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Least Terns Strike First, and Often, at Horseneck State Beach

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As the shorebird season reaches its midpoint, the first Plover chicks have appeared at the Horseneck Beach State Reservation within the past week and nesting is well underway at the  other Department of Conservation and Recreation (DCR) beaches. This season, the compelling story thus far at Horseneck involves the Least Terns, which nested on the Horseneck main  beach before the Plovers for the first time. In fact, due in part to a cool spring and a significant storm that coincided with a high tide and some reshaped beaches, the Plover season was slow to evolve. It seems that south facing beaches, less sheltered from the prevailing southwesterly winds, may delay nesting during stormy springs such as this one.

The Least Terns were right on schedule, and arrived to an excessively rocky east refuge area at Horseneck where most of the colony has formed. A main beach that offered high-quality habitat with a lightly-cobbled berm, and new sand surrounding the headquarters created by a dune restoration project, were perfect alternatives right next door.  To date, while only three pairs of terns have nested thus far on the main beach, this is where the first tern nests appeared. Currently a smaller colony exists at Horseneck, but most nests are now in public areas. The colony that existed in the traditional refuge was quickly pursued by coyotes, sending these terns to the main beach and dune restoration areas, where new scrapes appear by the day. In the restoration area alone, approximately fifteen pairs exist, most of which are clustered near the concessions area! A nest was also confirmed in the west dunes for the first time in years. A slightly reduced colony won’t seem so to beachgoers, once the young become visible and mobile, and the already moody adult terns increase their angry pursuit of intruders! At Demarest Lloyd State Park, a small colony has also formed, although success has been low there in recent years.

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For the Plovers, a preliminary estimate of total nesting pairs is nine at Horseneck, six at Demarest Lloyd, and three between West Island and Winsegansett Heights. Nesting success, assuming all currently active nests hatch, is looking good. One early nest was lost at each site due to predator influences, including an abandonment caused by White-tailed Deer in the Horseneck restoration area! American Crow are suspected to have predated a nest each at Demarest Lloyd and West Island, but predator control efforts have quieted the crow onslaught. More recently, a high tide event coinciding with stormy weather overwashed a nest each at Demarest Lloyd and West Island. Both pairs have since resumed scraping with hopefully another clutch of eggs soon to come. Currently two pairs that probably first showed interest in West Island are present at Winsegansett Heights, confirming a long season ahead for Plover work! An exclosed nest each at Demarest Lloyd and Horseneck exists, with the latter just hatching, the former going strong. Success of a small number of exclosed nests relative to predator influences has gone well.

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The location of Plover nests is always intriguing. At Horseneck, there are two pairs in restoration areas and five in the west dunes where density is again high. The west dune pairs shifted closer to the main beach due to a steeper west dune toward Bakers Beach, caused by an April stormy high tide. Although pairs might have missed the boat this year for main beach nesting due to beach crowds and beach preparation, two additional pairs are still scraping in various locations including areas in the dunes. One of these scraped in probably every crack near the headquarters early on! With many hatches soon to come, including two nests near buildings that will surely hatch to coincide with the first huge beach crowds, many stories are yet to unfold.

At Demarest Lloyd, pairs are again distributed along the periphery of the sand spit, likely in response to early stress from crow that predated the one interior spit nest thus far. Hatchlings are due any day at Demarest Lloyd. On West Island, pairs nested along the main berm and in a blowout area, both on the town beach, and includes a banded Plover, apparently tagged in Massachusetts within the past two seasons! The pair with the banded bird has reappeared, scraping closer to the town lot. Although scraping has occurred on DCR property at West Island, most habitat by far still exists on the town beach. A long way to go there … but hope is high for nesting success this season on West Island!

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Let’s not forget the Ospreys, which actually arrived to our sites later than the Plovers this season. At this time we are happy to report three confirmed nesting pairs, one on Little River, and two on the Slocum River at the platforms across the estuary along Demarest Lloyd, viewable from the Lloyd Center Osprey Room Observatory. At Little River, unfortunately, an undetermined predator (likely Great Horned Owl, a known Osprey nest predator) has finally caught on after some years of consecutive fledging success at the site. The Osprey pair remains so we’re hopeful for a re-nest soon. The exciting news is that after a failed season at our traditional platform last year, we can report that young Ospreys are currently in both nesting platforms! Two newly born chicks occupy the traditional platform, while the platform near Giles Creek has three chicks, for a total of five Osprey chicks in our “backyard”. Next month we hope to band some or all of these, and track them for years to come.

Tune in later on for the season summary, to include a result of the Diamondback Terrapin season which is just getting underway!