I noticed that my male canary was wiping his bill frequently in the presence of a female I introduced him to, and it got me wondering….

QUESTION:  Why do birds wipe their bills?

ANSWER: Birds probably wipe their bills for a variety of reasons.  But let’s start with what counts as bill wiping.  Here’s a technical description:

“rapid withdrawal of the side of the beak from base to tip closely adjacent to a foreign surface such as a branch or the ground.” (Clark, 1979)

Bill-wiping - starling
A starling wiping its bill on a branch. Illustration by R. Gary Graham from Colorado Gardener magazine, “Starlings, Fascinating Garden Variety Dinosaurs”

Birds often wipe both sides of their beaks, alternating.  The number of wipes per session varies – a Double-barred finch was seen doing it 90 times in a few minutes (Morris 1957b).  The beak may be open or closed, and may or may not actually touch another object.

Since bill-wiping uses energy, it probably serves some kind of purpose.  It’s different from preening (where the bird uses its beak to fluff/arrange/clean/groom its feathers.)  Here are some possible drivers:

  • Hygiene:  A bird may wipe its bill to clean it after eating something messy, like suet, a juicy berry, or a sticky insect.  You might see them do this right after eating, bathing, drinking, or manipulating something in their bill.
  • Yuckiness: A bird may wipe it’s bill after coming into contact with something distasteful.
  • Displacement:  Maybe it’s a form of fidgeting in response to anxiety, frustration or feeling conflicted. It could be an agonistic (combative) behavior in response to a sense of conflict, like another bird or person coming into their “space.”
  • Power Move: A dominant bird may bill-wipe in the presence of a subordinate bird, as a sign of aggression, or in defense of its territory.  It’s a form of communication.
  • Sexual: Bill-wiping is often seen during courtship. A male may bill-wipe in the presence of a female.
  • Prelude to singing: Some birds might bill-wipe right before breaking out into song
  • Honing: Some birds like parrots will scrape their beaks on rough/abrasive surfaces like bark, to shape or file their bills. Bird beaks have a fleshy covering over the bone that is made of ever-growing keratin, like human fingernails, and wiping it may wear it down.
  • Chemical defense/attractant?: There is speculation that White-breasted nuthatches may do a sweeping bill-wipe to somehow deter predators from their nest area. Red-breasted nuthatches have been observed wiping pine sap along the entrance to a nest cavity – it’s stickiness may fend off invaders.  If a bird first wipes it’s bill on an oil gland (used to maintain and waterproof feathers) and then wipes it on an object, perhaps the intent is to leave a scent behind.


  • Avian Bill-Wiping, George A Clark, Jr,  The Wilson Bulletin, September 1989, Vol.82,no.3, pp 279-288.
  • Beaks and Bills,
  • Here’s Why Birds Rub Their Beaks on Stuff, Andy McGlashen, Audubon Magazine, May 1, 2019.
  • The Function of Bill-Wiping, Cuthill, Innes et al, Animal Behavior, Vol.43, Issue 1, January 1992, pp 103-115

More Information:

If you ask me “why,” I will either tell you what I think or tell you a lie – we usually can’t answer why.
– Keanna Leonard, Rowe Sanctuary, Kearney, NE


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