Sharing the shorelines, protecting piping plovers at Sleeping Bear
Originally published by the Friends of Sleeping Bear Dunes 9-26-19.
photo credit: Friends of Sleeping Bear Dunes
It was 1993 when two piping plover pairs were sighted. Both were on North Manitou Island, one pair at Dimmick’s Point and another at Donner’s Point. Two years later, the first pair arrived on the mainland at Platte Point.
Steve Yancho, retired Chief of Natural Resources at Sleeping Bear National Lakeshore remembers hauling in equipment to North Manitou in 1988-1990 for predation control to protect the plover. “Funding was always a challenge. We never knew from year-to-year where the funds would come from, and we always had to search for funding sources. I was proud of keeping the plover program going.”
The population had dropped to a dangerous low of twelve pairs by 1985 when it was federally listed as an endangered species.
By 2017, the park’s plover population grew to the highest in the Great Lakes region according to Erica Adams, field lead for the program. “Forty-one pairs nested in the park that year, with about one-half of the pairs on North Manitou Island.” Dimmick’s Point on North Manitou is closed to the public every year from April through August to reduce human contact with the nesting plovers.
There were eight plover nesting zones in 2019—five on the mainland, two on North Manitou and one on South Manitou. Each year the nest sites are roped-off with signage, and all nests are protected from predators with ‘exclosures’ that resemble a wire cage with netting.
The Great Lakes piping plover is a co-parenting species with one parent always incubating its ground nest in fragile, open beach habitat. Plovers have faced a loss of quality nesting area and increasing risks from predators—merlins, crows, gulls, raccoons—making it difficult to safely incubate, feed, and protect their chicks.
Over the years the park has tested-out different styles and sizes of exclosures to protect the nests while allowing the parent plovers to easily enter and exit when incubating. A mid-sized wire exclosure with netting covering the top is used to protect all plover nests on both the mainland and North and South Manitou Islands.
Alice VanZoeren, researcher with the University of Minnesota who has worked on the plover program since 2004, explains: “Success with the exclosures brought the plovers’ hatch rate from a thirty percent hatch rate to a ninety percent hatch rate. It’s the most effective exclosure, and it’s very rare for a nesting pair to reject it.”
“Piping plover are very tied to sites where they successfully nested before, and not necessarily to the site where they were hatched. They’ll often return five to seven years to the successful nesting site,” said VanZoeren, who does almost all of the adult plover banding for Sleeping Bear’s population.
Rising waters are now an emerging threat, limiting viable habitat. The loss of shoreline from rising water levels in Lake Michigan presented a challenge in the 2019 nesting season. “High water levels push piping plovers into smaller levels of habitat, and this raises the risk of predators because it means the plovers will be nesting closer to the tree line giving predators an advantage,” explained VanZoeren. “And nest wash-outs are a threat.”
Thirty-two pairs nested in the summer of 2019, down from the high point of forty-one pairs in 2017. But the higher water levels can be cyclical and reverse once again, and receding waters can reveal enhanced habitat for the plover.
Visitors ask the plover beach monitors how the shorebirds are doing and might, from a safe distance, catch a glimpse of one scurrying across the beach. This is a testimony to the efforts over the past twenty-five years and longer—the work and dedication of many people, partners, and organizations with integral roles in the continuing growth and survival of this iconic species.
The Friends of Sleeping Bear have provided tents and sleeping bags for program staff who spend long stretches of days and nights conducting research and monitoring nests during spring and summer plover nesting season.
Historically, piping plovers had thrived in their nesting grounds on the Great Lakes shorelines which was once home to about 800 nesting pairs. For more information on the piping plover protection program and how you can help: https://www.greatlakespipingplover.org