Middleton Island

The island is thought to be only about 5,000 years old, having formed recently due to a continental shelf area that is subject to tectonic uplift. During the 1964 Alaska earthquake, the second largest earthquake ever recorded on earth, the island rose an additional {{convert|12|ft}} above sea level, converting submerged seafloor into new land and estuary, in the process expanding the size of the island from approximately {{convert|2200|to|3200|acre}}, or 45%. The new land continues to evolve through longshore deposition, sedimentation, and plant succession.

According to the Institute for Seabird Research and Conservation:

:Driven partly by changes wrought by the earthquake and partly by large-scale oceanographic factors, bird populations on Middleton are more dynamic than possibly anywhere else in Alaska. The island hosts substantial numbers of kittiwakes, cormorants, gulls, murres and puffins, but no species is stable–huge fluctuations, both up and down, have occurred since regular monitoring began in the 1970s.

The seabird population has risen and fallen dramatically ("bird populations on Middleton are dynamic"). The explanations for this include changes in the landscape brought by the 1964 earthquake which reduced the sea-edge cliff habitat; changes in food availability caused by natural and man-made factors (warmer years correlate with less food availability); a significant increase in the bald eagle predator population.

The island has a feral population of rabbits since the 1950s. The rabbits provide food for eagles and owls during the winter, but the population rebounds in the summer. There are no other naturally occurring mammals on or near the island, other than seals, sea lions, the occasional sea otter, and several species of whales.

The island was historically used seasonally by Chugach and Eyak Indians. The earliest known permanent inhabitants were settlers in the fox-farming industry during the late 1890s through the 1920s. During World War II, the U.S. Coast Guard built a small communications station on the island, the first of successive U.S. Government operations to follow, including the Civil Aeronautics Administration, U.S. Air Force (Middleton Island Air Force Station), Federal Aviation Administration (Middleton Island Airport), and various wildlife and land management agencies.{{refn|group=nb|Agencies include: United States Fish and Wildlife Service (USFWS); Alaska Outer Continental Shelf Environmental Assessment Program (OCSEA); Alaska Maritime National Wildlife Refuge Seabird Monitoring (AMNWR)}}

Most of the acreage on the island is owned by Chugach Alaska Corporation, one of 13 Alaska Native regional corporations in the state. The Federal Aviation Administration retains some 200 hundred acres in support of radar installations for weather and air traffic monitoring. The privately owned biological station (182 acres) is the other substantial holding.

Middleton Island Marine Biological Station studies seabirds and is located on {{convert|182|acre}} in and around the former Middleton Island Air Force Station. Researchers live on the island year round, plus visiting students and researchers. It is owned and managed by the Institute for Seabird Research and Conservation, it is the non-profit's primary holding and mission. Field operations are funded in part by Gulf Watch Alaska (Exxon-Valdez Oil Spill Trustee Council) and receive funding mainly through a cooperative agreement with the U.S. Geological Survey. Middleton Island has the longest running time series of seabird monitoring of any Alaska breeding site. It began in 1956, in anticipation of the Airforce base that would be built in 1958, when researcher Robert Rausch conducted the first floral and faunal survey of the island. {{As of|2024}}, the station reported between 2 and 12 researchers lived on the island year-round, the higher number in summer.

The SS Coldbrook was a Hog Islander merchant ship, built in 1919, that grounded off Middleton Island in 1942 after being chased ashore by a Japanese submarine, the captain choosing to beach the ship to save the lives of his crew.{{cite book|title=United States Coast Pilot Alaska Part II, Yakutat Bay to Arctic Ocean|last=U.S. Coast & Geodetic Survey|date=1947|edition=5th|location=Washington|publisher=U.S. Government Printing Office|url=https://books.google.com/books?id=yxV-AAAAIAAJ|page=90}} The ship could not be salvaged and remained battered in the surf. During the 1964 Alaska earthquake, the ground rose {{convert|12|ft}}, and the Coldbrook was left beached at high-tide and out of the pounding surf.{{cite book|title=Tectonics of the March 27, 1964, Alaska Earthquake|first=George|last=Plafker|date=1969|publisher=U.S. Government Printing Office|location=Washington|series=Geological Survey Professional Paper No. 543-I|page=I-14|url=https://books.google.com/books?id=Iw9_Jz5VAWYC}} The now {{years ago|1919}}-year-old rusting hull is home to thousands of nesting seabirds, which are studied by researchers at the Middleton Island Marine Biological Station.{{cite web |title=The Middleton Island Marine Biological Station |access-date=2024-04-29 |url=https://middletonisland.org/ }}{{cite web |last=Peck-Richardson |first=Adam |title=Middleton Island Video Tour |work=Hatfield Marine Science Center |date=March 19, 2021 |access-date=2024-04-29 |url=https://www.youtube.com/watch?app=desktop&v=K7SR7l_8zd0 |via=YouTube}}

Middleton Island has a subpolar oceanic climate (Köppen: Cfc).

