Post-DDT Recovery of Osprey (Pandion haliaetus) Populations in Southern New England and Long Island, New York, 1970–2013
The Osprey (Pandion haliaetus) population nesting between New York City and Boston, Massachusetts, collapsed from approximately 1000 pairs in 1940 to 109 in the early 1970s. In the 1970s, within five or six years of the cessation of DDT use in the region, the Osprey population began recovering. The recovery was asynchronous across the region. Current (2013) distribution and numbers differ dramatically from those of the pre-DDT period. Colonies on Narragansett and Mount Hope bays in Rhode Island, the Connecticut River estuary, and on Gardiners Island, New York, failed to recover their former remarkable densities. Osprey populations expanded from eastern to western Long Island, New York. In Connecticut, Ospreys now occupy the entire coastline and are nesting inland. A new concentration of Ospreys has become established in southeastern Massachusetts on the Westport River, the islands of Martha's Vineyard and Nantucket, and most recently, on Cape Cod. From this area, the species' range has gradually expanded northward. The population in Massachusetts is now contiguous with the New Hampshire population, and pairs are nesting west of the Connecticut River. The current population in southern New England easily exceeds 1200 pairs and is predominantly (ca. 95%) nesting on human-made structures either erected as nest platforms or co-opted by Ospreys as nest support structures. La población de Pandion haliaetus nidificando entre la ciudad de Nueva York y Boston, Massachusetts, colapsó de aproximadamente 1000 pares en 1940 a 109 a comienzos de la década de 1970. En dicha década, en cinco o seis años de cese en el uso de DDT en la región, las poblaciones de P. haliaetus comenzaron a recuperarse. La recuperación fue asincrónica a lo largo de la región. La distribución y los números actuales (2013) difieren dramáticamente de aquellos del periodo pre-DDT. Las colonias de las bahías de Narragansett y Mount Hope en Rhode Island, el estuario del Río Connecticut y en Gardiners Island, Nueva York, no pudieron recuperar sus notables densidades pasadas. Las poblaciones de P. haliaetus se expandieron desde el este hacia el oeste de Long Island, Nueva York. En Connecticut, P. haliaetus ahora ocupa la línea de costa completa y está nidificando tierra adentro. Una nueva concentración de individuos de P. haliaetus se ha establecido en el sudeste de Massachusetts en el Río Westport, las islas de Martha's Vineyard y Nantucket y más recientemente en Cape Cod. Desde esta área la distribución de la especie se ha expandido gradualmente hacia el norte. La población en Massachusetts ahora es contigua con la población de New Hampshire y las parejas están nidificando al oeste del Río Connecticut. La población actual al sur de Nueva Inglaterra fácilmente supera las 1200 parejas y nidifica predominantemente (ca. 95%) en estructuras hechas por el hombre, tanto las construidas como plataformas para nidos como aquellas que P. haliaetus utiliza como estructuras de soporte para sus nidos.Abstract
Resumen
Distribution of nesting Ospreys in southern New England and Long Island, NY, ca. 1940 (cross hatching) and in 2009 (solid outline). The three major pre-DDT colonies are indicated on the map: GI = Gardiners Island; CR = Connecticut River Estuary; RI = Mount Hope and Narragansett bays.
Three-point running means of the number of young fledged/active nest in our larger regional populations (LI = Long Island, New York; CT = Connecticut; RI = Rhode Island; MA = Massachusetts; MVY = Martha's Vineyard, Massachusetts). “B-E” indicates the reproductive rate necessary for a stable population as calculated by Spitzer (1980).
Average reproductive rate (young/active nest) by decade with Martha's Vineyard data separated for the 1970s but included in all other decades. Whiskers represent maximum and minimum values, boxes represent the mean ± 1 SD. Samples with the same letter are not significantly different (P > 0.05) in pair-wise Tukey HSD tests. Data from the 1970s for Martha's Vineyard were not included in the statistical comparison.
Population growth in regional populations measured as a percentage of the number of breeding pairs in that region in 2001. (LI = Long Island, New York; CT = Connecticut; RI = Rhode Island; MA = Massachusetts; MVY = Martha's Vineyard, Massachusetts; WPT = Westport River, Massachusetts). Numbers after each label are the number of pairs for that region in 2001.
Estimated numbers (billions of fish) of Atlantic menhaden based on the Atlantic States Marine Fisheries Commission Beaufort Assessment Model (BAM) (after ASFMC 2012a).
Percentage of known Osprey nests on nest platforms across the study area over time. (WP = Westport River, Massachusetts; MVY = Martha's Vineyard, Massachusetts; RI = Rhode Island; CT = Connecticut; LI = Long Island, New York).
Contributor Notes
Associate Editors: Ian G. Warkentin and Brian E. Washburn