




  1. Nice photos of this juvie or female! My son had told me about rictal bristles before, but I’d forgotten so thanks for reminding me. 🙂 And, yeah, that sounds like an awful experiment for the birds…

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    • Thanks Teresa :-).

      Well, I have to admit I only read the journal article’s abstract. So I thought… maybe the statement needs more context? Do bristles grow back? Did the bristle-less birds wear eye protection as bits of stuff were flying at their face? Did they suffer much? So I went to the results section and read that they had adhesive discs on their eyes. Hmm, how did the scientists put those on? So I backtracked. Turns out the birds with adhesive discs on their eyes were preserved… I guess that means stuffed. So the birds with particles flying at their faces were stuffed with their mouths open and a rod up their butts. Context!

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    • 🙂 I’m glad you are enjoying the new birds too. They’re so ephemeral!

      I decided to look up more details about the rictal bristle experiment since I got the statement from the abstract and assumed the birds suffered. On second thought, it seemed possible that the birds wore some eye protection. I turns out the birds in the experiment did have something over their eyes… but the birds were also dead. So, not super-nice, but nicer.


        • Advances in medical knowledge are very interesting and beneficial in many ways but there is a lot of animal cruelty involved in making these discoveries. Some improvements have been made, like some countries banning research on great apes and some cosmetic companies not testing on animals. But I think there is still a lot of room for improvement. I’m glad you are too kind to perform cruel experiments on animals.

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