Thursday, March 28, 2013

Another First - The Osprey

Spring struggles to arrive. Winter has done its best to thwart us: snow, cold, wet, dark and gray. Yet spring does arrive; birds return; amphibians emerge; plants begin to break ground and their buds swell.
Many spring events are triggered by daylight and day length; others respond to warmth. Some need both. Avalonia volunteers spend a lot of time outdoors, all year long, and we respond to day light and warmth too. As we are out and about, we are looking for signs of spring and continue to count “FIRSTS”.

                                                        Photo by Rick Newton

Birds that have spent the winter in southern climates don’t know what the weather is like up here, so they rely on day length to trigger their impulse to return north. Of course, a nice southerly breeze is a big help and frequently in mid to late March we experience a period of warm teasing weather. It is during these times we look for our returning birds, and the most eagerly awaited are the osprey. Many of the osprey from our area winter in Central and South America. As the hours of daylight begin to increase and reach equality with hours of dark at the Spring Equinox, these birds are making their return. Here in Southeastern CT we count on them arriving around St Patrick’s Day, give or take a few days. Ospreys are very loyal to their nest sites. While males and females do not spend the winter together, banding records and studies have shown that bonded pairs will return to the same nest site, usually at different times, and one will wait for the other to renew that bond for another year.
Despite the strangle-hold of winter, the first osprey was reported locally on Saturday March 16th. Right on time. As “fish hawks” they rely on open water to find food. While the ice has melted from most bodies of water, fish often tend to swim deeper to find warmer temperatures. If the weather continues cold with freezing nights, the newly arrived osprey may have a hard time finding food. However, as the next weeks go by, temperatures are bound to warm up. With southerly breezes, more osprey will return to their nest sites along the shore, and there will be plenty of food.

                                                        Photo by Rick Newton

Take some time to look for the very visible platforms used for nesting. Decades ago, osprey nested on big dead trees, called snags, along marsh edges, and along the shore. Those sites have nearly disappeared and now osprey rely almost exclusively on man-made platforms for nesting. They will reuse and enhance and enlarge the nest each year, some reaching quite impressive sizes. After the super storm Sandy last fall, and the blizzard and wind storms this winter, the returning osprey may have more work to do.

Now that the weather is finally warming, go find a nest site, and observe from a distance. Several Avalonia properties in Stonington have osprey nests, including Cottrell Marsh, Continental Marsh, and Paffard Marsh which may have the most visible one. There is also one just over the railroad tracks very visible from the Knox preserve. Many others are on private or state properties all along the shore. Enjoy the return of the osprey!

Written by Beth Sullivan

Learn more about the osprey at the Cornell Lab of Ornithology

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