Iowa Pectoral Sandpiper Stopover Study

Welcome to the Pectoral Sandpiper (Calidris melanotos) stopover ecology study Web resource! This is a collaborative effort between Iowa State University, The U.S. Army Corps of Engineers (Sustainable Rivers Program [SRP]), and the Iowa Department of Natural Resources to track migrating Pectoral Sandpipers at an Iowa stopover site (Red Rock Lake) during fall migration.

The Pectoral Sandpiper breeds across the Arctic in western North America and eastern Siberia and winter primarily in central and southern South America (Farmer et al. 2020). It is a common spring and fall migrant in Iowa. In spring they occur from late March through late May and in fall from early July through late October. Fall concentrations can number in the thousands in late July and August. Consistent fall stopover locations in Iowa include Red Rock and Saylorville reservoirs in central Iowa, Union Slough National Wildlife Refuge in north-central Iowa, and Hawkeye Wildlife Area in eastern Iowa, as long as habitat conditions are ideal. Little is known about their stopover dynamics in Iowa or the Midwest (Murphy and Dinsmore 2014).

The Sustainable Rivers Program is a collaborative effort between the U.S. Army Corps of Engineers and The Nature Conservancy that aims to learn how environmental flows can be incorporated into reservoir pool management strategies. Environmental flows are scientific prescriptions for the timing, quality, and quantity of water flows needed to sustain environmental function and species' habitat (The Nature Conservancy 2020). Environmental pool management began at Red Rock in fall 2021 with the goal of dropping the pool beginning in late July to benefit migratory shorebirds (Calomeni et al. 2022). The plan calls for a 1.5 foot drop ending in late August, followed by a pool raise in early September when most shorebirds have departed. The exposed mudflats are rapidly colonized by vegetation, which when reflooded in fall provide food and cover for waterfowl and other wildlife. 

Our research group at Iowa State University studies the population ecology of birds and other taxa. This particular project is led by Victoria Fasbender (M.S. student in my lab) with support from Iowa Department of Natural Resources and U.S. Army Corps of Engineers staff. For this study we use the Pectoral Sandpiper to investigate how long they stop over at Red Rock, how they make use of the varied habitat that is available because of the SRP environmental flows, and where they go once they depart our area.

Pectoral Sandpiper in central Iowa. Photograph by Stephen J. Dinsmore.
Pectoral Sandpipers in fall at Red Rock Reservoir, Iowa. Photograph by Stephen J. Dinsmore.


Project objectives:

  1. Estimate residency time for the Pectoral Sandpiper during fall migration.
  2. Characterize local movements of the Pectoral Sandpiper at Lake Red Rock in response to SRP environmental flows.
  3. Share bird tracking data with the public (this Web age).

Field methods

Pectoral Sandpipers (Calidris melanotos) are captured at Red Rock Lake with the use of mist nets, which is a standard shorebird capture technique. We use 60 mm mesh mist nets that are 12 m long and 3 m tall and deploy them in areas frequented by foraging shorebirds. Our research group has successfully used this approach with this species at a site in northwestern Iowa in 2012, and also with other migratory shorebirds at Saylorville Lake (2016-2020) and Lake Red Rock (2021-2022). We collect basic morphometric data for all captured birds, including flattened wing chord, tarsus length, and body mass and use established formulae to assign sex to each individual (wing chord >133 mm is a male and <133 mm is a female).

Pectoral Sandpiper in mist net. Photograph by Stephen J. Dinsmore.
Victoria Fasbender with a tagged Pectoral Sandpiper. Photograph by Stephen J. Dinsmore.

Each Pectoral Sandpiper that meets minimum weight requirements (~80 g) is fitted with a Lotek PinPoint ARGOS satellite tag weighing 4 g. Each tag is affixed to the bird using using glue to adhere to the back feathers; the tag drops off when the bird molts these feathers in fall. These tags have a dedicated battery that provides ~75 location fixes that are programmed to a specific schedule. Our plan is to test two tag schedules in year one and adjust as needed in year two. The first schedule will be used for the majority of tagged birds and is intended to focus on local movements at Lake Red Rock. We anticipate that residency time is approximately 5-6 days based on other studies, so the tags will be programmed to record ~15 locations per day for 5 days. The second schedule will be used with approximately five birds and is designed to collect data on fall migration patterns beyond the study site. For these birds we will program the tags to collect fewer locations per day until the battery is depleted, giving a better picture of where the birds go once they leave Iowa.

