Casting A Pellet

(Red-tailed hawk casts a pellet, photos by Chad+Chris Saladin)

8 January 2019

Why does this red-tailed hawk throw up a long gray lump? Is he sick? Not at all. He’s casting a pellet.

Birds’ digestive systems are very different from ours, beginning with their beaks. Since birds don’t have teeth they swallow most of their food whole. The rest of their digestive system is geared to deal with this.

Birds have little saliva and few taste buds compared with mammals, which chew and physically process food as the first step and then subject it to chemical processing as the second step. Birds reverse this sequence. They start chemical digestion in the proventriculus [then the food] undergoes physical processing in the gizzard.

Ornithology, 3rd Edition by Frank B. Gill, page 164

We chew with our teeth and spit out the bones. Birds chew with their gizzards which collect the bones, fur, and other indigestible bits into a lump. The bird spits out the lump when it’s a convenient size.

Owls, eagles, hawks and falcons cast pellets but so do many other birds “including grebes, herons, cormorants, gulls, terns, kingfishers, crows, jays, dippers, shrikes, swallows, and most shorebirds.” (quote from Wikipedia)

Scientists examine pellets to find out what the bird ate. One of the long-eared owl pellets below was dissected to reveal the rodent bones inside.

Pellets cast by a long-eared owl, dissected to show rodent bones (photo from Wikimedia Commons)

For whatever reason, it’s rare to see a bird casting a pellet so consider yourself lucky if you witness it, as Chad+Chris Saladin did in the photos above.

A NOTE ABOUT HANDLING OWL PELLETS from Wikipedia: Some rodent viruses and bacteria can survive the owls’ digestive system so wear gloves and sterilize the pellets in a microwave oven before handling. A 2005 study found outbreaks of salmonellosis at elementary schools associated with dissection of owl pellets: Smith KE, Anderson F, Medus C, Leano F, Adams J, 2005. Vector-Borne and Zoonotic Diseases,5, 133–136.

(red-tailed hawk photos by Chad+Chris Saladin; pellet photo from Wikimedia Commons; click on the captions to see the originals)

7 thoughts on “Casting A Pellet

  1. On Midwest Peregrine Soc (Facebook) the Providence Raptor page posted a photo of a Peregrine pellet which contained the band from a racing pigeon! Just saw that again yesterday.

  2. Fascinating stuff as usual—thanks Kate! Once on a bird outing/walk at Black Lick natural preserve (no facilities, strictly water, woods and fields) a group of us (Todd Bird Club outing) found a pellet where there was a Great Horned Owl and one gentleman dissected it for us all–interesting stuff of course…besides a few partial feathers, and tiny bones there were a few partial shells)

  3. Thanks Kate for clarifying an encounter from a few years back. Guess I witnessed a Kingfisher throw up a pellet once . I wasn’t aware that they did this and thought it was sick.

  4. Wow!!! These pics are just amazing. We found a pellet today and I dissected it with my kids. Not sure what it was from but we have seen a huge red tailed hawk in our backyard. So, I searched for red tailed hawk pellets and found your post. So cool!

  5. I would like permission to use the photo of the red-tailed hawk casting the pellet for a power point presentation I am putting together. It is for fire investigation and related to a case where castings of fish scales were discovered at the base of a power pole where a fire had started. I would like to use the photo to illustrate to the audience what a casting is.

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