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Cape May Court House, NJ, United States

Morrison R.I.G.,Carleton University | Mizrahi D.S.,New Jersey Audubon Society | Ross R.K.,Canadian Wildlife Service Ontario Region | Ottema O.H.,STINASU Foundation for Nature Conservation in Suriname | And 2 more authors.
Waterbirds | Year: 2012

In the 1980's, aerial surveys in South America established that the main wintering areas of Semipalmated Sandpipers (Calidris pusilla) were found on the north coast of the continent, especially in the Guianas (Suriname, French Guiana and Guyana). Although population trend analyses have consistently shown declines in numbers of Semipalmated Sandpipers, especially for birds on migration in eastern North America, until now surveys had not been undertaken to determine whether such declines were reflected in numbers on the main wintering areas. Between December 2008 and January 2011, aerial surveys of major wintering areas in Suriname (3), French Guiana (2) and Guyana (1) were carried out. Results showed dramatic declines, with an overall total of only 21% of the 1980s totala decrease of 79%. A variety of reasons may have contributed to the declines and include habitat changes, range shifts, sustained hunting, or increases in predation, pollution or severe weather. Source

Van Doren B.M.,Cornell University | Horton K.G.,University of Oklahoma | Stepanian P.M.,University of Oklahoma | Mizrahi D.S.,New Jersey Audubon Society | Farnsworth A.,Cornell University
Behavioral Ecology | Year: 2016

Remote sensors such as Doppler radars are providing novel insights into the migrations of diverse animal taxa, but limits in scope and sensitivity can hamper the utility of these tools. For example, studies investigating whether songbirds compensate effectively for wind displacement during nocturnal migration have been challenged by the need to assess behavior on a large scale. In addition, these studies typically overlook the potential role low-altitude diurnal flights play in dealing with unfavorable winds. In such cases, a combination of approaches - new and traditional - may be necessary to understand behavior more completely. Here, we unite ground-based visual observations with a new radar analysis method to investigate how songbirds deal with crosswinds over the northeast United States. We find that nocturnally migrating birds experienced significant wind drift, even though they often flew at 90° or more to the wind direction. Significantly, more birds undertook reoriented diurnal flights after nocturnal wind drift, and wind influence, nocturnal migration intensity, and time of season together explained the majority of variation in counts of these "morning flights." This study shows that bird behavior during migration can be strongly shaped by the danger of wind drift and that some songbird species respond to drift with reoriented diurnal migratory flights. Knowledge of birds' interactions with wind is essential for successfully modeling migratory behavior and assessing the risks associated with changing habitats and meteorological patterns. Furthermore, an understanding of the degree to which drift defines migratory behaviors may have value across animal taxa. © 2016 The Author. Source

Burger J.,Rutgers University | Tsipoura N.,New Jersey Audubon Society
Environmental Monitoring and Assessment | Year: 2014

The health of horseshoe crab (Limulus polyphemus) eggs is important not only to maintain horseshoe crab populations, but because they are a resource for higher trophic levels, such as fish and shorebirds. We examined the concentrations of arsenic, cadmium, chromium, lead, manganese, mercury, and selenium in the eggs of horseshoe crabs from Delaware Bay (between New Jersey and Delaware, USA) in 1993, 1994, 1995, 1999, 2000, and 2012 to determine if there were significant temporal changes and if levels appear to pose a health risk to the crabs themselves, or to predators that consume them. All metal levels declined in horseshoe crab eggs between 1994 and 2012, although the declines were much less consistent for lead and chromium than that for mercury and cadmium. Levels of contaminants found in these eggs are well below those known to cause adverse effects in the crabs themselves or to organisms that consume them, such as migrating shorebirds. © 2014, Springer International Publishing Switzerland. Source

Gratto-Trevor C.,Environment Canada | Morrison R.I.G.,Carleton University | Mizrahi D.,New Jersey Audubon Society | Lank D.B.,Simon Fraser University | And 2 more authors.
Waterbirds | Year: 2012

The Semipalmated Sandpiper (Calidris pusilla) is a small, abundant shorebird that breeds primarily in sub-Arctic to mid-Arctic habitats across the Nearctic and winters principally along the northern and central coasts of South America. No subspecies have been described and little is known concerning their genetics. However, birds show a cline in bill length across the Arctic, with longest bills in the east and shortest in the west. There appear to be several 'steps' in the cline, suggesting a division into eastern, central and western breeding populations. Since females average longer bills than males in a breeding population, there is considerable overlap of bill lengths at migration staging areas. Based on bill length patterns and sightings and recoveries of marked individuals, most western breeders migrate south through the prairies, along with some birds from central Arctic populations. The remaining central Arctic breeders, and all eastern Arctic birds, migrate south through the north Atlantic Coast of North America, particularly the Bay of Fundy. Western Arctic breeders appear to winter farther west in South America than eastern breeders, although there is considerable mixing among populations in French Guiana and Guyana. In spring, birds from the eastern Arctic migrate north through the U.S. Atlantic coast, including Delaware Bay. Central and western Arctic breeders primarily migrate north through the interior of North America. Therefore, central Arctic breeders in particular demonstrate an elliptical migration pattern. Source

Johnson B.J.,Rutgers University | Johnson B.J.,College Farm Road | Munafo K.,New Jersey Audubon Society | Shappell L.,Rutgers University | And 4 more authors.
Urban Ecosystems | Year: 2012

This study investigated the impacts of urban wetlands and their adjacent residential environments on the transmission dynamics of West Nile virus (WNV) within the state of New Jersey (USA). A working hypothesis was that urban wetlands decrease the local prevalence of WNV through the dilution effect from increased bird diversity, and through relative reductions in the numbers of competent avian host and mosquito species commonly associated with WNV. Surveys of mosquito and bird communities were undertaken at six urban wetlands and their adjacent residential environments over two seasons (2009, 2010). The community compositions of both avian and mosquito species differed significantly across habitats, and over relatively short geographical distances. Residential areas contained significantly higher proportions of WNV-competent mosquito species (31.25 ± 5.3%; e. g. Culex pipiens and Culex restuans), and WNV-competent avian host species (62.8 ± 2.3%, e. g. House Sparrow and American Robin) when compared to adjacent urban wetlands (13.5 ± 2.1%; 35.4 ± 2.1% respectively). Correspondingly, WNV infection rates within local Culex spp. populations indicate that WNV was more prevalent within residential areas (28.53/1000) compared to wetlands (16.77/1000). Large urban wetlands (≥100 ha) produced significantly lower weekly WNV infection rates in local Culex spp. (6.67 ± 2.84/1000) compared to small (<15 ha) wetlands (22.57 ± 6.23/1000). Avian species richness was also influenced by patch size. Large urban wetlands contained significantly more species than small wetland patches. These results confirm that the community compositions of mosquito and avian hosts are important drivers in WNV infections, and that the ecological conditions that favor transmission are more strongly associated with urban residential environments than with adjacent urban wetlands. © 2012 Springer Science+Business Media, LLC. Source

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