Migrant birds’ return offsets dreaded tax day

By Chris Corio, Special to the News
Posted April 16, 2010, at 7:30 p.m.

The middle of April can be a trying time for many people as the dreaded “tax day” approaches. However, for birders, this can be offset by the waves of migrant birds returning here to breed. I knew one person who marked April 15 as the day the osprey returned to their nest near her residence — at least one good thing about this particular day, she said.

I’d been watching out for osprey for weeks, beginning back in March when an early bird was seen in the state as a likely result of one of the storms traveling up the coast. During my walks to Bug Light Park in South Portland, and traveling back and forth over the Casco Bay Bridge, I looked at the nests intently, hoping to see a returned occupant.

I’d also been keeping tabs on the Bradbury Mountain Hawkwatch count, which is conducted seven days a week from 9 a.m. to 5 p.m., starting on March 15 and ending on May 15. Increasing numbers of osprey were being tallied as they passed this lookout site, so I felt for sure that “our” osprey would be here by now.

I grabbed the friend of mine who marks the beginning and end of the season by the osprey’s return and departure, and we walked down to Spring Point to check. Sure enough, two ospreys were perched side by side in the bowl of the nest.

We were both glad to see the birds, which could be the same pair that had nested there last year and in years past. Pairs who have bred successfully at a certain location often will return to the same nest year after year; this is referred to as “nest site fidelity.”

According to The Birds of North America species account, members of a mated pair may winter separately but reunite when they both return to their previous nest site. Here they re-establish their bond and begin adding new material to the already-existing nest.

Here at Spring Point, the nest is located atop a specially constructed platform, built expressly for the birds years ago when they lost their previous nest on some old piling timbers. According to the BNA, nests on these types of structures tend to remain relatively small in diameter and depth. Nests built in solid trees or on the ground (as can happen on mammal-free islands) can become as much as three or four meters deep with a diameter of two meters — capable of supporting the weight of a human.

In addition to the nesting osprey to enjoy all summer, there is an added — and spectacular — bonus of another raptor that has come to nest in the area. A pair of peregrine falcons has returned for the second year in a row to a location near me.

I had been watching the area for quite some time, but oddly enough, the first time I caught sight of one was while driving over the Casco Bay Bridge.

I don’t know what made me glance up through the windshield, but in those few seconds I saw one of these beautiful falcons flashing by with quick, powerful wing beats in pursuit of a herring gull. I was never able to see the outcome, what with having to keep an eye on the road and on the traffic around me, but I intend to stake out the area in hopes of seeing more of these birds in action.

For more information on the nesting pairs of osprey and peregrine falcons in the state — and to view live Web cams of the nests — visit The Biodiversity Research Institute at www.briloon.org.

http://bangordailynews.com/2010/04/16/outdoors/migrant-birds-return-offsets-dreaded-tax-day/ printed on July 24, 2014