Lost and Found: Tracking an American Oystercatcher with GPS/GSM Technology

The tiny backpack you see on this American Oystercatcher “N94” is a solar-powered GPS/GSM transmitter. Thanks to this technology, applied by a trained biologist, we were able to find N94 after she went off grid for three months. The transmitters also help researchers identify important habitat, understand migration patterns, and coordinate conservation efforts with partners across the hemisphere.

N94 was one of five original birds in Connecticut to be fitted with a GPS/GSM transmitter. Last year, she nested at Sandy Point beach in West Haven. At the end of the summer, she staged for migration at Milford Point, and we tracked her coordinates to the marshes just north of Atlantic City, New Jersey. Then... silence. After three long months she pinged again in Virginia.  

At the beginning of the 2026 nesting season, she traveled northbound back to Sandy Point where she rejoined her mate, N95. The pair spent the spring incubating their eggs and successfully fledged two chicks.

Field staff member Becca Mulligan monitored N94 and N95 throughout the summer and observed that “they seemed to be the most vigilant pair at Sandy Point and would run the chicks back into the vegetation well before anyone got close. I also noticed that one chick would hang around N95 and bother him all the time, chirping and chasing him even after fledging."

When birds feel stressed, they display behaviors of vigilance like scanning the beach for threats and moving their chicks away from perceived threats. Even a calm beachgoer walking too close can lead to this behavior.

Happily, this American Oystercatcher family made it safely through the season. In late July, staff observed N94, N95, and their fledglings mixed in with a larger group of oystercatchers that were "staging" on the sandspit before beginning their southbound migration. 

The latest pings shows N94 in the marshes just north of Atlantic City, New Jersey.

Thanks to GPS/GSM backpacks, researchers are learning more about where American Oystercatchers breed and overwinter. As you can see from this map, N94 nested at Sandy Point beach in West Haven. Her movements reflect the territorial nature of American Oystercatchers - she stuck close to her nesting site and only left to go forage.  

A different bird, N93, did not mate or nest this season, and his map shows a wide range of movements. 

The data shows that a non-breeding bird will use a significantly larger area when they are not defending their territory and raising young. 

N93 was still staging for migration at Milford Point as of late September. Last year, he spent the non-breeding season on the west coast of Florida, and we are eager to see if he does so again.

N94's journey is just one example of what tracking technology can reveal. Each new location ping helps researchers better understand how American Oystercatchers use habitat throughout the year, information that is critical for protecting the beaches, marshes, and coastlines these birds depend on across the hemisphere.