March 18, 2007
Eaglet Behavior
Before we talk about our two growing eaglets (17 days old and 15 days old), I wanted to share a link with those who missed our Eagle Festival a week ago. Paula -- one of our cam watchers -- has posted her photos from the Festival, so be sure to check them out if you'd like to see the Refuge and some of the fun activities we offered, such as the birds of prey we had on display, as well as our resident eagles flying around the Refuge. (Note: the captive birds of prey you see in the photos are formerly injured animals that are used for educational purposes since they cannot be returned to the wild). Much thanks to Paula for sharing her shots.
Second, be sure to read this wonderful cover article about Blackwater Refuge that is in the current issue of Chesapeake Life magazine. I think the article offers a good overview of the Refuge and what makes it so special to so many people.
Finally, I wanted to share an article on a golden eagle that was recently rescued in West Virginia and will soon be tracked upon release. Golden eagles are slightly smaller than bald eagles, but they are very impressive raptors that are much less common on the East Coast of the U.S. The article talks about the eagle's injury and illustrates the terrible danger of using steel animal traps, as they are a cruel form of trapping that can accidentally snare the wrong animal. Also note that if you follow the article link to the National Aviary website you can also learn more about the researchers' program to track golden eagles with a satellite.
Eaglet Behavior
We've been having some odd weather on the East Coast lately -- so odd that in less than a week we went from balmy days in the low 70's to frigid days with near-zero wind chill temperatures accompanied by rain and ice. The eagle family has been plodding along, trying to adjust to the unpredictable conditions, and they seem to be doing well.
Around the middle of the week it was warm, and we saw chick behavior that told us the eaglets were feeling the heat. A good example of this was when one chick started lying under mom, who provided shade with her body, while one chick tried sticking out its leg to help cool itself off. We'll see more of these behaviors as spring and summer bring hotter temperatures.
Something worth mentioning is the fact that heat is often a bigger threat to eaglets than cold, and that is why we see our raptor parents (both eagles and ospreys) using their bodies and wings to provide shade to raptor chicks during the warmer months.
But here at Blackwater Refuge, heat wasn't a problem at the end of this past week -- the problem was the sudden arrival of heavy, cold rain. Our mother eagle was like a rock as she stayed over the chicks for long periods to keep the eaglets warm and dry. Several cam watchers noticed that the mother didn't even make use of a fish that the father brought in for the family.
And that brings us to the topic of crops. During bad weather, our eaglets can wait to be fed since they possess crops. A crop is an organ located near the base of the bird's neck, and it stores food for later consumption. Our chicks are small, so it's hard to see their crops right now, but here are a pair of photos from our first Eagle Cam season where you can see our youngest eaglet's crop growing in size as he gets fed (he's the eaglet near the top of the image).
For the parents, the advantage of a crop is that it means the chicks don't have to be fed as often, since the young have food stored in their crop pouches. Adult eagles and most other birds have crops too, but they're often harder to see under all the feathers. It's been reported that an eagle with a full crop can usually survive at least five to seven days without eating.
While most birds have crops, owls in fact do not. They swallow their food whole and all of the prey goes into their stomach. Also, the stomach of an owl does not have the strong digestive juices that an eagle or osprey has, so the pellets that an owl regurgitates (pellets containing indigestible food) are usually filled with the full skeletons of the animals they ate. Often schoolchildren will dissect an owl pellet to learn more about what owls eat. You can dissect an eagle or osprey pellet, but they are smaller and contain less identifiable animal parts. If you're interested in learning more about owls and owl pellets, be sure to visit The Owl Pages website.
Another behavior that we saw this past week was the eagle parents covering the chicks with grass -- a common behavior used to provide protection from the elements or sometimes even protection from predators when the parents leave the nest for a bit. One of our chicks was covered so much that several cam watchers thought it had disappeared from the nest. :-)
One other concern for cam watchers was the way in which the chicks were getting close to the nest edge now that they are becoming more mobile.
It is somewhat rare for eaglets to fall out of the nest at this age, although as they get older they can get blown out in storms or get blown out when they begin holding out their wings to practice their flapping. While the threat is there that the eaglets could accidentally fall, that doesn't mean the parents are unconcerned or unaware. In fact, they too watch the chicks and their proximity to the edge. In our first Eagle Cam season we saw an excellent example of how carefully the parents were watching the chicks as one night an adventurous eaglet kept getting closer and closer to the edge -- looking as if it was determined to go all the way over. The parent was close by, patiently watching the chick, and then the parent finally came over and herded it back to the center of the nest. What was even more remarkable about this scene was that eagles do not have much better night vision than humans, yet the parent was very aware of how close the eaglet was to danger even in the darkness.
Final Note:
When I was at the Eagle Festival last week, I captured some more video from our live Eagle Cam at the Visitor Center. I haven't had a chance to edit it yet, but I will try to put together a couple video clips for our next web log. The chicks will look a little younger in the video segments than they do now, but I think you will enjoy seeing some new behaviors from our eagle family -- like how the chicks interact with each other and how they slice over the nest edge to keep the nest tidy.
Until next time,
Lisa - webmaster
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