Sunday, September 21, 2008

Bird Vomit

Synchronicities abound; I love it when that happens.

I have been reading a library book “Birds: Their Life, Their Ways, Their World”, Dr. C. Perrins (Switzerland). On page 187 of the book, in a page regarding Petrels, is a drawing of a bird spewing at a fox. At first I thought the lines were the ‘sound waves’ often drawn to show the bird might be squawking, but the description was: “A Fulmar Fulmarus glacialis deters a predator by projecting musky stomach oil.”

The synchronicity came when reading I and the Bird #84 regarding Bird Blogs. While checking out blogs I'd not seen before, I found the Bird Ecology Study Group; specifically the piece mentioned: Black-naped Tern's Defense Vomiting! Too fun!

However, there is something I question; don't parent birds hold food in their crops (or gullets?) and regurgitate that to feed chicks? I was not of the impression they actually vomited stomach contents into their youngsters. While several sites casually us the word 'stomach' this one says 'crop', which makes more sense to me.

From the article from The Wild Classroom on Feeding Adaptations: "Crops are part of the esophagus and are used as storage areas for food. A number of birds have them. Birds consume food, store it in the crop and then regurgitate it to their offspring. Digestive juices in the saliva break down food in the crop." The article then goes on to discuss 'The Stomach". And...I'm betting the Petrels, and apparently Terns, spew actual stomach contents; musky oil doesn't sound like baby food.

In this article: Muttonbirder selectivity of sooty shearwater chicks harvested in New Zealand ( Hunter, Moller and Kitson) is a discussion regarding how hunters make chicks 'spew' stomach oil by palpating the chick...so that later their feathers are not harmed later. This seems to me evidence even chicks spew when threatened. (see Pg. 3)

From this article regarding Fulmars:

"The vomit attack can be lethal for predatory birds, because the oily substance coats their feathers and makes flying difficult. Researchers have found the bodies of 10 different kinds of birds covered in the oily mess. Other fulmars seem to be the only birds able to clean the oil from themselves.

The birds can aim accurately up to two or three meters, Mallory said, speaking from his experience of being a target."

Do you, gentle readers, know about the vomiting defense-behavior in birds and if it is different than baby-food? Please leave a comment if you do...I'm very curious.

All photos on this post are from the free Wikipedia.

8 comments:

lkw said...

Oh, my - I wish I knew something more about this (way beyond my knowledge base). You've done a great job ferreting out information, it seems to me.... VERY interesting.

Beverly said...

LOL Well, thanks. It all started with the 30-year old book and then the Blog I happened to read. Past that...I'm a fan of the phrase "Google is your friend!"

It's too bad I never stayed in college; I really like research.

Eft said...

I have wondered this too and have not read anything definitive. What got me started on it were the persistent pink cheek stains on wandering albatross (presumably from allo-preening mates). Is that the same substance they feed chick (ie: viscous oil of digested foods) & is that the same stuff the chick vomits for defense? I think I read something about it in
"The Behaviour, Population Ecology and Physiology of the Petrels", by John Warham tho also think it's an open question. Very nice blogging -- cheers.

nina said...

Are those pretty little Gray Jays?
We saw some for the first time when traveling west this summer.A nice change from what we have here.

Bird vomit.
Hmm.

Beverly said...

Hiya Nina! Awwwwwwww…I was hoping you had something to add on this topic. I’m beginning to feel the stuff they spew for defense is the same that they feed their young. I’ve heard it called “…oily projectile vomiting”, but I’ve also read “…the oily-mix of seafood is full of protein for baby birds.” I’ve also read some gulls will go eat the stuff that misses the mark and hits the rocks; opportunists that they are.

Yes, Gray Jays; I’d agree with Sibley who mentions that with that tiny beak, they look like overgrown Chickadees. They are quite beautiful…but at nearly a foot long, are a good sized bird; the same size as a Steller’s jay.

Thanks for visiting!

John Carlson said...

Bev,
I know that we treated the Giant Petrels in Antarctica with great respect because they could projective vomit quite far. We called it "gack", as in "ooh, did you get gacked?"
The smell and stain would never come out of anything that got gacked. As to it's origin, I was always under the impression that it was stomach contents, but now I am not so sure. I will have to do some research and get back to you.

Beverly said...

John,

Thank you SO MUCH for the info you did leave. I’ve read, too, that the projective is something like 6-7 feet. And I’ve read its some special oil…for digestion…which suggests it comes from the stomach; and I’ve read it’s oily stomach contents.

I’m just trying to figure out if this ‘toxic mixture’ is, in fact, the same stuff, from the same place, that they feed chicks. In some ways that makes sense, in other ways…not at all.

Odd, isn’t it…that the birds who do this are apparently not phased by the vomit themselves, nor does it damage their feathers; they’re able to clean it up without problems, while other birds’ contaminated feathers (or jackets & backpacks) are ruined…apparently. Wild, huh?

I do hope you are able to find the answer…I figured the scientist in you would have access to such data! Thanks for playing…

Vickie said...

Interesting questions on a subject I know nothing about. Also enjoyed your native gardening post.