Important Bird Areas

Middleton Island

Alaska

Middleton Island, in the northern Gulf of Alaska, lies about 80 km south of Prince William Sound. This low-lying, unforested island of 2 x 8 km is only about 4,300 years old. The island is a Registered Natural Landmark, designated by the National Park Service, for its geological history. Human uses of the island go back to visits (possibly occupation) by Chugach Natives. Fox farming was initiated in the late 1800s, and European hares were introduced in the 1950s.

Middleton Island is a highly dynamic environment and is still in transition following an uplift of 2.7-3.5 m in the Alaskan earthquake of 1964, which added an extensive area of intertidal and supratidal lands. Its avifauna includes the largest concentration of Black Oystercatchers anywhere on the Pacific coast, as well as good numbers of other breeding shorebirds and seabirds. The island?s nesting population of Black-legged Kittiwakes has been monitored and studied intensively since the mid-1970s. Middleton Island is also known as a stopover site for migrants, and as many as 130 species of birds have been recorded there in late September and early October, even though only 20 or so species regularly breed on the island. There has long been interest in establishing and maintaining a permanent biological field station.

Ornithological Summary

In terms of avian conservation, the Black Oystercatcher is the most noteworthy species on Middleton Island. No Black Oystercatchers or Rhinoceros Auklets were detected on Middleton Island in June 1956, but there were Black-legged Kittiwakes, Tufted Puffins, Common Murres, and Thick-billed Murres. The Alaskan earthquake of 1964 changed the topography of the island, creating extensive additional rocky intertidal and supratidal habitat and accelerating the erosion of cliff habitats used by nesting seabirds. In 1976, long-term, annual monitoring of seabird populations and productivity was initiated. In that year, one pair of nesting Black Oystercatchers was observed. By 2002, however, there were 171 territorial pairs and a total of 718 individuals on the island, based on rigorous surveys of shoreline habitats. Breeding densities of Black Oystercatchers on Middleton Island are the highest recorded for any population in Alaska and nesting success in 2001 and 2002 was higher than that of any other population on the Pacific coast.

Also in 1976, about 1,700 Rhinoceros Auklet burrows were counted on Middleton Island, but there were 5,480 burrows by 2003. In 1956, Glaucous-winged Gull was absent as a breeding species, but there were about 20,000 individuals in the mid-1990s. Numbers of Pelagic Cormorant nests have varied from 4,498 in 1990 to 1,329 in 2006.

Other species of interest include Black-legged Kittiwake, which increased from 10-15,000 pairs in 1956 to more than 166,000 individuals in 1981, but subsequently declined to about 12,470 individuals in 2007. Numbers of murres (both Common Murre and Thick-billed Murre) increased from about 400 individuals in 1956 to about 8,000 in 1988 and declined to 3,500 or fewer in recent years. Middleton Island is one of only a few oceanic islands inhabited by breeding Canada Geese, which first started nesting there in 1981. Genetically, these geese may be related to island-nesting geese in Prince William Sound or upper Cook Inlet.

Conservation Issues

Due to its remote location and limited access, there are few threats to avian habitats on Middleton Island. Although the FAA maintains air traffic aids, the aids are largely automated. Use of much of the privately-owned land (CAC) is limited by easement to the federal government and managed as part of the AMNWR

A business consortium owns a small upland property, where a long-running research program is based on seabirds nesting on an abandoned radar tower and other structures. The property was originally purchased as a possible staging area for oil development, but this use did not materialize. Representatives of the original property owners have been accommodating to research activities. The greatest threat is simply that multiple heirs will cloud future ownership, but there is the possibility that the property would be sold for incompatible uses. The presence of a covered, former military dump site on this property, with possible contaminant issues, complicates possibilities of the land being conveyed to public or other ownership.

Introduced European hares are present and may limit numbers of burrow nesting seabirds, such storm-petrels or ancient murrelets. Heavy grazing by the hares must also make the island less attractive as nesting habitat for some shorebirds, such as short-billed dowitchers.

Middleton Island clearly is a young island (estimated 4,300 yrs) and still in a post-earthquake transition. Erosion and vegetation are altering previously steep, bare cliff sides, and the island is becoming less attractive for cliff-nesting seabird species, such as Black-legged Kittiwake. Ultimately, if the upland portions of the island were to become forested, it would further change the composition of the avifauna. Habitat succession is not likely to affect Black Oystercatcher habitat.

Ownership

Middleton Island is under public and private ownership. The specific area included within the proposed IBA is in three parts: 1) federal ?public domain? intertidal and supratidal lands, which were exposed by the Alaska earthquake and surround the island; 2) that portion of the island uplands managed by the US Fish and Wildlife Service as part of the Alaska Maritime National Wildlife Refuge (AMNWR); and 3) a small parcel of land privately owned by a small business consortium, which is the site of long-term seabird research. With regard to the land managed as part of the AMNWR, the Chugach Alaska Corporation (CAC; an Alaska Native entity) has fee simple title to this land, but the federal government retains an easement for purposes of wildlife habitat protection and management. The remainder of the island, not proposed as part of the IBA, is owned by the Federal Aviation Administration or by CAC (but is not part of the AMNWR).

Habitat

Middleton island is unforested, with an abundance of low-sloping or level gravel and sandy beaches and rocky intertidal zone. Upland habitats are mostly grassland rising in a series of terraces to the high point of the island. What were once steep sea cliffs above the pre-earthquake high-tide line are now rapidly eroding and heavily vegetated. Marsh and wetland habitats now occur at the base of these slumping cliffs.

Land Use

Middleton Island is uninhabited except for occasional research biologists and Federal Aviation Administration personnel. The island is visited infrequently by birdwatchers, waterfowl and rabbit hunters, and beachcombers. Most of the area within the proposed IBA, however, is essentially unused and rarely visited. The one exception is the research site (business consortium property with abandoned radar tower and other structures), which is seasonally occupied. The proposed IBA does not include the large airstrip and other abandoned buildings at the north end of the island.