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
bristle afterfeather
Abert’s Towhee ABTO bristle afterfeather
Acorn Woodpecker
ACWO, Melanerpes formicivorus
Acorn Woodpecker bristle
bristle afterfeather
Acorn Woodpecker ACWO bristle afterfeather
American Crow
AMCR, Corvus brachyrhynchos
American Crow bristle
American Kestrel
AMKE, Falco sparverius
American Kestrel bristle
Barn Owl
BANO, Tyto alba
Barn Owl bristle feathers
Clockwise from top left, nare, manible, below the eye, above the eye
Barn Owl bristle feathers
Burrowing Owl
BUOW, Athene cunicularia
Burrowing Owl bristle feathers
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
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
Chukar
CHUK, Alectoris chukar
Chukars do not have bristle feathers
Chukar not a bristle
Cooper’s Hawk
COHA, Accipiter cooperii
Cooper’s Hawk bristle
Curve-billed Thrasher
CBTH, Toxostoma curvirostre
Curve-billed Thrasher bristle
Flammulated Owl
FLOW, Psiloscops flammeolus
Flammulated Owl bristle
Greater Roadrunner
GRRO, Geococcyx californianus
Greater Roadrunner bristles
A second review produced these results.
GRRO bristles close-up
From the bill area.
GRRO bill bristles
From around the eye.
GRRO eye bristles
Harris’s Hawk
HASH, Parabuteo unicinctus
Harris’s Hawk bristle
bristle afterfeather
Harris’s Hawk HASH bristle afterfeather
House Finch
HOFI, Haemorhous mexicanus
House Finch bristle
Ostrich Bristle Feather
OSTR, Struthio camelus
Ostrich
Close-up of Ostrich bristle feathers. A close-up of the eye shows eyelash-like bristle feathers. Note the barbs.
ostrich close-up
Ostrich bristle feather
Ostrich bristle feather
Red-tailed Hawk
RTHA, Buteo jamaicensis
Red-tailed Hawk bristle
bristle afterfeather
Red-tailed Hawk RTHA bristle afterfeather
Ring-necked Pheasant
RNEP, Phasianus colchicus
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.
300X bristle feather tip
White-breasted Nuthatch
WBNU , Sitta carolinensis
White-breasted Nuthatch WBNU bristle feather
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