Yesterday morning I may have photographed a hummingbird casting tiny pellets. I’d never heard of such a thing in hummers.
Pellet casting in birds is more common than most folks think. Owls are well known for it but most raptors and many arthropod-eating songbirds and shorebirds also form and cast pellets as a means of discarding indigestible materials (insect exoskeletons for example) without them having to pass through the entire digestive tract. The indigestibles are simply formed into a compact pellet and expelled through the mouth. I’ve photographed a wide variety of bird species casting pellets over the years.
But I’d never heard of hummingbirds casting pellets. The diet of most hummers is primarily nectar but they also need protein which they get by eating a relatively small amount of tiny insects and spiders which of course have chitinous, indigestible exoskeletons. Due to the high water content of nectar, hummer waste is composed mostly of a clear, watery liquid but dark fragments of arthropod exoskeletons can often be seen in their watery ‘urine’.
I wondered if hummers are known to cast pellets orally instead of passing indigestibles through their digestive tract so I tried to research the subject but came up empty. Nowhere online can I find any reference to hummers casting pellets. Even Cornell’s exhaustive Birds of the World doesn’t mention it in the three hummingbird species I researched – they only mention “insect cuticle” passing out in their watery wastes.
So last night while I was reviewing photos taken yesterday morning I was more than a little surprised when I found photos that appear to show a hummingbird casting tiny pellets.
The following photos are presented in the order they were taken. Keep in mind that with my camera there’s only 1/10th of a second between photos in a burst.
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It was our old friend the feisty young Rufous Hummingbird who had just landed on his favorite amaranth perch in my garden. Soon after he landed he began to repeatedly stick his tongue out, a very common practice among hummingbirds. Common or not I like to photograph their unique tongues so I fired off a quick burst, expecting to capture nothing more than his tongue action.
I got more than I bargained for.
After sticking his tongue out several times he violently shook his head, as if there was something stuck to his head that he was trying to get rid of. I’ve seen this kind of head shaking many times from birds trying to expel pellets from their mouths.
A closer look at the same photo gives us a better look at what appears to be a dark mass of some kind at the tip of his lower mandible. Maybe it is and maybe it isn’t.
Then he opened and closed his bill.
As he stuck out his tongue again a tiny dark mass suddenly appeared in his bill near his mouth.
The process of sticking his tongue out even further appeared to draw the dark mass to the tip of his bill.
Once it was at the tip of his bill he clamped down on it to hold it in place which allowed him to retract his tongue back into a more normal position.
But then he stuck his tongue out again with the dark mass still near the tip of his bill.
1/10th of a second later the mass was gone and his bill was closed.
I never did capture any of the dark bits being dropped or flying through the air but that doesn’t surprise me much. Hummers are so incredibly quick that 1/10th of a second is almost an eternity to them.
So what do you think? Was this a pellet (or pellets) being expelled? I’m not claiming for certain that it was but I can think of no other logical explanation.
Ron
Note:
Within minutes of me publishing this post my good friend Jim DeWitt found this reference to hummingbirds forming pellets in an online technical paper. It mentions pellets being formed internally but it doesn’t say they’re expelled orally. Jim is a retired attorney so he’s had lots of practice doing research but I’m still impressed. I sure couldn’t find anything.
Sorry about the formatting problems.
“Formation of pellets. I have twice found pellets (consisting of
chitin) in the stomachs of hummingbirds. Fine pieces of chitin are
ground by ordinary stomach action and excreted through the intestine,
as analysis of feces shows. But pieces of chitin too large and hard for
digestion are apparently regurgitated in the form of pellets. I found
both pellets in March, when the drought was most severe and the
species I encountered were feeding entirely on animal prey. A specimen
of the Red-billed Azure-crown had in its stomach a round pellet, 4 mm.
in diameter, made up entirely of coarse pieces of chitin pressed tightly
together. The other pellet, found in a specimen of the Pine Star-throat,
was the same size, but rather more oval in shape. Wetmore ( 1916: 73)
says that Green Mangos (Anthracothorax Gridis) “undoubtedly regurgitatewaste matter, in the form of pellets, from which the nutrimenthas been digested. Several of these, 2 millimeters long by 1 wide, ready
to be expelled, were found on opening the stomachs, and in each case
consisted of a firmly compressed pellet containing chitinous fragments
of insects and spiders.”
Fantastic! Once again you are sharing with us the frontiers of knowledge. There seems to be no doubt about what you have documented.
