Black Skimmer Tracking Shows A Shift for Fish

This article was co-written with Brien Weiner of the South Shore Audubon Society, serving the southern half of Nassau County on Long Island, New York.

When researchers fitted 20 Black Skimmers at Lido Beach with GPS transmitters this summer, they expected to learn more about where the birds foraged in the back bays.

They uncovered a much bigger story about food scarcity. The tracking data revealed unexpected trips spanning as much as 110 kilometers (68 miles) to New Jersey’s Gateway National Recreation Area. As researchers pieced the story together, one clear driver emerged: the availability of Atlantic menhaden.

One of the most adventurous tagged Black Skimmers was Michelle (Obama), a seven-year-old Black Skimmer that hatched at Lido Beach in 2019. 

While many skimmers stayed closer to Long Island, Michelle became the only tracked bird to cross Long Island Sound, making trips to Bridgeport and New Haven, Connecticut. She also frequently foraged east of the colony near Babylon and north toward the Bronx.

Ronald (Reagan), meanwhile, headed in a different direction. The male skimmer regularly made nighttime trips to Sandy Hook and Gateway National Recreation Area in New Jersey. Closer to home, he spent much of his time in marshes west of the colony in Bay Park, which is also the site of a wastewater treatment plant undergoing major upgrades to clean up the back bays.

The group of tracked birds revealed interesting patterns. Males generally foraged west of the colony, while females tended to head east. Many of the longest trips occurred under the cover of darkness, between 10 p.m. and 3 a.m., suggesting that skimmers were willing to travel remarkable distances in search of food.

The likely reason was swimming beneath the surface.

Atlantic menhaden are a small forage fish that play an outsized role in coastal ecosystems and are a critical food source for Black Skimmers. Previously collected data in 2024 showed that menhaden made up 41 percent of the diet of Black Skimmer chicks at Lido Beach. During the early part of the breeding season, however, menhaden appeared to be scarce in local waters.

When menhaden arrived between July 31 and August 8, the birds quickly shifted their behavior and once again concentrated their foraging efforts in the back bays closer to home.

In November, The Atlantic States Marine Fisheries Commission, the regulatory body in charge of setting menhaden fishing limits for New York and other coastal states, will vote on an addendum which could increase menhaden protections for the next several years. Protecting our fish is important to making sure our migrating birds have enough to eat along their migration routes, and black skimmers are no different. Menhaden are an important food for many birds and fish along the Atlantic, and these protections would help not just Black Skimmers, but other coastal birds like osprey and bald eagles.

This summer's tracking project was designed to learn more about what makes Lido Beach a successful nesting ground relative to other locations on the Atlantic flyway. 

Michelle, Ronald, and the eighteen other birds quickly revealed that the health of Long Island's largest Black Skimmer colony is linked to the availability of a small silver fish hundreds of feet below their flight path.