Species Spotlight: the rufa red knot

By Susan Sorg, nature writer

Using its internal compass and the moon, stars, and sun, the rufa red knot makes one of the longest migrations on Earth, nearly a 20,000 mile round-trip flight from the southernmost tip of South America to its Arctic nesting grounds. Along the way, the red knot may face multiple risks—peregrine falcons, coastal development, and hurricanes. But since the overfishing of horseshoe crab in the 1990s, which caused a decline of the red knots’ critical food, the population has plummeted.

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The migration route of red knots from Tierra del Fuego in South America to their breeding grounds in Canada. Graphic: Guilbert Gates.

Rufa red knot (Calidris canutus rufa) is a large sandpiper weighing an average 4.8 ounces with a 20-inch wingspan, about the size of an American robin. There are three subspecies in North America and six species worldwide; rufa red knot is the eastern North American species. Their characteristic rusty ‘rufous’ plumage is the perfect camouflage in the Arctic breeding grounds to blend with wild grasses and wildflowers. In the fall they molt to a bland grey and white coloring for protection on the beaches of their South American wintering grounds.

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Rufa red knot. Photo: Dick Daniels.

Red knots and horseshoe crabs share a long history of interconnection, a delicate synchronicity of nature—the spawning of millions of horseshoe crab eggs in the Delaware Bay each spring is precisely timed with the red knots’ arrival in May. On its northward migration, the red knots’ key stopover is Delaware Bay—roughly half-way from their wintering grounds, Tierra del Fuego in Argentina to the Arctic nesting grounds.

Nothing in nature exists alone. The fragile relationship of the rufa red knot and the ancient horseshoe crab is one of nature’s many delicate partnerships. With the decline of horseshoe crabs came the quick decline of the red knot—both populations have dropped about 75% since the 1990s. The rufa red knot is one of the most rapid and serious shorebird declines.

At Delaware Bay, the red knot must quickly refuel for energy to successfully complete the last leg of the long journey to the Arctic and breed. This event has been evolutionarily perfected over millions of years. When the red knots arrive, they are exhausted and starved after four or more days flying nonstop from South America and must refuel with horseshoe crab eggs which provide easily digested protein. They can double their weight during this 12-14 day stopover, and this body fat is necessary to reach the Arctic and successfully breed.

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The red knot survival is profoundly linked to the crabs, a species older than dinosaurs. Photo: Jan Van De Kam.

Almost the entire eastern North American population of red knots will congregate in Delaware Bay during spring migration. “Historically, more than 100,000 red knots stopped at Delaware Bay each spring. By 2004, this number had dropped to little more than 13,000” (American Bird Conservancy, February 2015). Although the horseshoe crab population is reported to have stabilized since improved protections restrict overfishing, concerns remain as to whether the crab population will recover fast enough for the red knot. Volunteers protect the Delaware Bay during spawning season, and horseshoe crabs used in medical research are also returned alive back to the ocean.

Climate change has now emerged as a greater threat. In 2014, the rufa red knot was listed as Threatened under the Endangered Species Act and is the “first bird listed explicitly because its existence is imperiled by global warming” (“Red Knots Are Battling Climate Change—On Both Ends of the Earth,” Deborah Cramer, Audubon Magazine; May/June 2016). Rising sea levels and storms may engulf the red knots’ coastal habitat, and erratic temperatures can cause timing ‘mismatches’ (asynchronies) in nesting. Chicks need to hatch simultaneously with the insects’ hatching to guarantee abundant food.

Coastal habitat conservation efforts in Michigan which benefit the endangered piping plover, pitcher’s thistle, Houghton’s goldenrod, and Lake Huron tansy also benefit the rufa red knot, as the species utilize similar habitat. Red knots are an uncommon migrant in Michigan and never abundant here, but could be spotted along Great Lakes shorelines heading north in late May or again in late July through September on their southern migration. In Michigan’s Upper Peninsula it is possible to spot a red knot at MNA’s Lake Superior Nature Sanctuary or Whitefish Point, and in the Lower Peninsula, Point Mouillee State Game Area, Tawas Point State Park, and Lake Erie Metropark at the southeastern point of the state.

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Climate change may extensively reduce the red knot’s breeding and roosting habitats. Photo: Greg Breese.

Half the species of shorebirds in the United States and Canada are either endangered or of special concern, according to the U.S. and Canadian Shorebird Conservation Plans. The Western Hemisphere Shorebird Reserve Network has adopted a conservation strategy that is currently focusing on protecting 97 critical sites internationally, which includes Delaware Bay. For more information visit http://www.whsrn.org/western-hemisphere-shorebird-reserve-network and the USFWS at http://www.fws.gov/northeast/redknot/ to learn more.

