Mention of Midway brings to mind myriads of birds. But, there's more to Midway... Known as Pihemanu (“loud din of birds” in Hawaiian), Midway Atoll National Wildlife Refuge is a bustling (and noisy) spectacle of seabird life. Midway holds the title as the world’s largest albatross colony, with more than 1.5 million albatross packed on its three tiny islands. Midway’s albatross populations are globally significant as well: nearly 70% of the world’s Laysan Albatrosses and nearly one third of the world’s Black-footed Albatrosses nest on the atoll each year. For 9 months of the year, albatross dominate and manage to occupy ever bit of inhabitable space. But, both above and below, bird life abounds. Bonin Petrels and Wedge-tailed Shearwaters / ʻUaʻu Kani build extensive, maze-like burrows underground while Red-footed Boobies / ‘A and Great Frigatebirds / ‘Iwa nest overhead in trees and shrubs. In addition to albatross, more than 20 other bird species use Midway for resting and nesting, including two federally-listed species: the critically endangered Short-tailed Albatross and Laysan Duck. Currently surviving in only three populations in the Northwestern Hawaiian Islands, Laysan Ducks have been pushed to the point of extinction several times, but have miraculously survived and recovered thanks to critical efforts by scientists and conservationists. In 2004-2005, 42 ducks were translocated to Midway to serve as a back-up population. Since then, Midway’s Laysan Duck population has soared to several hundred. Photo credits: Dan Clark/USFWS, Rob Shallenberger, Wieteke Holthuijzen, Megan Dalton. Although birds inhabited Midway for centuries in isolation, birds have (more recently) shared the atoll with humans, beginning with the Commercial Pacific Cable Company operation in 1903. Unfortunately, sharing space on a small, 2.4 square mile island system has not always been a harmonious coexistence, as seen through historical fluctuations of bird populations and gradual recovery. Sometimes birds were actively killed or nesting areas were destroyed to exclude them from areas important to residents, commercial enterprises, or military purposes. Eggs, chicks, and even adults were vulnerable to predation by rats, cats, and dogs accidentally or intentionally introduced to the atoll. Since 1986, when Midway was designated as an overlay Refuge, the atoll entered a new era of restoration and revitalization. Now, the migrations and breeding cycles of birds, seals, turtles, and flowering sequence of the islands’ plant life define the seasons on Midway. But, to only meet Midway’s wildlife would ignore an equally interesting and biodiverse segment of the onshore ecosystem, a unique assemblage of biota brought to the atoll by wind and waves (and later, people). More than 160 plant species occur on the atoll, but only two dozen or so are considered native, or at least indigenous to the Hawaiian archipelago. Among gently sloping dunes, one can spot these low-growing forbs and patches of dense grasses. Bunchgrass / ʻEmoloa / Kāwelu (Eragrostis variabilis), a robust grass endemic to the Hawaiian Islands, is now one of the most common native plants across the atoll landscape, often used as a “warrior species” for erosion control and dune stabilization. Other notable species include abundant and densely growing coastal shrub Naupaka (Scaevola taccada), which encircles the islands; ‘Ilima (Sida fallax), which means “yellow” in Hawaiian, a low-growing plant with small bright golden flowers; and the perennial Sea Purslane / ʻĀkulikuli (Sesuvium portulacastrum), a pioneer species, growing on sunny, windy, sandy beaches, and coastal coralline areas. These species provide important ecosystem services (such as soil stabilization and flooding control), as well as important nesting, foraging, and loafing habitat for a variety of wildlife. But not all plants are so helpful. Golden Crown-beard (Verbesina encelioides) was and continues to be Midway’s Most Wanted. A notorious invasive species, Golden Crown-beard once carpeted the islands with chest-high, impenetrable thickets. Through concerted control efforts by USFWS staff, volunteers, and contractors, Golden Crown-beard now only covers about 1% of the atoll—another step towards restoring Midway as a robust seabird island ecosystem. Yet, Midway is more than meets the eye: beyond the