Hi all,

On the question of bald eagle aggression toward blue herons, I haven't seen that. However, I can relay an experience with an osprey and great blue heron on my (20th) annual Deschutes River (central Oregon) float trip last year with two longtime friends.

The Deschutes is a world-class special-regulation trout river with a very healthy population of wild rainbow trout and a few other fish species. Consequently, it also has very healthy populations of fish-eating bird species, including at least two types of mergansers, belted kingfishers, great blue herons, an occasional bald eagle and in particular ospreys - which have been abundant and substantially increasing in numbers for the last five or ten years based on our observations.

Last year on the second day of the trip we were awakened at dawn by a hideous and very loud screeching/gronking sound coming from the river. We sat bolt upright on our cots (sleeping under the stars, as the weather there is very hot/dry in midsummer) and quickly saw the source of the noise. An osprey was dive bombing an adult great blue heron (GBH) with an intent that gave every appearance of being to inflict injury, not just simple harrassment. The GBH was the source of the noise, appeared to be duly panicked and was attempting to make a getaway upriver. (A humorous mismatch analogous to a lumbering biplane trying to deal with a fighter jet.) The chase and racket continued for perhaps two hundred yards until the osprey finally broke off the attack and the GBH shut up. There was an active osprey nest on a pole less than fifty yards from the river near our camp, with one nearly-fledged chick, and so we presumed the osprey's motive was probably nest protection. Although!
we had
seen many osprey and GBH's on previous trips we had never seen anything like this behavior previously. This particular GBH must have been a slow learner (or another bird moved into the former's fishing grounds) as the same scenario repeated itself the next morning. After that, lesson apparently having been learned, all was calm for the remainder of our stay there.


John Tubbs
Snoqualmie, WA
johntubbs at comcast.net
www.tubbsphoto.com