palmer@whistler.sfu.ca (Leigh Hunt Palmer) (02/27/91)
In mid December I observed two bald eagles (one of them obviously immature, but looking somehow larger than the adult) perched in separate trees next to Deer Lake here in Burnaby, B. C. They came to the lake at about the same time, and I take them to be parent and offspring nesting on the adjacent lake. Both sat on their perches, changing trees only infrequently. I watched them for about a half hour, hoping to see fishing activity, which is common here on nice mornings. The two finally flew off without any more than a couple of recon flights along the lake by the adult, and no attempts. I did not get another chance to see the birds as the lake froze over solid two days later and remained that way until early this month. I have two questions: 1. Was this, as I surmised, a training exercise which simply did not achieve its goal? Do adults train their young in that manner? 2. Eagles are not obviously sexually dimorphic, except, perhaps, for size. Which parent(s) usually take the responsibility for training the young?
dragon@eleazar.dartmouth.edu (Sam Conway) (02/28/91)
In article <1991Feb26.224723.25778@newsserver.sfu.ca> palmer@whistler.sfu.ca (Leigh Hunt Palmer) writes: (a description of an immature and an adult in December). There's a few possibilities. It is unlikely that they would have been parent-and-offspring that late in the year. If anything, they were a mated pair. Bald eagles do not develop their adult plumage until their 5th year, and they are capable of breeding while still younger than that. It is also possible that the two were unrelated. Territorial boundaries break down in the winter months. It is not uncommon in such places as Alaska and Washington to see a dozen or more bald eagles all perched in the same tree. >1. Was this, as I surmised, a training exercise which simply did >not achieve its goal? Do adults train their young in that manner? The young aren't really "trained" in this fashion. The instinct to fly is inbred; however, they must watch their parents to learn the subtleties of hunting and eagle-behavior. The parents will continue to care for the young for several weeks after fledging, until the young can fend for themselves. >2. Eagles are not obviously sexually dimorphic, except, perhaps, >for size. Which parent(s) usually take the responsibility for >training the young? It is a shared responsibility once the eaglet fledges. Prior to that, the female does most of the caring. -- Sam Conway * "And if you give us any more dragon@eleazar.dartmouth.edu * trouble I shall visit you in the Chemistry Dept., Dartmouth College, NH * small hours and put a bat up your Vermont Raptor Center (VINS) * nightdress!" -- Basil Fawlty