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:
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.
"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."
All photos on this post are from the free Wikipedia.