While watching the cam yesterday I watched one of the eagles look like it was going to cast a pellet. What is a pellet?
Eagles are carnivores. They don’t eat any plant material at all - no fruits or veggies for eagles! They get everything they need from the prey they consume. Typically, eagles eat the entire animal - the meat, bones, organs and even the fur or feathers. Eagles make very efficient use of their food, breaking down nearly everything to get the nutrients and energy they require.
An eagle’s stomach acid is very acidic with a pH close that of battery acid. With such strong stomach acids, they are actually able to digest even quite large bones. This is an important way the eagles get the calcium they need.
The only part of the prey that eagles can’t digest is the fur or feathers. About 12-18 hours after eating prey with fur or feathers an eagle will cough up, or cast, a pellet. A pellet is a compact bundle of indigestible material formed in the stomach/gizzard and covered with mucus. The fur or feathers in the pellet have little nutritional value to the eagle.
Owls are another raptor that cast pellets. However, owl pellets look a little different than an eagle pellet. Owls also typically consume whole prey like a mouse. But, an owl’s stomach acid is not quite as strong, so most of the bones are undigested along with the fur. So an owl pellet contains all the bones of the prey item. One cool thing to do is dissect the pellet and find out just what that owl’s been eating!
The eagle that I was watching did not cast a pellet, but was starting the contraction like movement that would bring a pellet up. Have you seen one of the eagles cast a pellet?