Just like clockwork, fish hawks or ospreys have returned to begin raising a feathered family near towering skyscrapers and suburban sprawl. Sure, this isn’t pristine wilderness, far from it, but the reappearance of ospreys is one of the great natural wonders to watch for in New York Harbor.
Herald by every birder, wildlife watcher and outdoor enthusiast on either side of the estuary, the first sight of an osprey means winter is fading away and spring is slowly arriving. More importantly, ospreys are valuable indicator species for monitoring the long-term health of the Hudson-Raritan Estuary. Since the bird’s diet consists almost entirely of fresh fish, an abundance of nesting ospreys would suggests water quality and fish populations are improving to support many hungry beaks and gizzards.
After a rapid decline in population from 1950 to 1980, osprey populations have rebounded nicely due in large part to strong conservation efforts, the banning of the toxic pesticide DDT throughout the United States, and the construction of man-made platforms for nesting. Osprey numbers have increased and nesting pairs around New York Harbor are now numerous.
When birds arrive, they often looked ragged and exhausted. For good reason, migration is never an easy task.
Ospreys migrate as individuals, not in flocks, from wintering grounds in Central or South American. A recent study published by Mark S. Martell and others from a 2014 edition of the Journal of Raptor Research, shows that many of our east coast Ospreys winter in South America with smaller amounts in Florida or on Caribbean islands. As spring approaches, ospreys who winter in South America make a long distance journey past the Gulf of Venezuela to briefly rest in either Haiti, Jamaica, or Cuba, after an overwater crossing of between 400 and 700 miles. It’s a tiring flight that typically takes 27 to 40 hours and involves risky nighttime travel. Once across the Caribbean Sea, nearly all Ospreys will cross Cuba to the Florida Keys and then northward to breeding grounds. It’s an amazing journey that normally overall takes two to three weeks from start to finish.
Along the way, ospreys have many dangerous issues to deal with. One major danger is weather, especially when crossing large bodies of water. The birds can be blown off course or get caught up in a severe thunderstorm. This drains fat reserves (fuel) and puts an Osprey at risk of being too weak to continue. Humans shooting Ospreys is another major problem. This happens when hungry Ospreys try to take a fish from a private or commercial fish farm in the Dominican Republic, Haiti or Cuba. Many poor farmers do not take kindly to someone, even a bird, “stealing” a fish.
If an Osprey can survive the trip, he or she will hopefully be greeted with its partner. Ospreys mate for life, as far as we know, but go separate ways each winter. Mates do not see each other until they return to their nest in the spring. It would be a very rare occurrence if a pair ended up in the same wintering location.
Adult Ospreys arrive around late March to reuse the same nest as last year, just adding new sticks, moss and other material each season. The spring courtship for fish hawks begins a five-month period when they will raise a family, the next generation of Ospreys around New York Harbor.