Lake Erie Waves, Great Lakes Forests, and Mudpuppies: this week in environmental news

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Turbulent waves in Lake Erie. Photo: Dave Sandford.

This Is What A Great Lake Looks Like After All The Vacationers Are Gone (Buzzfeed): Photographer Dave Sanford spent time on Lake Erie shooting the Great Lake’s turbulent fall season. From mid-October to mid-November, the longtime professional sports photographer traveled each week to Port Stanley, Ontario, on the edge of Lake Erie to spend hours taking photos. His goal was to capture the exact moment when lake waves driven by gusting winds collide with a rebound wave that’s created when the water hits a pier and collection of boulders on the shore. People are blown away that these are from a lake, and not an ocean due to the size and force.

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Crayfish in Burt Lake are thought to be on the decline. Image: Greg Schechter, Flickr.

Pharmaceutical pollution takes toll on crayfish and other species (Great Lakes Echo): Drugs seeping into groundwater threaten crayfish and have a domino effect of environmental impacts that harm fish and other species, according to new research. Pharmaceutical pollution happens when medicines are improperly disposed or flushed into septic tanks and sewers as the body eliminates them. Treatment can’t filter them so they make their way into lakes and streams. Crayfish are a keystone species, one that many others species depend upon. If they died, so would trout and bass. That would lead to algae overgrowth and in turn, insects and invertebrates would die when decaying algae used up all the oxygen. At this point there are not solutions for removing pharmaceuticals once they are in lakes and streams, so this is a prevention issue. We need to keep it out of the waterways, improving septic and sewer systems to filter pharmaceutical pollution is a critical need.

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Red pine forest in West Michigan. Image: Marie Orttenburger.

Researchers look to brace Great Lakes forests for climate change (Great Lakes Echo): Great Lakes forests will get warmer and suffer more frequent short-term droughts, scientists say. The stakes are high. Forests are staple ecosystems in the region. Many wildlife and plant species depend on forest stability. Plus, forests are a part of the regional culture. The approaches to climate change adaptation for trees are as diverse as the tree species.

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Underwater shot of a mudpuppy at Wolf Lake. Image: Alicia Beattie.

Secretive amphibian can provide pollution clues (Great Lakes Echo): The mudpuppy is a fully-aquatic salamander thought to be on the decline–though the extent of that decline is unknown. The foot-long amphibians are classified a “threatened species” in the state of Illinois and considered a concern throughout the Great Lakes region. Destruction and degradation of habitat, along with invasive species, are spelling doom for mudpuppies. Mudpuppies are also very sensitive to pollution. That characteristic could make them especially important to researchers. Population statistics and tissue samples could clue scientists in on the effects pollution and habitat degradation are having on those environments.

Volunteers Help MNA Complete Rare Orchid Survey

By Katherine Hollins, MNA Regional Stewardship Organizer – Eastern Lower Peninsula

A PFO peeks out behind the tall grasses. Photo by Dan Sparks-Jackson

A PFO peeks out behind the tall grasses. Photo by Dan Sparks-Jackson

MNA is fortunate to protect one of the top-ranked lakeplain wet-prairies in the state. This globally imperiled habitat is home to a beautiful diversity of plants, perhaps one of the most showy being the eastern prairie fringed orchid (PFO). MNA protects one of the largest populations of PFO and one of the few populations in the world that is considered long-term viable.

This beautiful, sweet-smelling orchid is a mysterious plant. It was once common in the state, but its population has declined to the point that it is now considered endangered by the state of Michigan and threatened by the federal government. This population decline is primarily due to habitat destruction. Many of the rich prairie soils were plowed into farm fields, and other areas were ditched or diked, altering the hydrology of the habitat that is so important to the plant.  However, while we tend think of it as requiring extremely high quality habitats to survive, specimens have been found in roadside ditches and along the edges of mowed fields.

Volunteers gather for orientation at the beginning of the day. Photo by Dan Sparks-Jackson

Volunteers gather for orientation at the beginning of the day. Photo by Dan Sparks-Jackson

Historically, fluctuating lake levels helped support PFO habitat. High water pushes the orchid population inland, and prevents shrubs and trees from encroaching into the sunny prairie. When lake levels lower again, the orchid population moves back shoreward. Each year some plants are lost to too much or too little water and new ones are recruited where new suitable habitat is created. With land alterations, however, this ability to shift inland and shoreward according to the lake levels has been hindered.

Seasonal drought, lake level changes, and other factors influence the number of annually surviving plants, as well as the number of blooming plants. Individual PFO plants may not flower every year or may even go dormant when conditions are not favorable. In their PFO paper, Mike Penskar and Phyllis Higman say, “… the species is notorious for having large fluctuations in the number of flowering individuals from year to year.” Continue reading