Bristle Feather Study
Bristle feathers are found on many species. Bristles are whisker-like feathers typically found around the mouth, eyelids and nares. Bristle feathers maybe unbranched or branched. The branched bristles can have minimum barbs at the base to more elaborate structures as found on nightjars. Some birds have both types of structures as shown in the various examples below. Bristles are sensitive to touch and vibrations. They assist in foraging and obstacle avoidance, protect from airborne particles, and sense airflow. Some sites state that bristles are used to funnel food. That was dispelled in an article about Willow Flycatcher bristles.1
I received an email from Dr. Menon asking if I had reviewed the bristles for the presence of afterfeathers. In review, there were several species with afterfeathers on bristles.
1Conover, Michael R. and Miller, Don E. (1980) Rictal Bristle Function in Willow Flycatcher. The Condor, Vol. 82, No. 4, pp. 469-471
As part of a feather study, I documented the bristle feathers of each species with some interesting results.
Two great articles on bristle feathers:
https://onlinelibrary.wiley.com/doi/full/10.1111/joa.13188
https://www.nature.com/articles/s41598-022-24781-7
Abert’s Towhee
ABTO, Melozone aberti
![Abert's Towhee bristles](https://hollandwest.com/wp-content/uploads/2023/05/Aberts-Towhee-bristles.jpg)
Abert’s Towhee bristles
bristle afterfeather
![Abert's Towhee ABTO bristle afterfeather](https://hollandwest.com/wp-content/uploads/2023/05/ABTO.jpg)
Abert’s Towhee ABTO bristle afterfeather
Acorn Woodpecker
ACWO, Melanerpes formicivorus
![Acorn Woodpecker bristle](https://hollandwest.com/wp-content/uploads/2023/05/Acorn-Woodpecker-bristle.jpg)
Acorn Woodpecker bristle
bristle afterfeather
![Acorn Woodpecker ACWO bristle afterfeather](https://hollandwest.com/wp-content/uploads/2023/05/ACWO.jpg)
Acorn Woodpecker ACWO bristle afterfeather
American Crow
AMCR, Corvus brachyrhynchos
![American Crow bristle](https://hollandwest.com/wp-content/uploads/2023/05/American-Crow-bristle-feather.jpg)
American Crow bristle
American Kestrel
AMKE, Falco sparverius
![American Kestrel bristle](https://hollandwest.com/wp-content/uploads/2023/05/American-Kestrel-bristle.jpg)
American Kestrel bristle
Barn Owl
BANO, Tyto alba
![Barn Owl bristle feathers](https://hollandwest.com/wp-content/uploads/2023/05/BANO.jpg)
Barn Owl bristle feathers
Clockwise from top left, nare, manible, below the eye, above the eye
![Barn Owl bristle feathers](https://hollandwest.com/wp-content/uploads/2023/05/2023082901048-BANO.jpg)
Barn Owl bristle feathers
Burrowing Owl
BUOW, Athene cunicularia
![Burrowing Owl bristle feathers](https://hollandwest.com/wp-content/uploads/2023/05/BANO-bristles.jpg)
Burrowing Owl bristle feathers
![Burrowing Owl bristle feathers](https://hollandwest.com/wp-content/uploads/2023/05/2023083101091-BUOW.jpg)
Burrowing Owl bristle feathers
Cactus Wren
CACW, Campylorhynchus brunneicapillus
What look to be bristle feathers below the bill are actually modified contour feathers.
![Cactus Wren bristle feather](https://hollandwest.com/wp-content/uploads/2023/05/CACW-bristle-feather.jpg)
Cactus Wren bristle feather
![Cactus Wren bristle feathers](https://hollandwest.com/wp-content/uploads/2023/05/2023121301382-CACW.jpg)
Cactus Wren bristle feathers
Chicken
CHIC, Gallus gallus
Despite many websites that specialize in chicken related information, chickens do not have bristle feathers.
![chicken not a bristle](https://hollandwest.com/wp-content/uploads/2023/05/chicken-not-a-bristles.jpg)
chicken not a bristle
Chukar
CHUK, Alectoris chukar
Chukars do not have bristle feathers
![Chukar not a bristle](https://hollandwest.com/wp-content/uploads/2023/05/Chukar-not-a-bristles.jpg)
Chukar not a bristle
Cooper’s Hawk
COHA, Accipiter cooperii
![Cooper's Hawk bristle](https://hollandwest.com/wp-content/uploads/2023/05/Coopers-Hawk-bristle.jpg)
Cooper’s Hawk bristle
Curve-billed Thrasher
CBTH, Toxostoma curvirostre
![Curve-billed Thrasher bristle](https://hollandwest.com/wp-content/uploads/2023/05/Curve-billed-Thrasher-bristle.jpg)
Curve-billed Thrasher bristle
Flammulated Owl
FLOW, Psiloscops flammeolus
![Flammulated Owl bristle](https://hollandwest.com/wp-content/uploads/2023/05/Flammulated-Owl-bristle.jpg)
Flammulated Owl bristle
Greater Roadrunner
GRRO, Geococcyx californianus
![Greater Roadrunner bristles](https://hollandwest.com/wp-content/uploads/2023/05/Greater-Roadrunner-bristles.jpg)
Greater Roadrunner bristles
A second review produced these results.
![GRRO bristles close-up](https://hollandwest.com/wp-content/uploads/2023/05/2023092701257-GRRO.jpg)
GRRO bristles close-up
From the bill area.
![GRRO bill bristles](https://hollandwest.com/wp-content/uploads/2023/05/2023092801264-bill-bristles.jpg)
GRRO bill bristles
From around the eye.
![GRRO eye bristles](https://hollandwest.com/wp-content/uploads/2023/05/2023092801266-eye-bristles.jpg)
GRRO eye bristles
Harris’s Hawk
HASH, Parabuteo unicinctus
![Harris's Hawk bristle](https://hollandwest.com/wp-content/uploads/2023/05/Harris-Hawk-bristle.jpg)
Harris’s Hawk bristle
bristle afterfeather
![Harris's Hawk HASH bristle afterfeather](https://hollandwest.com/wp-content/uploads/2023/05/HASH.jpg)
Harris’s Hawk HASH bristle afterfeather
House Finch
HOFI, Haemorhous mexicanus
![House Finch bristle](https://hollandwest.com/wp-content/uploads/2023/05/House-Finch-bristle.jpg)
House Finch bristle
Ostrich Bristle Feather
OSTR, Struthio camelus
Close-up of Ostrich bristle feathers. A close-up of the eye shows eyelash-like bristle feathers. Note the barbs.
Ostrich bristle feather
Red-tailed Hawk
RTHA, Buteo jamaicensis
![Red-tailed Hawk bristle](https://hollandwest.com/wp-content/uploads/2023/05/Red-tailed-Hawk-bristle.jpg)
Red-tailed Hawk bristle
bristle afterfeather
![Red-tailed Hawk RTHA bristle afterfeather](https://hollandwest.com/wp-content/uploads/2023/05/RTHA.jpg)
Red-tailed Hawk RTHA bristle afterfeather
Ring-necked Pheasant
RNEP, Phasianus colchicus
![Ring-necked Pheasant bristle](https://hollandwest.com/wp-content/uploads/2023/05/Ring-necked-Pheasant-bristle.jpg)
Ring-necked Pheasant bristle
A look at 300X magnification shows some type of growth reminiscent of a filoplume. The vane was not as delicate as a filoplume.
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