What good do ospreys serve?  This isn’t an uncommon question from hikers who may have slept through their biology classes.  When the question was asked, we were looking over the Scallop Pond Preserve in late April with an occupied osprey platform in the distance.  In response, I mumbled something ecological about keeping the lower trophic levels of the food chain in check and, in general, without top carnivores an ecosystem could become less diverse with just a few species dominating the community.  So, such noble birds help maintain overall biodiversity.  I also alluded to the aesthetic qualities of this beautiful large bird of prey.  I even mentioned that the osprey being a top carnivore has no competitors. That was soon refuted by Joan Garro’s observation of a red-tailed hawk relentlessly pursuing an osprey in an effort to steal an alewife from the osprey’s talons.  Kleptoparasitism - a means by which animals obtain limited resources - is not unknown among sea birds (gulls and terns), but I haven’t ever seen this competition between these two top guns. 

During our next hike, in late May, we came upon a large flock of black-crowned night herons and a group of egrets as we walked along Turtle Cove at Big Fresh Pond.  We anticipated those birds but not the bald eagle perched above one of the egrets on the far shore of the cove. This was a first for me at Big Fresh Pond, and although top carnivores are always less numerous than their prey, seeing a relatively rare one is an encouraging sign that our local ecosystem is sound and that we can anticipate such top predators being more commonly observed during future hikes. Keep hiking and watching.