Montag, 3. Juni 2013

Bird pellets, part 1

Pellet of a tawny owl.
Pellets are like Kinder Surprise choco eggs: you never now what you get! Especially the pellets of owls are very interesting, because in there you can find bones of small mammals. I know a lot of things about bird pellets and that’s why I will write two entries about this subject. In this part I want to give you an understanding of pellets and how the birds cast them. Also what you should do if you want to bring a pellet at home. A bird’s puke was never more interesting than now! Please read more under the cut!

Which birds cast pellets?
If you think owls and bird of prey are the only birds which cast pellets you’re wrong. Storks, kingfishers, herons, crows, gulls etc. cast pellets, too.
As I mentioned before, the pellets of owls contain a lot of bones or chitin of bugs, because the stomach acid of owls isn’t that hard as the one by birds of prey. So you can check what the owl ate and (maybe) from what kind of owl the pellet was. Almost all owls eat small mammals like mice and shrews, but sometimes they eat small birds and insects, too. It depends of the kind of owl and of the food supply.
Pellets of birds of prey rarely include bones, they are more like fur balls.

Pellet of a common buzzard.
How does an owl create a pellet?
Birds don’t have teeth so they often need to swallow their food in one piece. Owls and birds of prey don’t have a crop, the food goes into a true stomach (Proventriculus) first. There the stomach acid and enzyme will do the groundwork and open the food up. Since the owls stomach acid isn’t that hard, there will be a lot of indigested food left.
After it’s done, the predigest food goes to the gizzard. That’s the “collecting tank” for the indigested parts, only the good stuff pass it and went down into the gut, where enzyme of the liver and pancreas digest the rest of it.
The hair and bones etc. will go back to the true stomach were they get formed to a ball, the pellet. The scratchy stuff like bones will get surrounded by hair, so the owl doesn’t get hurt while it vomits the pellet out. The pellet is covered with saliva for a better gliding as well. A freshly retched pellet is shiny, an older one is mat.
An owl needs about six or twelve hours for to create a pellet, so there are about two pellets per day.

Where can you find pellets?
If you know where buzzards sleep or if there are any places with a lot of gulls it’s easy to find pellets. But what about owl pellets? I wasn’t that lucky so far so I think it isn’t that easy to find owl pellets. Depending on the kind of owl you can find their pellets on borders of woods or in the wood itself. And you can find pellets of the barn owl by barns (obviously).
You have the best chance to find some pellets if you know where the owl sleeps or where an owl nest are.

Why you have to pay attention if you want to bring a pellet at home?
A pellet is very light and fragile so if they lay around for a longer time it will fall apart soon. Also some insects love to eat pellets or like to lay their eggs inside - that’s just eeewwwww!
It’s possible that some virus (hanta virus) call a pellet their home, too so you should not touch a pellet with your bare hands!
If you want to get rid of the insects and their maggots you should put your pellet into two plastic bags and put it in the icebox for about two weeks. Don’t forget to write the date and the find spot on it. But pay attention, the cold won’t kill viruses and spores! If you want to anatomize the pellet after freezing, put it in a bowl with 70% alcohol or spirit for about 10 minutes, then it’s ready.
Some people douse the pellet simply with boiled water. I don’t know if it’s sure enough, maybe I’m just a panic pants ;)
Another way to kill insects AND viruses is to heat the pellet up. Moisten the pellet with water and put it in a bowl, cover it with a plate and put it into the microwave. Use a towel between the bowl and plate to soak up the steam. Give it three minutes and full throttle, dude!
You can also bake the pellet for several hours by 150°C.

How to storage dry and disinfected pellets?
My owl pellets were in pressure lock plastic bags with a piece of cardboard for a better stabilisation in it. And I wrote the name of each owl on it as well.
For a better presentation you can also use acrylic boxes. Maybe it’s better to glue the pellet onto the bottom of the box, so it can’t get broken. The pellet also gets more solid if you spray some hairspray over it. And don’t forget to spray some insecticide over it (two words: museum beetle!).
Of course an empty metallic tea box would be fit as well.

I hope you enjoyed the first part of my pellet series. If you have some experience with pellets, too, I would be glad to read about it.
Next time I will write about anatomizing a pellet and how you can tell the different pellets apart. It will be posted very soon after this entry, just stay tuned!

3 Kommentare:

  1. Really good post ! I pulled apart nine different pellets I had collected but I haven't got round to identifying them or writing about them yet.

    1. Thank you very much, I'm glad you like it. Owl pellets are very interesting and it's always a joy to find them.

  2. Hello (Guten tag),

    I'm the director of french association. I've prepare exhibition of panels and games on animal marks. Could i use your photo of buzzard pellet for this? Wich author's name must i write on ?

    Thank you for your ansmwer