The tracking devices

We are using two tag types to track Pectoral Sandpipers, each with different capabilities that are geared to answer specific questions. The first tag, which is used on most of our birds, is the Lotek PinPoint GPS ARGOS tag weighing 4 grams. We're using this tag to collect frequent (~hourly) locations of sandpipers at Red Rock to better understand how they use this site during migration. It has a dedicated battery and no solar panel meaning we'll get a maximum of ~75 locations before the tag bettery dies. The second tag is the LOTEK Sunbird Solar ARGOS tag weighing ~2 grams. This tag does not collect GPS locations, meaning the fix accuracy is lower than with the PinPoint tags. However, this tag is rechargeable and lasts much longer, allowing us to track movements at and away from Red Rock Lake. We're hoping that by using both tags we can better understand Pectoral Sandpiper movements and local and hemisphere scales. All work is approved by the ISU Institutional Animal Care and Use Committee (IACUC protocol #22-150) and federal and state banding permits held by SJD.




LOTEK Sunbird Solar ARGOS tag
Pectoral Sandpiper with a PinPoint tag. Photograph by Stephen J. Dinsmore.
Pectoral Sandpiper with a Sunbird tag. Photograph by Stephen J. Dinsmore.


Here are the latest tracks for the birds we've tagged so far. Please recall that these locations are unfiltered and some points are clearly incorrect and will be edited out at a later time. This is a cost of providing the data in real time. Enjoy!

Bird 252421 

Bird 252422 Tracked to the Dominican Republic

Bird 252423 

Bird 252424 Tracked to Colombia

Bird 252425 Tag was a partial failure

Bird 252426 Tracked to Colombia

Bird 252427 Tracked to Venezuela

Bird 252428 

Bird 252429 

Bird 252430 

Bird 252431 Tracked to Colombia

Bird 252432

Bird 252433

Bird 252434 

Bird 252435 

Bird 252436 

Bird 252437 Tracked to Colombia

Bird 252438 

Bird 252439 Tracked to Venezuela

Bird 252440 

Bird 252441 

Bird 252442 

Bird 252443 

Bird 252444 

Bird 252446 

Bird 253348 Bird has moved north to Saylorville Lake

Bird 253349 Currently in Puerto Rico

Bird 253350 Currently in Venezuela

Bird 253351 Currently in Venezuela

**Tracks updated on 10 November 2023. Note that only Birds 253348 through 253351 are still actively transmitting data.



We thank the U.S. Army Corps of Engineers and the Sustainable Rivers Program for funding this work. Thanks are due to the many individuals who have helped with this work, especially Todd Gosselink, Kevin Murphy, Rachel Ruden, and Perry Thostenson.

Literature Cited

Calomeni, A. J., C. Theiling, and B. C. Suedel. 2022. Planning and Implementation of Environmental Pool Management at Lake Red Rock, Des Moines River, Iowa. EWN Technical Notes Collection. ERDC/TN EWN-22-6. Vicksburg, MS. US Army Engineer Research and Development Table.

Farmer, A., R. T. Holmes, and F. A. Pitelka. 2020. Pectoral Sandpiper (Calidris melanotos), version 1.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.

Murphy, K. T., and S. J. Dinsmore. 2014. Stopover dynamics of fall migrant Pectoral Sandpipers in Iowa. Wader Study Group Bulletin 121:186-192.

TNC (The Nature Conservancy). 2020. Sustainable Rivers Program: Modernizing Water Infrastructure to Maximize Benefits. Land and Water Stories.


For more information or comments please email Dr. Stephen J. Dinsmore, Iowa State University ( ).


Preferred citation for this page:

Dinsmore, S. J. 2023. Iowa Pectoral Sandpiper Stopover Study.…