CONTENTS of the Osprey Pages

Introduction

    In 1969, when I began studying the birds of prey on Martha's Vineyard, there were two pairs of Ospreys on the Island. By 1992, thanks to the efforts of Gus Ben David, then director of Mass Audubon's Felix Neck Wildlife Sanctuary, and a large number of Osprey devotees working under his guidance, the population had increased to over 70 pairs. In the early to mid-90s, the Ospreys suffered a significant decline in their nesting success, but have since shown strong signs of recovery. Gus monitored the population through the '94 season. I picked up the census again in 1998 and, with the help of some graduate students and a number of Island residents, have monitored the number of breeding pairs and the number of young fledged each year. (Details)

    In 2000 I began collaborating with Mark Martell on his studies of Osprey migration. A small (and rather expensive) transmitter attached to an Osprey's back enables us to track a bird daily as it migrates. We tagged two Ospreys in 2000-2001, and since then have deployed transmitters on 31 more, mostly on Martha's Vineyard. Beginning in 2004, we have been concentrating on following young birds on their first migrations. This year (2009) will mark the end of our studies of juvenile Osprey migration and the beginning of a study of adult males' hunting behavior. (Details) 

    In 2004 one of my graduate students, Jennifer Rettew, began studying the Vineyard Ospreys for her M.Sc. thesis. She is watching a series of nests to quantify and identify the fish that are being brought in by the parents. She will be looking for differences in diet and reproductive success between pairs from different parts of the Island. 
     Working with the BBC on their upcoming documentary series, "Incredible Journeys," we tagged five new birds--two adults and three young of the year. (Details)

     In 2005 Jennifer spent her second and final season watching 16 Osprey nests, focusing on the relationship between feeding rates, sibling aggression, and nesting success. She successfully defended her M.Sc. thesis in the spring of 2006.
     Spurred on by our success with tagging young birds in '04, I decided to focus all my attention on satellite tagging young birds. That year we tagged two young--one on the Vineyard and one in Rhode Island.

     In 2006 we tagged three birds in Delaware in or around Cape Henlopen State Park, one in Rhode Island, and a single bird on the Vineyard. One or the young birds tagged for the BBC, Jaws, returned to the Vineyard for the first time.

     In 2007 we tagged five birds again--two in Delaware and three on Martha's Vineyard. Jaws, from the class of '04 returned for his second trip home, and Homer, tagged near Little Homers Pond on the Vineyard, returned for the first time. This was the first year we used GPS enabled transmitters, which opened up a whole new world of research possibilities. The previous transmitters were accurate enough to follow migration, but not to follow the daily hunting movements of individual Ospreys.

     In 2008 we tagged seven young Ospreys--one in South Carolina, one in Delaware, two on Cape Cod, and three on Martha's Vineyard. 

     In 2009 we have initiated our studies of adult hunting behavior by tagging 4 adult males--3 on the Westport River, just west of New Bedford, MA, and one on Nantucket Island. If all goes well, we will outfit 8 young with transmitters in July and August.