After reaching its peak in early October, osprey migration around New York Harbor is slowing down. Fewer and fewer flying ospreys are being spotted, but sights of migrating ospreys will continue well into November from young birds that were raised far up in New York, New England and Canada. The fall migration is still under way for ospreys, as colder temperatures and shorter days signify the coming winter.
The osprey (Pandion haliaetus) also known as a fish hawk or sea hawk, is a large diurnal, fish-eating raptor. Chances are pretty good you have seen one flying around New York Harbor this fall in places like Sandy Hook Bay, Jamaica Bay, Raritan Bay and other watery areas where they nest. You may not have even known you had spotted one. At quick glance a single osprey sort of appears like a large gull, similar to a Lesser black-backed gull, especially in flight.
But ospreys are no gull. They are superb fishers. Most avian field guides indicate that 99 percent of an osprey’s diet consists of live fish, including menhaden or bunker, flounder and bluefish. It is the only raptor that relies so much on fishing for living.
According to the Cornell Lab of Ornithology, ospreys catch a fish on at least one in every four dives, with success rates sometimes as high as 70 percent. The average time the bird spends hunting before making a catch is about 12 minutes. A much better success rate than most weekend warriors around New York Harbor that try their luck catching a fish with a rod and reel.
Ospreys that nested around New York Harbor and in many parts of North America are migratory. Over the years wildlife biologists have tracked those that have nested in New Jersey and Jamaica Bay, NY with miniature satellite transmitters during fall migration. Amazingly the bird’s journey took them to Cuba and other islands in the Caribbean, Venezuela, Colombia, and Brazil’s Amazon River basin. A mind-blowing voyage that travels over land, ocean, and sea; and fishing all the way!
Ospreys that nested in New York Harbor can take several routes southward during fall migration, but frequently will follow the coastline to Florida or fly directly over the Atlantic Ocean to the Bahamas, Cuba and Hispaniola. From here, they will hop to islands in the Bahamas or Caribbean to feed and rest before eventually setting out to the Venezuelan coast. At this point, many ospreys have already covered over 2,000 miles. Some have not even completed their long winged journey and will continue flying to eventually spend the winter along remote rainforest rivers in the Amazon River basin in South America.
The Cornell Lab of Ornithology tells us that a single osprey may log more than 160,000 air miles during its 15-to-20-year lifetime travelling from their wintering homes in the tropics to their breeding homes in North America. For example, during thirteen days in 2008, one osprey flew 2,700 miles, from Martha's Vineyard, Massachusetts, to French Guiana, South America.
Even more remarkable than fall migration is that every osprey will migrate alone. Although many people believe that all birds migrate together in flocks, this isn't true for raptors and especially for ospreys. When ospreys migrate, they leave as individuals and migrate south entirely on their own, including juveniles that were born the previous summer.
Sometime in late August, mother osprey will typically migrate first, becoming less and less of a presence around the nest before finally taking off. Father osprey will remain a few days or weeks behind to help the young lean hunting skills they will use for the rest of their lives.
By early September, most if not all resident osprey parents around New York Harbor will have left the nest. Their role as parents is complete. They will migrate south leaving their children on their own to continue learning about the art of fishing. Only the smart and strong will survive.
Ultimately, those adolescent ospreys that survive this far will increase their energy stores before starting their first long winged journey single-handedly down south. The young ospreys will amazingly have to fly thousands of miles to a place in the tropics they have never been before unaided by parents, a map or computer.
It’s not an easy flight. There are many dangers for young first-time ospreys. They can get hit by a car or ship, get tangled up in power lines, get shot at by an angry aquaculture farmer, get blown off course by storms and hurricanes, and even get lost when crossing the open ocean. The good news is that statistically those young ospreys that survive their first year have a better chance of surviving future migrations.
What drama! Fall migration season is an exciting time right here in New York Harbor. If you spot an osprey on the move, please respect the bird and watch from a distance. We wouldn’t want to cause any more stress to a bird in a long, demanding journey before cold weather sets in and freezes shallow waterways to deny this fish hawk their major food source – fish.
To view more pictures, video, or stories of wildlife around Sandy Hook Bay, Raritan Bay, and Lower New York Bay, please visit my nature blog, NY Harbor Nature at http://www.nyharbornature.com