Predators In Command During Pandemic Plover Season (Shorebird Wrap-up 2020) by Jamie Bogart, Lloyd Center Research Associate
As of the June update, we reported that the “parking lot pair” of Bakers Beach had its nest exclosed again this season and as expected, produced four chicks. This however, is one of those pairs where the challenges start when the chicks emerge. Two seasons ago, the brood spent extensive time in the private parking lot, during which time one hatchling found the bottom of a storm drain, and another, the fathoms of a beach bucket partially filled with water. Both chicks plus another, miraculously fledged. Last season one might say the parents learned their lesson, and took the brood west toward the town beach, where optimum dune cover and foraging habitat existed.
This season a similar scenario unfolded, only this time the chicks headed east, and spent the entire hatchling phase on Horseneck Beach. In these last two seasons only two of four chicks survived, which, while considered a success, shows that predators are still a force on the beach. The three most common predators of crow, fox, and coyote, continue to target Piping Plovers. This season, one of the eggs hatched a day late and although the birds become difficult to tell apart as they mature, it’s possible this weaker bird survived to fledge.
Quietly, this pair has become iconic. The sandy parking lot of a privately-owned beach is a relatively unique habitat situation that will only increase in importance as shoreline is lost to climate change. On a conservation landscape where vast closures of beaches have always been the norm, the landowners have remained open for business in full every year, while sacrificing lot space to benefit the birds, vigorously protecting them and ensuring it’s the one pair along the entire barrier beach where an exclosure is always used, and almost never fails. The pair is sure to entertain us well into the future, and be a critical pair in the productivity equation. West Island has become a tale of two sides, the Town of Fairhaven portion with the public beach and vast interdune flats, and the Department of Conservation and Recreation (DCR) portion with the inlet to the lagoon, dividing a mostly extremely narrow barrier beach other than small sand spit habitats and a blowout area sometimes used for camping. Although the crowds are highest at the public beach, the entire island is bustling with human activity of various kinds from swimmers, boaters, clammers, dog walkers, kite surfers, fishermen, drone users, and others, not to mention uses that may occur during the night hours during summer, hence, protecting the birds is always a meticulous process. With the increase in abundance to a record twelve pairs last season, and this season a still formidable eight pairs returning, it’s fitting that the Lloyd Center, in addition to the Town of Fairhaven contract, was awarded a subcontract with DCR to assist with the birds on the state portion of the island.
There were four nesting pairs on town property, five on DCR (including one pair that nested in both sections), making pairs widely distributed around the island and a convenient buffet for predators. Sure enough, the predation that started in June continued. Nest loss this year (11) was comparable to 2019 (10) and other than subtle differences, evenly distributed across the two properties. Last year, nests lost on town (6) vs DCR (4) were slightly higher while this season this trend was reversed with nest loss on DCR (6) higher than the town beach (5). However, because pairs may renest and the critical statistic is which pairs produce fledges, the property with losing the most nests had the higher productivity. For the first time success will be higher on DCR beach (1-1.6) with 5-8 fledges produced vs the town beach (.75) which declined considerably this season and produced only three fledges from one successful pair. However, the island as a whole will have productivity ranging between 1-1.3, not far different from 1.4 seen last season, which while not the 2.5 observed in 2018, will maintain population stability.
While some barrier beach erosion has caused all nesting to be on spits or in the low dune habitat on the town property, sand has accreted (increased) on the DCR side, where pair abundance increased starting last season and continued this year. With the first nesting attempt being critical on a site with small nesting areas from which pairs may depart early before renesting, it was encouraging to see a pair produce young after four tries. Within the past week, three chicks hatched from a pair that initially nested on the town beach, but then had three nests on the new habitat before finally producing young. The overall trend on the island is higher success on later attempts, and an additional nest near the channel produced hatchlings on its second attempt, the first nest lost from back in a blowout area, the renest succeeding on the bay side of the dune, despite frequent human and predator passage. The two remaining chicks should fledge next week.
Back on the town beach we know a predator exclosure saved one nest and we can report that three chicks fledged. Although this was the only successful pair, it’s both a highly educational pair that will now likely return to the town spit to nest next season, and it reaffirmed the usefulness of exclosures on West Island Town Beach, the one site in the region where exclosures can be used freely. That said, they are still used cautiously and not always with success. An additional pair made three nest attempts, one in the low dune and two down on the barrier beach (a less common nesting habitat on the town beach which has shown some erosion in recent years). Knowing the high predation rate and seeing signs of animals such as crow and coyote closing in, the decision was made to exclose, even though the pair was already skittish and the nest close to the fence border. While the exclosure was accepted, sadly (but not unexpectedly) the pair abandoned soon after the first major heatwave brought crowds to the beach. We’ll never know if the eggs would have hatched if left alone, but took solace that something was done to protect a nest all but sure to have been predated. With no abandonments the prior season of the two exclosures, the statistics still favor their use, and exclosed nests will continue to appear.
Regarding human use, all attention was on coronavirus responses at beaches to reduce crowding, which has lasted the season. West Island instituted a restriction allowing town residents only to access the beach once the beach opened for summer. Although the predators again dictated the outcome as often occurs (a factor independent of how crowded the beach gets), less human use down the stretch surely benefits the birds. Incidents are rare and although we’d much rather not see people excluded from any beach, one might consider peace for the birds a positive side of the coronavirus response.
The spring closures of beaches that had impacts on Plover beaches across the entire range of the species this season reached Buzzards Bay in the form of a nest found in the City of New Bedford, on the south end peninsula at “East Beach”. The Lloyd Center contributed to monitoring of the site after the nest was confirmed. The nest was located by a beach walker in June, and was deemed a renest likely from West Island. Late discovery of this nest prevented adequate protection and the nest was abandoned, the pair determined to have then crossed the harbor to Winsegansett Heights in Fairhaven, where it was briefly territorial but never renested. Although it was only a matter of time before New Bedford beaches supported a Plover pair, coronavirus closures early on were surely a factor for a beach usually more crowded with people. While the nest didn’t succeed, the city of New Bedford made a fine effort to protect the birds according to regulatory guidelines with no time to spare, and the fact that the pair managed three eggs before any protection occurred is impressive. Most importantly, New Bedford is now officially on the map of Piping Plover habitat in Bristol County, with East Beach sure to be closely monitored next year when the birds return.
Tune in next spring for shorebird kickoff 2021 on a beach near you!