Fascinating! To butcher the old “walks like a duck” analogy, if it casts like a pellet…
Hope you’re staying safe with the fires around you and are enjoying your tomatoes. I’d love to see one of your BLTs show up on the blog. 😉
Thanks, Marty. It’s been a great tomato year. They aren’t huge but they sure are tasty and I have oodles of them. I’ve been giving them away to relatives, my neighbor and my ex-wife.
We’re so addicted to BLT’s with garden tomatoes we have them for dinner about every six days this time of year. We very rarely make it a full week without them.
Well Marty, I hope you’re happy. We had BLT’s for dinner five days ago but within minutes of reading your comment I was drooling on my keyboard to have them again. Tonight!
But then I realized I didn’t have enough of our favorite bacon (Daily’s Honey Cured – Thick Cut) so I just got back from my favorite local meat market and this time I bought two 1.5 lb. packages of that wonderful stuff. I’ll freeze one of them so I have it on hand for next time we get the urge – which I’m sure won’t be long.
Pics or it didn’t happen. 😉
Pic sent via email.
Great photos, Ron! I’m trying to think of who is doing hummingbird research that might love to see these to form a research project?!
And, actually, Dan just reminded me: we sat in on a video chat with two hummingbird researchers last week that are connected with Cornell Lab of Ornithlogy. One of them is a woman based, right now, here in Oregon, up in Newburg, OR, Anusha Shankar. Here is a link to the online lecture we tuned in to hear…
https://academy.allaboutbirds.org/live-event/how-high-energy-hummingbirds-survive-a-qa-with-the-experts/
The other fellow is up in Canada… Anusha is not exactly connected with the college where she is doing their research; she’s listed as a researcher at Cornell…
Here is a link to her page: https://anushashankar.weebly.com/research.html
Wonder if she might know someone who might want to know of your photo?
Thank you for the links, Barbara. I’ll check them out.
Wow. Another gorgeous and informative entry. Thanks so much Ron. I learn so much about birds which I feast my eyes on your beautiful photographs.
Thanks very much, Sheila.
I’ve watched many species of bird bring up pellets, which, in raptors, are called castings. Why “castings”? because they are a cast of the inside of the birds muscular stomach, sometimes called gizzard. Bird’s typically have 2 stomachs; one glandular in which the food is combined with digestive fluids. The other, muscular, in which the food and digestive enzymes are mixed and digested, sometimes with the aid of little stones. Then the almost fluid initial digestant moves into the small intestine for further digestion. The large undigested material remains in the muscular stomach where it is squeezed of the nutrient fluid forming a cast of the inside of the stomach. When that fills the stomach it is “cast’ up as a cast or a pellet; words more acceptable to humans than vomited up oral excrement.
Fabulous documentary photos!!!!
Thanks for the info, Elizabeth. Yes, terminology matters doesn’t it.
I LOVE your behavioural series and this is no exception. It makes a heap of sense that they would cast pellets and that it is certainly the story that this series of photos tells.
Thank you.
Thanks very much, EC.
Wow, incredible what you see through your lens! This is notable documentation, Ron. Yay you!
Thanks very much, Susan.
Now *that* is really something! I mean, hummers are so fast at expelling their waste via the “normal” route you have to watch closely to see it … this is something we’d only get a look at with Ron Dudley’s super-sharp focus.
The other thing I noticed is the nictitating membrane in the second and third shots — somehow I never thought about hummingbirds having those! Fabulous post with amazing insight and info, Ron.
Thank you, Chris.
I took another interesting short sequence yesterday that I may post sometime in the future. In the first photo the hummer is facing me on his perch but with his bill pointed straight up because he was looking at another hummer in flight directly above him.
In the next shot in the burst the hummer is out of frame because he took off straight up after the other bird. BUT instead of the hummer in the frame I had a big load of hummer pee falling toward the ground.
Maybe he scared the piss out of the bird he was chasing… 🙂
I’m convinced by the photos. In the reference it says pellets were found in the stomach. There is no reason to form a pellet in the stomach unless you are going to regurgitate it. Passing a pellet down the long way may not even be possible. Intestinal contents is liquid, all, or almost all the way down. Passing a pellet all the way down seems very unlikely.
Time for somebody with a super high quality video camera to get on this topic for final proof. Or you could just sit in your back yard for a few more days burning through data cards!
Great stuff Ron. Thanks
“Or you could just sit in your back yard for a few more days burning through data cards!”
Porcupine, thanks to the wildfire smoke that’s exactly what I’ve been doing for the last three days. It was nice to get back up into the mountains this morning.
Very amazing indeed!
Thanks, April. I enjoyed seeing your photos of hummingbird “boatmen”. I’ve seen and photographed them coming out of the bird and in the air but haven’t seen them isolated like that.
