July 14 notes: questions & answers
The blog has become part of our daily routine to see how things are going and helps us draft the Journal notes! Bucky and Mark are away this week, so I will use the opportunity to briefly address some of the topics you have raised in the last week.
(1) Size differences: Females eagles are about 10 - 15% bigger than males from the same area. Eagles from northern latitudes are larger than those from southern areas. (Thus, a large female eagle from Florida might be about the same size or a bit smaller than a male eagle from Nova Scotia and much smaller than a female from northern regions.) When we handle an eagle, we measure the width of the lower leg and the depth of the beak as reliable distinctions between males and females! When eaglets fledge, they are essentially full grown although there may some of the larger flight feathers are still actively growing when they first take flight.
(2) Identifying Big & Little: When you see the fledglings one at a time, it's hard to judge size and identify them. BRI is controlling the camera zoom, and changes will affect the image size on your screen. Also, relative positions from the camera affect size perceptions. The nest is about 4 feet in diameter and the camera view usually captures lateral limbs about 5 feet closer and further away than the nest. Many have reported behavioral distinctions and quirks between Big & Little: good strategy! Perhaps next year we will band the eaglets (when about 6 weeks old) and use color bands with distinct codes to aid your viewing. You will be amazed that such an intrusion at the nest is tolerated, but careful timing is the key safeguard ... as it is in most of our management decisions to avoid disturbances to breeding eagles.
3) Little's fledging experience: I THINK Little probably went all the way to the ground on July 4. There are not that many limbs below what you see near the nest in the camera view and our savvy landowners can easily scan them There is no way Little could have climbed back up (although some raptors can in lesser trees) since the bottom 50 feet of this nest tree has no limbs to aid the ascent. Even with a forward flip start, it is likely that some wing flailing lessened the speed of his descent and effectively cushioned his fall.
4) Grounded fledglings: Most take short flights to higher limbs in adjacent trees to regain heights and return to the nest. This could take a day or more, especially during the foggy conditions recently prevalent near the eagle cam'. Some fledglings have more skill (or luck) with first flights, but smooth landing are a mystery that escapes most fledglings for a few days. The hops and lunges from the nest to surrounding limbs are good practice, and all flapping motions help build important flight muscles. Remember, Big & Little have been stationary in the nest for most of their lives so more exercise, gradually longer flights, and time are all important ingredients to their development on-the-wing.
5) Bruised leg? Little may have had a bruise of other soft tissue injury from his fall on July 4. It was not a broken leg. Such an injury would have prevented a return to the nest, clinching food, etc. One-footed perching is not that unusual, especially on slanting limbs as many are around the nest. Most viewers seem to notice steady improvements, concerns have lessened, and admiration for the fledglings' development is dominant in the blog. Enjoy!
6) Interventions: Unless a serious injury manifests, the fledglings are much better off with adult parents than being taken into captivity for veterinary attention or rehabilitation. The coming weeks are their ONE chance to learn survival skills while still living a guarded existence with Mom & Dad. Note the incredible restraint that the landowners demonstrated during the shaky fledging period: well done! We were all curious about the fate of the eagle cam' fledglings, but this development period is critical both in the short term and chances for future survival. Interventions for Little could have jeopardized Big in this crucial period and could not be justified unless absolutely necessary.
7) The next week: As long as the family group is together and disturbances are minimized, I doubt that inadequate food will be a factor at this stage. Little seems to occasionally get the edge in food squabbles. Which eaglet prevails at any given feeding might only reflect which one is hungrier. When both are content, indeed there is harmony at the nest. They will lay prone in the nest less and less as time progresses, and eventually time spent at the nest diminishes. I know you miss seeing the adults, but their absence from the nest encourages the fledglings' development. As noted before, one or both are usually watching carefully from a nearby. For example, I once watched an eaglet alone in a nest for 4 hours with no adult in sight, when an osprey circled twice overhead. The eaglet gave an alarm cry, and both adults were chasing away the intruder within 15 seconds ... but I had not seem them at all until that moment of need! The fledglings are usually inept at catching food so adult eagles will continue to make food drops at the nest or at other locations frequented by the fledglings.
-- Charlie Todd, Maine Dept. of Inland Fisheries and Wildlife