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| June 13, 2018 Post 93 |
| Ospreys |
So often the men and women who study ecology seem to bring us bad news. But nature’s resilience sometimes shines through despite the pressures humans place upon the birds and animals who share this landscape with us.
Birds have often warned of ecological degradation, yet some species adapt to life in a human world. Crows have learned to drop walnuts at traffic intersections for cars to crack open. City songbirds sing shorter and lower frequency songs to be heard in a noisy environment. Some species of birds that frequent feeders have even shown changes in bill morphology, and a study in a Spanish city showed urban birds subject to heavy cat predation changed their behavior upon capture by a cat. By “playing dead” the victims improved their chances of escaping.
So sometimes science brings us a little good news from our feathered friends. The Osprey is one such example. Like that of many fish eating birds, the Osprey population took a heavy hit in the 1950s and 60’s when persistent highly toxic pesticides like DDT and Toxaphene were freely applied in a misguided effort to eradicate ‘bad’ insects. ( Often the target species of pests developed resistance while the insects and other animals and birds that preyed upon them were killed off. End result- more pests!)
Eventually, some folks began to catch on. Ecologists documented the devastating collateral damage from this crude sledgehammer approach to pest control, and use of the worst most persistant toxins was scaled back (though not eliminated). This allowed the recovery of many species of fish eating birds poisoned by cumulative pesticides in the food chain. The best known example of a recovery was that of the bald eagle- assisted through a N Y State and federal funded effort to re introduce our national symbol to its historic range. In 1976 DEC workers imported eaglets from Alaska and hand reared them in the Montezuma refuge. Those birds have since multiplied to the point where eagles along the undeveloped lake shore are now a common sight. ( Recently, I counted eight juvenile eagles hanging out on a single shoreline bluff). Another top level fish eater, the Osprey, has also made a comeback without human assistance.
The Osprey would seem to embody many virtues by human standards. These raptors are incredibly good at what they do, which is catch fish. They seem quite mild mannered, and after humans cut down all the nice big dead trees near water they used for perches and waterfront homes, they adapted by building their nests on utility poles, factory chimneys and waterfront navigation aids. The hard working Osprey is frequently robbed of its catch by other fish eaters including black backed gulls and bald eagles. More than once I’ve seen an Osprey get ‘mugged’ by an eagle. Yet they soldier on, building nests atop high voltage towers and dealing with entangling plastic fish line and other hazards of human origin.
Monofilament fish line poses particular hazards to waterbirds. On a recent canal trip I saw an Osprey being harrassed by an eagle. The hapless fish hawk had something dangling off its feet as it flew and I suspect a wad of dried weed and fish line was around its talons. Not a good prospect for the bird or its family if he doesn’t manage to free his feet. On the Chesapeake one study suggested ten percent of the Pautuxent River Osprey nests contained monofilament fish line. So if you see any monofilament lyingn around pick it up and trash it.
Ospreys are beautiful in flight. And if you can catch their aerial mating dance it’s an amazing graceful display, a three dimensional ballet aloft. They swoop, circle, dive and soar in a truly artistic sky dance. It’s much classier than the dramatic grapple of male and female eagles locking their talons and cartwheeling towards earth in a ‘death spiral’.
In the spring of 2018 a pair of Osprey set up housekeeping at the end of a very popular public pier. They built atop the eastern channel marker for Fair Haven and laid a clutch of eggs. It’s likely these were young birds, perhaps mated and raising a family for the first time. They picked a very public place for their nest, and it remains to be seen if Ospreys and humans can adapt to accommodate each other. It typically takes a chick seven to eight weeks to fledge. For the first month or so after they hatch Dad does all the hunting and if you’re lucky enough to see him catch a fish, it’s a wonder how while flying he quickly shifts his fish to an aerodynamic fore and aft position. ( The powerful eagle doesn’t bother with such details).
If the Fair Haven birds do beat the odds and raise a family they’ll all head south come fall. Some birds go as far as Central America or even down into Brazil.
Author Michael McCarthy wrote, “ There can be occasions when we suddenly and involuntarily find ourselves loving the natural world with a startling intensity, in a burst of emotion which we may not fully understand, and the only word that seems to me to be appropriate for this feeling is joy.” That pretty well describes what I feel when I see a fish hawk pass overhead or swoop down to the water for dinner.