Ornithologists and serious bird photographers everywhere are looking at your photos and thinking “Well, I’ll be dammed. It makes perfect sense, but this guy actually documented it.”
By the way, you didn’t happen to hear it go “gaaak”?😜
Nope, I didn’t hear any “gaaak”, Lyle. Unless it was from me… 🙂
Fascinating! Appears you have captured new behavioral data for hummers! Congrats!!
Thank you, Kathleen.
I just did a little more searching and found a reference to pellet-casting in the Green Mango. From Birds of the World:
“Indigestible chitinous food remains are regurgitated as pellets.“
I searched information of many species of hummingbirds but there are just too many to look at them all. The reference from your friend gave me the lead. The Green Mango is a hummingbird found in portions of northeast South America.
Sounds like you had more patience in your research than I did, Dan. I researched only 3 species (Rufous, Broad-tailed and Black-chinned) and when I didn’t find confirmation of pellet casting I just gave up.
Incredible documentation. I’ve never seen direct evidence of pellet-casting in hummingbirds but it makes perfect sense. Everything happens so quickly in a hummingbirds world that I’m not surprised that this has been missed before. Some insects and spiders have very heavy exoskeletons and if several of these had been eaten, it makes sense that a pellet would be formed rather than have that mass pass through the digestive tract. Head shaking and flicking the tongue in and out are common behaviors in hummingbirds. A pellet would be tiny and very easily missed during these behaviors. I wonder how many times may we have seen this and never known it. With even small songbirds pellet-casting is slower and more obvious. Hummingbirds are amazing in so many ways and you’ve given us another bit of info to add to that wonder. Many thanks.
Dan, I was really hoping you’d chime in on this so thanks very much for doing so. Your comment makes me more confident about my presumptions regarding what I documented.
Fascinating. And the close photos are spectacular.
Last summer, I saw a Robin casting. I looked for the pellet after he’d flown away (it was a male, I’m not being sexist), and didn’t find it, but he went through the head shaking and something careened off into the weeds.
Thanks, Sallie. Often when robins regurgitate ‘stuff’ it’s whole fruit seeds or pits rather than compacted bits of many things. I wonder if that still qualifies as a pellet – my guess is no, but it’s still the same process.
I imagine you’d much rather be venturing away from your yard to take photos, but you sure made the best of a bad situation with this series. I love learning from your blog as much as I enjoy the great photographs.
“I imagine you’d much rather be venturing away from your yard to take photos”
Linda, I smiled when your comment came in because I read it on my phone while I was up in the mountains photographing birds! The smoke finally cleared out enough for me to do it.
Wow! Absolutely fascinating behaviour study. I should think it would at least provide enough fodder for some serious investigation in the right hands. Well done indeed, both the photos, and the questions you raised about your observations.
Much appreciated, Pat.
Fascinating series, Ron, with beautiful photos. Thanks for sharing.
Thank you, Diane.
Incredible photography. Without photography like this you would never ever see a hummingbird expelling anything. Everything they do is at super speed plus. Your Rufous friend is definitely expelling something. Jim DeWitt’s research certainly confirms that they do have pellets from time to time. Very interesting and educational post.
Thanks, Everett. Jim is often helpful on my posts but he makes his comments on Facebook so my regular blog followers don’t see them.
Very cool sequence. With all of my hummingbird images, I’ve never seen that. Pretty neat.
Keith, given all the hummer photos you’ve taken over the years that’s saying something. Thanks for that feedback.
Interesting! ALWAYS something to learn….. 🙂 Wonderful photos of the hummer and their VERY long tongues as well as capturing the pellet even if you didn’t actually see it dropping. Jim certainly a valuable resource for your! 😉
Judy, I looked hard for a falling or flying pellet in the air in several of my photos but nary a thing. That doesn’t surprise me though – hummers are speed demons.
Amazing information and photos to go with it.
Thank you, Cindy.
It’s definitely something. I am continually amazed by what you find in your shots.
” I am continually amazed by what you find in your shots.”
Sometimes I am too, Arwen. This was one of them.
I had no idea! This is unquestionably one of the most interesting (to me) bits of information you’ve shared. I continue to learn from you. Thank yoiu.
Thanks very much, Nancy.
Hi Ron, Great documentation of suspect “pellet” expulsion that, in my opinion, would grade with 99.9 percent certain, as your photo #5041 and #5042 does clearly show a foreign object in your photo burst. I’ve been convinced they do expel pellets! Don
Thanks, Donald. It certainly seems logical that they would expel pellets.