{{Weather box

| location = Middleton Island, Alaska

| single line = Y

| Jan record high F = 46

| Feb record high F = 46

| Mar record high F = 47

| Apr record high F = 51

| May record high F = 63

| Jun record high F = 67

| Jul record high F = 70

| Aug record high F = 72

| Sep record high F = 62

| Oct record high F = 59

| Nov record high F = 53

| Dec record high F = 46

| year record high F = 72

| Jan avg record high F =43.0

| Feb avg record high F =42.2

| Mar avg record high F =43.7

| Apr avg record high F =47.4

| May avg record high F =53.7

| Jun avg record high F =58.6

| Jul avg record high F =63.0

| Aug avg record high F =63.5

| Sep avg record high F =59.1

| Oct avg record high F =52.8

| Nov avg record high F =47.3

| Dec avg record high F =43.2

| year avg record high F =65.4

| Jan high F = 36.2

| Feb high F = 36.2

| Mar high F = 37.9

| Apr high F = 42.1

| May high F = 46.2

| Jun high F = 51.4

| Jul high F = 56.4

| Aug high F = 57.8

| Sep high F = 54.5

| Oct high F = 47.3

| Nov high F = 42.1

| Dec high F = 37.6

| year high F = 45.5

| Jan mean F = 33.3

| Feb mean F = 33.3

| Mar mean F = 34.9

| Apr mean F = 38.5

| May mean F = 42.9

| Jun mean F = 47.9

| Jul mean F = 52.8

| Aug mean F = 54.4

| Sep mean F = 51.1

| Oct mean F = 44.1

| Nov mean F = 39.3

| Dec mean F = 34.6

| year mean F = 42.2

| Jan low F = 30.4

| Feb low F = 30.3

| Mar low F = 31.9

| Apr low F = 34.9

| May low F = 39.5

| Jun low F = 44.3

| Jul low F = 49.2

| Aug low F = 51.0

| Sep low F = 47.7

| Oct low F = 40.9

| Nov low F = 36.5

| Dec low F = 31.6

| year low F = 39.0

| Jan avg record low F = 19.6

| Feb avg record low F = 20.9

| Mar avg record low F = 22.9

| Apr avg record low F = 27.9

| May avg record low F = 34.5

| Jun avg record low F = 40.3

| Jul avg record low F = 45.1

| Aug avg record low F = 46.3

| Sep avg record low F = 41.7

| Oct avg record low F = 34.1

| Nov avg record low F = 27.9

| Dec avg record low F = 22.2

| year avg record low F = 14.5

| Jan record low F = 9

| Feb record low F = 6

| Mar record low F = 13

| Apr record low F = 14

| May record low F = 23

| Jun record low F = 36

| Jul record low F = 42

| Aug record low F = 42

| Sep record low F = 36

| Oct record low F = 29

| Nov record low F = 13

| Dec record low F = 12

| year record low F = 6

| precipitation colour = green

| Jan precipitation inch = 4.14

| Feb precipitation inch = 3.40

| Mar precipitation inch = 3.01

| Apr precipitation inch = 3.39

| May precipitation inch = 3.34

| Jun precipitation inch = 2.22

| Jul precipitation inch = 3.13

| Aug precipitation inch = 5.18

| Sep precipitation inch = 6.83

| Oct precipitation inch = 7.35

| Nov precipitation inch = 5.96

| Dec precipitation inch = 5.17

| year precipitation inch = 53.12

| Jan snow inch = 6.8

| Feb snow inch = 6.5

| Mar snow inch = 6.0

| Apr snow inch = 2.7

| May snow inch = 0.1

| Jun snow inch = 0.0

| Jul snow inch = 0.0

| Aug snow inch = 0.0

| Sep snow inch = 0.0

| Oct snow inch = 0.8

| Nov snow inch = 2.0

| Dec snow inch = 7.5

| year snow inch = 32.4

| source 1 = WRCC{{cite web

| url = https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?ak5868

| title = MIDDLETON ISLAND, ALASKA (505868)

| publisher = Western Regional Climate Center

| access-date = July 8, 2022

| archive-url = https://archive.today/20230518043739/https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?ak5868

| archive-date = 2023-05-18}}}}

• List of islands of Alaska

{{reflist|group=nb}}

{{Reflist}}

• [http://www.audubon.org/important-bird-areas/middleton-island Important Bird Areas : Middleton Island, Alaska]
• [https://www.youtube.com/watch?app=desktop&v=K7SR7l_8zd0 Middleton Island Video Tour]

{{Coord|59.44|-146.33|type:isle|display=title}}

{{Authority control}}

Category:Islands of Alaska

Category:Islands of Chugach Census Area, Alaska

Category:Islands of Unorganized Borough, Alaska

Category:Uninhabited islands of Alaska