Osprey: Nature's ambassadors return

Ospreys are starting to turn up at many coastal locations all over the Cape.

These large, rangy hawks, with a 6-foot wingspan, are migratory birds that have been observed arriving on Cape Cod as early as March 3, but mostly in the third week of the month. The osprey is the most common and well- known bird of prey in the world, but it hasn’t always been that way in the U.S.

Back in 1970, only 10 pairs were found nesting in Massachusetts. These birds, also known as fish hawks or sea hawks, were very susceptible to DDT, a pesticide used by farmers back then to kill the insects that munched on their crops. However, DDT didn’t break down and become a harmless chemical. It ran off into streams and then rivers and up the food chain and eventually was found in the bigger fish that osprey caught. It was so concentrated at this point that although it didn’t kill the ospreys, it made the birds' egg shells so thin that they cracked very easily. This led to a very drastic population decline. As you may know, there was a 1972 federal ban on the use of DDT and today we have more than 200 ospreys just on Cape Cod.

Much more is known about the osprey than other raptors because of its behavior to tolerate humans close by its nest. It is the only North American hawk that dines on fresh fish. I’m sure if you have ever fished, you can fully appreciate this factoid. The osprey is successful at catching fish 25 percent of the time. Their average hunting time, from the moment they see a fish until they dive for it, only averages about 12 minutes. Fishermen, can you relate?

One of the obvious questions here is where do they come from? This was answered when a tagged bird that left Martha’s Vineyard after nesting successfully turned up in French Guiana, South America. Most ospreys over the course of their 15- to 20-year lifespan can travel up to 160,000 miles.

Aside from some of their amazing natural history, ospreys are also known as nature’s ambassador. Why? Because they’re large, visible migratory birds; they allow human activity near their nest; they mate for life; and they have made a remarkable population recovery, with some human help in the form of a federal ban on the toxic chemical DDT and the installation of many man-made nest poles. I’m sure that Woods Hole Oceanographic Institution's osprey-cam and the Cape Cod Museum of Natural History osprey-cam also helped. Osprey-cams are nest poles outfitted with cameras to observe the birds' behavior, including egg-laying and fish being torn up by mom and her nestlings.

Watching an osprey rebuild its nest, lay eggs, feed its young and patiently wait for its fledglings' first flight definitely makes one appreciate the secret of slowing down, watching and waiting.

Last year, near the end of March when I was volunteering in Cape Cod Museum of Natural History’s Marshview Room, I was watching the osprey-cam and was amazed to see the female rearrange a stick that the male had spent 20 minutes placing in the nest's perfect spot. I was equally surprised, even shocked, to see the male arrive at the nest with a freshly caught fish, only to have the female tug on it and eventually seize it and fly away. The male was still on the nest looking somewhat befuddled. 

As I reflect on watching our nature ambassador, I wonder about our role in nature. Can we reap all the benefits of a strong connection to nature and our natural heritage and still maintain an adversarial role, causing multiple wildlife extinctions? Were we put on earth to eventually develop a bond with the natural world while simultaneously polluting land, sea and air? Only time will tell, so please do your part. 

Hope you see an osprey soon — they always return to the nest they had the previous year — and begin developing some nature ethics of your own, or at least begin by creating a strong connection with nature.

UPDATE: Sightings of accidental birds included a Mew gull and yellow-billed loon on Race Point in Provincetown and a snow goose at Fort Hill in Eastham. Sightings of migrants included ospreys at Salt Pond in Falmouth, Sea Gull Beach in Yarmouth and Fort Hill; piping plovers at Sea Gull Beach and Red River Beach in Harwich; killdeer on Bell's Neck in Harwich and Race Point; eastern Phoebes at Fort Hill and Mashpee Pond; American oystercatchers at Sea Gull Beach and Bournes Pond in Falmouth; and tree swallows at Bank Street Bogs in Harwich and Mashpee Pond. 

— Phil Kyle writes about birding every week for The Cape Cod Times. He spent a 30-year career as a biology teacher in private and public high schools and was formerly the education director at South Shore Natural Science Center in Norwell, head naturalist at Cape Cod Museum of Natural History in Brewster and an interpretive park ranger at Cape Cod National Seashore. He is past president of The Cape Cod Bird Club, and in his semi-retirement he works summers as head naturalist with Barnstable Harbor Ecotours. He can be reached at archeopt@yahoo.com.