Western Hemisphere Shorebird Reserve Network

Semipalmated Sandpiper’s Migration Astounds Scientists


Editor’s Note: This article is based on one published by Dr. Stephen Brown and Haley Jordan in the Manomet Center for Conservation Sciences’ online newsletter (July 11, 2014).

Manoment Center scientists Brad Winn (left) and Shiloh Schulte (right) with recaptured Semipalmated Sandpiper. / © Shiloh Schulte

Shorebird scientists Brad Winn and Shiloh Schulte from the Shorebird Recovery Program (SRP) at Manomet Center for Conservation Sciences returned from Coats Island in eastern sub-Arctic Canada earlier this month with an astounding discovery. Data from the geolocator (tiny tracking device) that Winn had put on a male Semipalmated Sandpiper (Calidris pusilla) last June revealed that the small shorebird flew a total distance of over 10,000 miles during the year. Even more remarkable, the journey included a six-day, 3,300-mile, nonstop flight across the Atlantic Ocean—from his breeding grounds on Coats Island to northern South America, near the border of Venezuela and Guyana. From there, he continued to Brazil, where he spent the boreal winter.

The geolocators weigh only two-hundredths of an ounce and are equipped with light sensors that record day length and the time of day as a way to track a bird’s locations throughout the year. This cutting-edge technology has been revolutionizing scientists’ understanding of several shorebird species’ migration, but the project led by Manomet Center marks the first time it is being applied to Semipalmated Sandpipers. During the 2013 field season, a team of researchers had placed 192 geolocators on this species at eight field sites across the Arctic Shorebird Demographics Network (ASDN). To date, 37 have been recovered.

Data on these devices provide insight into a previously unknown world, and are helping to solve one of the most pressing mysteries in shorebird conservation – migration routes and, in particular, where populations are being limited.

“Surveys conducted by the Canadian Wildlife Service and New Jersey Audubon Society have shown an 80 percent decline over the past 20 years in Semipalmated Sandpiper numbers within their core wintering range in northern South America,” said Dr. Stephen Brown, SRP Director at Manomet Center. “At the same time, data from the Arctic show that breeding populations are apparently stable at some sites, especially in Alaska.  We need to understand the migratory pathways of each of these birds in order to discern where the population decline is occurring, overall population trends, and wintering habits, so we can help the species’ population to recover.”

A year in the life of one Semipalmated Sandpiper (Calidris pusilla), per its geolocator data. / Map by Ron Porter

Recovered geolocators are sent to Manomet Center scientists, who are working with engineer Ron Porter to analyze and map the data on them. The male Semipalmated Sandpiper whose geolocator was the first to be recovered at Coats Island represents eastern breeding sandpipers, whose population decline may be particularly severe. The second geolocator recovered at Coats Island had lost battery power and was sent back to the manufacturer in England to help access and download the data. At least 35 additional geolocators have been recovered so far at sites in Alaska. 

“We will learn an enormous amount from the geolocators recovered in Alaska as well,” Brown said. “In particular, we will learn whether the western Arctic birds winter in the same areas of South America where aerial surveys have shown the dramatic population decline.”

The geolocator project is a partnership between Manomet Center and many other organizations, including U.S. Fish and Wildlife Service, New Jersey Audubon Society, Kansas State University, Wildlife Conservation Society, Canadian Wildlife Service, Simon Fraser University, Government of Nunavut, Université de Moncton, and Environment Canada.

Highlights from the Geotagged Semipalmated Sandpiper's Journey: 

23 June 2013:

 Brad Winn puts geolocator on shorebird at Coats Island, Nunavut, Canada

21 July 2013:

 Shorebird arrives in James Bay; fattens up for the long flight to South  America

22 August 2013:

 Leaves James Bay, flies for six days nonstop to South America

28 August 2013:

 Arrives at Orinoco Delta, on the border of Venezuela and Guyana

10 September 2013: 

 Begins "leisurely" 11-day flight along coast of northern South America to Brazil

21 September 2013:

 Arrives in Brazil for the boreal winter (austral summer)

3 May 2014:

 6 May 

10 May 

11 May 

14 May 

21 May 

 Leaves Brazil for a series of flights north:

 Stops in Cuba

 Stops in Florida

 Stops in Georgia

 Stops in North Carolina

 Stops in Delaware Bay (WHSRN Site)

2 June 2014:

 Arrives back in James Bay for the last stopover en route to breeding grounds

10 June 2014:

 Leaves James Bay

11 June 2014:

 Arrives back at its Coats Island breeding site


For more information, please contact Dr. Stephen Brown (sbrown@manomet.org), Director, Shorebird Recovery Program, Manomet Center for Conservation Sciences.