Backyard and Beyond

Alan F. Poole’s Ospreys: The Revival of a Global Raptor

In my half century life, there has been a great recovery of Osprey populations after ruthless persecution and even more ruthless chemical warfare. Luckily, this long-distant migratory bird is highly adaptable. They readily take to artificial nesting spots: 3 of 5 pairs in North America nest on human-made structures, many deliberately placed for them.

Pandion haliaetus is found around the world in four subspecies. The largest concentration of these fish hawks is found (in breeding season) in the Chesapeake Bay region. Driving across the Potomac River Bridge, for instance, is remarkable for sightings of flying birds, and nesting sites. Pandion haliaetus carolinensis is the subspecies we’re familiar with in North America; genetic evidence suggests the birds spread out around the world from North America during the Pleistocene.

Curiously only the Australian/New Guinea population is a southern hemisphere breeder. Others winter in the southern hemisphere (South America, Africa, India, SE Asia) but don’t breed there. Interestingly, not so much is known about the Japanese population. The cover photo is of one of the least populous subspecies, P. h. ridgewayi, found in Cuba and the coast of Belize.

Hazards abound. Fish farmers in winter months take a toll. The birds are a bellwether for toxins; our chemical civilization continuously releases new poisons into the ecosystem, and tens of thousands of the old ones pre-date testing requirements. Eastern Europeans still shoot them; the generally good news on recovery from the UK (over a million people have visited an osprey nest site in Scotland since 1959), France, Germany, and Scandinavia is not seen in Poland and nearby countries. The Mediterranean crossing during migration still bristles with guns.

Osprey’s have 8-9 feet of intestine. Fish make up 99% of their diet. They’ll eat almost any fresh or salt water fish, but particularly like the species that school in shallow waters.

About half of each year’s young don’t make their first birthday. For those that do make it, they usually take an extra year in their wintering areas before returning north to breed. So a bird born this year won’t return until 2021. Adults, of course, return every year, often unerringly to the same nest site. Mates spend the winter apart. Their winter grounds are often very contained, just a few square miles. The trip back north in early spring is faster than the trip south, when they often stop to rest up and eat. (Females in particular are pretty weak after breeding season.) Cuba is the route south of the majority of birds in the east.

Alan F. Poole has spent years studying these birds. He writes a good book. Pictures from a banding I helped out at in 2010.
Another in 2012.
And again.

In 2016, a pair of Osprey nested on a light tower at the South Brooklyn Marine Terminal, sorta-kinda in sight of my apartment. There were young, but no repeat performance.
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Trump reminds us how fragile such victories as the Osprey recovery. An authoritarian party of profiteers-in-death can sweep away the good works of the past. He’s trying to gut science from the EPA and other parts of government at the behest of the plutes, polluters, and future-killers. The Republicans are the party of death for humans, animals, and planet. In a very important action this week, the rape-minded Injustice, B. Kavanaugh, signaled his Federalist Society mission loudly and clearly: to strip the ability of federal agencies to regulate.