Summer by the Numbers 2026

Island Sentinel Program

For over a decade, the Island Sentinel Program has been one of the Conservancy’s longest-running youth stewardship programs, connecting local knowledge with hands-on conservation work and giving youth a role in observing and caring for our islands natural environments. Over the years, Sentinels have documented everything from wildlife and shoreline conditions to marine debris and seasonal ecological change across the island’s monitoring sites. In 2025, a significant effort went into reviewing that historical dataset, and one thing stood out clearly- over 70% of everything ever recorded was bird-related. 

That finding shaped a deliberate shift for the 2026 season. Rather than continuing to track a wide range of categories, this year’s approach leaned into what the data showed was already the program’s strength: bird  observations. Sentinels were assigned specific sites to visit consistently, given standardized routes, and asked to record GPS coordinates at the start and end of each visit. By focusing more narrowly on birds and standardizing how that data gets collected, the program is aiming for the ability to compare biodiversity across sites, track seasonal patterns in which species are using different parts of the island, spot ecological shifts and notable events as they happen, and build a comparable, long-term record. Digital data collection and direct integration with the islands iNaturalist project reinforce that goal, giving every observation a timestamp, GPS location, and photo verification. None of this changes what the program has always been at heart, an approachable, hands-on way for the youth to get outside and pay attention to the island around them. 

By the Numbers

This season, 3 Sentinels logged 86 visits across all 10 of the program’s official monitoring sites between June and mid-August, a strong first season for the program’s more structured, site-based approach.

Those 86 visits added up to an estimated 1,266 individual birds observed, spanning 42 unique species across the island. That’s an impressive amount of data for one season, and it’s exactly the kind of consistent, wide-ranging coverage the program’s 2026 changes were designed to produce.

The program’s 10 monitoring sites, Silver Eel Cove, Race Rock Point, South Beach, Hay Harbor, Dock Beach, Isabella Beach, Middle Farms, Chocomount Beach, Fishers Island Club Beach, and East Harbor, represent a mix of beaches, harbors, shoreline areas, and pond environments established over the program’s history to give a broad, island-wide picture of wildlife activity. That said, coverage wasn’t even across every site. A few sites, like South Beach and Silver Eel Cove, saw far more consistent visits than others, while a couple of the more historically included sites saw only light coverage this season. As a pilot year for this more structured approach, that’s exactly the kind of information we wanted this season to surface. Going forward, we’ll be looking closely at which sites are producing consistent, useful data and which ones may need adjusting, whether that means expanding effort at high-value sites, reworking how a lower-traffic site gets monitored, or reconsidering whether every historical site still makes sense to keep in the rotation. The goal isn’t to lock in exactly 10 sites forever, it’s to make sure wherever Sentinels are spending their time is actually building toward that long-term, comparable record the program is working to establish.

Common Tern, Common Eider, and Barn Swallow make up the largest share of individual birds recorded this season, and there’s an ecological reason behind that. All three are highly social or colonial species, meaning they naturally gather in large groups rather than being spread out individually across the landscape. Common Terns feed and roost in flocks, often diving together on schools of baitfish, which is exactly what drove two of this season’s biggest single counts, over 100 individuals recorded feeding together on more than one occasion. Barn Swallows behave similarly around structures like docks, where dozens can roost or forage together at once, which is why a single site visit could turn up 50 or more in one sighting. Common Eiders, meanwhile, gather in rafts on open water, especially outside of the breeding season, so a handful of sightings can easily account for a large share of the season’s total. These numbers aren’t showing that our island has an unusually dense population of these three species compared to everything else, they’re showing how flocking behavior concentrates individual counts around a small number of highly social species. That’s a normal and expected pattern in bird survey data, and it’s actually a good sign.Iit means Sentinels were in the right place at the right time to catch these species doing what they naturally do.

The rest of the list tells us about the range of habitats Sentinels are covering. Double-crested Cormorant, Osprey, and Herring Gull round out the next tier, all common, easily identified species that use the island’s beaches, open water, and rocky shorelines throughout the summer. Osprey in particular is a great indicator species to see well-represented, since its presence reflects a healthy local fish population and clean coastal water. Further down the list, species like Least Tern, Great Black-backed Gull, Tree Swallow, Red-winged Blackbird, Song Sparrow, and Spotted Sandpiper reflect the mix of shoreline, marsh, and upland habitat types the program’s 10 monitoring sites collectively cover. Having this many distinct species show up meaningfully across just one season, rather than the list being dominated entirely by two or three species, is a strong early sign that the more structured 2026 monitoring approach is capturing a slice of the island’s bird life, not just whatever happened to be easiest to spot.