blanket of a several million birds atop three small islands lies an abundant and diverse marine world. Beyond terra firma, Midway’s islands are situated within a large, elliptical barrier reef measuring about 5 miles in diameter. A bright, turquoise-blue lagoon lies within the reef, dotted with numerous patch reefs. Outside of the lagoon, the Refuge boundaries extend another 12 nautical miles, encompassing 580,740 acres of marine resources. A rare view of the "undercarriage" of a Laysan albatross (Phoebastria immutabilis) fledgling as it tries out water for the first time. These birds spend about eight months on land being fed by parents before the relentless call of instinct pushes them to flight and water. Many chicks never see water until their first flight and they will spend the rest of their long lives in it. Photo credit: Dan Clark/USFWS. Located at the northern extent of one of the highest-latitude coral reef ecosystems in the world, the waters within the Refuge are relatively cold, making the area an important location for research on biological diversity as well as the effects of heat-induced coral bleaching. Moreover, Midway (along with the Northwestern Hawaiian Islands) is one of the few remaining predator-dominated coral reef marine ecosystems in North America. Midway’s waters brim with life, including a diverse range of algae, corals, worms, snails, and seashells. A total of 29 species of stony or “hard” coral have been recorded throughout the atoll, along with more than 100 species of algae, including a seaweed species new to science, Dudresnaya babbittiana, and over 250 fish species. Marine habitats, including spurs, grooves, and sand channels, are home to seagrass meadows, urchins, bi-valve clams, sponges, and more. Common species observed include the Rock-boring Urchin (Echinometra mathaei), Long-spined Sea Urchin (Diadema paucispinum), Needle Spine Urchin (Echinostrephus aciculatus), Pied Brittle Star (Ophiocoma pica), Sacoglossan Sea Slug (Plakobranchus ocellatus), and Rhynchocinetes species (shrimp). Midway is also home to the endangered Hawaiian Monk Seal / llio holo I ka uaua (Monachus schauinslandi), which now boasts a local population of greater than 60 seals. Hawaiian Monk Seals are among the rarest marine mammals in the world. Part of the “true seal” family (Phocidae), Hawaiian Monk Seals are one of only two remaining monk seal species; the other is the Mediterranean Monk Seal. A third species, the Caribbean Monk Seal, is extinct. Hunted to the brink of extinction in the late 19th century, Hawaiian Monk Seals have been declining since modern surveys began. In 1976, the Hawaiian Monk Seal was listed as “endangered” under the Endangered Species Act. In addition to the Monk Seals, Hawaiian Green Sea Turtles / Honu (Chelonia mydas) bask on Midway’s beaches and a resident pod of about 200 Spinner Dolphins (Stenella longirostris) cavort and rest in the lagoon. Honu were listed under the Endangered Species Act in 1978. The federally-recognized distinct population of Hawaiian Green Sea Turtles is listed as “threatened.” Globally, Green Sea Turtle numbers are declining. In contrast, the Hawaiian stock has been increasing and population numbers are now approaching pre-exploitation levels. But the turtles’ recovery is not without peril. More than 90% of the Hawaiian population nests at French Frigate Shoals in the Northwestern Hawaiian Islands, making the long-term survival of this population dependent on the health of one tiny speck in the middle of the ocean. They migrate to feed mainly in the coastal areas of the Main Hawaiian Islands, exposing them to numerous risks. Limited nesting locations and important coastal foraging areas for Green Sea Turtles are found throughout the Pacific Islands. E komo mai (welcome) to the Midway Ohana. Stay tuned to learn about the atoll’s albatross ambassador, the Midway Mōlī! This blog post is part of an ongoing, collaborative series between Island Conservation, Northern Illinois University (myself), and the U.S. Fish and Wildlife Service. Be sure to check back here for more information about Midway and ongoing conservation and restoration efforts!
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About MeWieteke Holthuijzen: budding environmental scientist, passionate birder. Archives
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