Back Cover - On the Banding of Eagles

ISSUE : Issue 31

Published by Ronald Caplan on 1982/6/1

On the Banding of Eagles Eagle Photographs and a Talk by Biologist Dave Ham's Eagles are a raptorial bird which doesn't really migrate, so they're under provincial responsibility, (By raptor, we mean,,..) Owls, hawks, that sort of thing. Eagles are included. Birds of prey, mostly. This is a general term you could use for them all. (And when we say they don't migrate.,.?) The adults don't--the adults go as far as they need to go to find open water. The young ones, on the other hand, have been known to go much further. We had a banded bird show up in Maine a couple years ago. They couldn't identify the exact bird--they couldn't see the number on the tag--but it was identified--so that's quite a distance for a young bird to go. Concentrations of young birds have been seen in the fall in Lake Ainslie and around the Causeway, and they go down to the mainland. The Shubenac- adie River on the mainland has huge popula? tions of immature birds in the winter months. They've counted 80 birds feeding a- long that river at one time. You know, that's astronomical populations. And most of those would be young of the year from this area and other areas. And young birds that we banded as nestlings have shown up in our two winter banding areas on the main? land- -just outside of Halifax, Martinique Beach, and in the Valley. (But they don't migrate the way we usually think of birds migrating.) No, They stay as close to their home territory as they can. But as that freezes over, which it often does, they migrate further away to open wa? ter. So they'll be along the coast more than they would normally. Or they'll be any? where there's open water, because they are a fish-eating bird, and mainly a scavenger bird--dead fish--and that washes up any? where there's open water. And you'll see them on a carcass of something in the win? ter. And around plants where they have a lot of carcasses thrown out--a big farm or where they're doing butchering--you'11 see them around that area. You see them quite a bit around Nickerson's fish plant in North Sydney; you'll often see some on the ice o- ver there. In your article (Issue 6, Cape Breton's Magazine, "The Life History of the Northern Bald Eagle") Herrick was say? ing that they only have one nest and they stay at that nest. Recent work has shown that they may often have two nests within a territory. (In the same season?) No, no. But they'll switch nests. They may stay on one 3, 4, 5 years, and then switch to the other one. It could be disturbance--that could be the reason why they switch. Or possibly it could be because of a parasite buildup in that nest. It's hard to say. But they'll usually be within a half mile of the nest as much of the year as they can. Now there's two ways of banding eagles. One is to climb the nest tree and band the young. The other is to put bait out and have little nooses on the bait, and the bird comes down to feed on the dead carcass and gets caught in a noose. And then we go and band it. In the springtime, we only do the nest banding. The only time you could possibly get an eagle to come to bait very readily would be in the wintertime, when they were a little hungrier. We don't real? ly bother with that on Cape Breton, because there aren't the concentrations of young birds that would be easily tricked into com? ing to the bait. The adults are there, and like I say, they're around the nesting ter? ritory, and they do occasionally come to carcasses--but they seem to be much more leery to come to one that we've'doctored. I think in the years they've been'doing this on the mainland, they've only captured one or two adults. And we're mostly after the immatures, See, it takes them four years of immaturity be? fore they become an adult. And we don't know where they go during that time, You don't see them around the nesting territor? ies. That's something we want to find out-- just where they go, and what the success rate is of the young, how many of them do make it to adulthood.

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Cape Breton's Magazine