Laysan Millerbird
Encyclopedia
The Laysan Millerbird was a subspecies of the Millerbird
, similar in appearance to the remaining subspecies, the Nihoa Millerbird
. Its dorsal
side was brown, and its belly was grayish. Its name derives from its favorite food, several species of moths of the genus Agrotis
(such as the endemic and likewise extinct Agrotis laysanensis
) commonly referred to as "millers" (Butler & Usinger, 1963).
, where it was endemic, in the 1890s (Udvardy, 1996). After the fateful introduction of domestic rabbit
s in 1903, which nearly denuded the island of vegetation in the next few years, the birds probably declined rapidly. Supposedly, there were 1500 still alive in April 1915 as reported by the USCGC Thetis expedition (Clapp et al., 1996), but a thorough 1911 census by the Iowa State College expedition had found only "a few" (Dill & Bryan, 1912), as did a brief visit in February 1916. As land bird populations on Laysan fluctuate heavily and because there was considerable poaching for the Japanese millinery trade in the 1910s, the supposed 1915 figure cannot be discounted, but it seems highly improbable. At any rate, the 1923 expedition
by the reported only one unconfirmed sighting which seems to have been erroneous (Olson, 1996). Thus, it can be concluded that the bird disappeared at some time in the late 1910s.
As the vegetation disappeared, the bird suffered increased egg predation by Laysan Finch
es (Telespiza cantans), Ruddy Turnstone
s (Arenaria interpres) and Bristle-thighed Curlew
s (Numenius tahitiensis), as well as increased competition for food and nesting habitat; a small patch of tree tobacco (Nicotiana glauca
) was the only locality left where the millerbird, the Laysan Rail
(Porzana palmeri) and the Laysan Apapane (Himatione sanguinea freethi) could nest with a reasonable chance of success. Additionally, the moths which formed its main food source became likewise extinct or exceedingly rare as their food plants were eaten by the rabbits, and thus the only significant food left were brine flies, which, though abundant, would also be utilized by the other land birds and the Laysan Duck
(Anas laysanensis), all of which were more aggressive than the millerbird. It is most likely that the Laysan Millerbird was the first of the three avian taxa to have gone extinct on Laysan, the last individuals of the Apapane disappearing in a sandstorm around April 24, 1923 and the rail also disappearing around that time.
Millerbird
The Millerbird is a species of Old World warbler in the family Acrocephalidae. It had two subspecies, A. f. kingi and A f. familiaris. The latter, the Laysan Millerbird, became extinct sometime between 1916 and 1923. The former, the critically endangered Nihoa Millerbird, remains the only race...
, similar in appearance to the remaining subspecies, the Nihoa Millerbird
Nihoa Millerbird
The Nihoa Millerbird is a subspecies of the Millerbird. It gets its name from its preferred food, the Miller moth. The five-inch long Millerbird has dark, sepia-colored feathers, white belly, and dark beak...
. Its dorsal
Dorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
side was brown, and its belly was grayish. Its name derives from its favorite food, several species of moths of the genus Agrotis
Agrotis
Agrotis is a genus of moths of the Noctuidae family. A number of the species of this genus are extinct.Many of the species are of great importance as cutworms, major agricutural pests whose larvae hide by day and emerge at night to feed. The name cutworm refers to the habit of the larvae, of...
(such as the endemic and likewise extinct Agrotis laysanensis
Laysan Noctuid Moth
The Laysan Noctuid Moth was a species of moth in the Noctuidae family. This species is now extinct.It was endemic to Laysan Island, one of the Outlying Hawaiian Islands, United States....
) commonly referred to as "millers" (Butler & Usinger, 1963).
Extinction
Very tame, it was abundant on LaysanLaysan
Laysan , located northwest of Honolulu at N25° 42' 14" W171° 44' 04", is one of the Northwestern Hawaiian Islands. It comprises one land mass of , about 1 by 1.5 miles in size . It is an atoll of sorts, although the land completely surrounds a shallow central lake some above sea level that has...
, where it was endemic, in the 1890s (Udvardy, 1996). After the fateful introduction of domestic rabbit
Domestic rabbit
A domestic rabbit, or more commonly known as simply the rabbit, is any of the several varieties of European rabbit that have been domesticated....
s in 1903, which nearly denuded the island of vegetation in the next few years, the birds probably declined rapidly. Supposedly, there were 1500 still alive in April 1915 as reported by the USCGC Thetis expedition (Clapp et al., 1996), but a thorough 1911 census by the Iowa State College expedition had found only "a few" (Dill & Bryan, 1912), as did a brief visit in February 1916. As land bird populations on Laysan fluctuate heavily and because there was considerable poaching for the Japanese millinery trade in the 1910s, the supposed 1915 figure cannot be discounted, but it seems highly improbable. At any rate, the 1923 expedition
Tanager Expedition
The Tanager Expedition was a series of five biological surveys of the Northwestern Hawaiian Islands conducted in partnership between the Bureau of Biological Survey and the Bishop Museum, with the assistance of the U.S. Navy. Four expeditions occurred from April to August 1923, and a fifth in July...
by the reported only one unconfirmed sighting which seems to have been erroneous (Olson, 1996). Thus, it can be concluded that the bird disappeared at some time in the late 1910s.
As the vegetation disappeared, the bird suffered increased egg predation by Laysan Finch
Laysan Finch
The Laysan Finch is a species of finch in the Hawaiian honeycreeper subfamily, Drepanidinae, that is endemic to the Northwestern Hawaiian Islands. It is one of four remaining finch-billed Hawaiian honeycreepers, and is closely related to the smaller Nihoa Finch. The Laysan Finch is named for...
es (Telespiza cantans), Ruddy Turnstone
Ruddy Turnstone
The Ruddy Turnstone is a small wading bird, one of two species of turnstone in the genus Arenaria. It is now classified in the sandpiper family Scolopacidae but was formerly sometimes placed in the plover family Charadriidae...
s (Arenaria interpres) and Bristle-thighed Curlew
Bristle-thighed Curlew
The Bristle-thighed Curlew, Numenius tahitiensis, is a large shorebird that breeds in Alaska and winters on tropical Pacific islands. It has a long, decurved bill and bristled feathers at the base of the legs. Its length is about 43 cm and wingspan about 84 cm...
s (Numenius tahitiensis), as well as increased competition for food and nesting habitat; a small patch of tree tobacco (Nicotiana glauca
Nicotiana glauca
Nicotiana glauca is a species of wild tobacco known by the common names tree tobacco and incorrectly also Mustard tree. Its leaves are attached to the stalk by petioles , and its leaves and stems are neither pubescent nor sticky like Nicotiana tabacum...
) was the only locality left where the millerbird, the Laysan Rail
Laysan Rail
The Laysan Rail or Laysan Crake was a tiny inhabitant of the Northwest Hawaiian Island of Laysan. This small island was and still is an important seabird colony, and sustained a number of endemic species, including the rail. It became extinct due to habitat loss by domestic rabbits, and ultimately...
(Porzana palmeri) and the Laysan Apapane (Himatione sanguinea freethi) could nest with a reasonable chance of success. Additionally, the moths which formed its main food source became likewise extinct or exceedingly rare as their food plants were eaten by the rabbits, and thus the only significant food left were brine flies, which, though abundant, would also be utilized by the other land birds and the Laysan Duck
Laysan Duck
The Laysan Duck , also known as the Laysan Teal because of its small size, is an endangered dabbling duck endemic to the Hawaiian Islands...
(Anas laysanensis), all of which were more aggressive than the millerbird. It is most likely that the Laysan Millerbird was the first of the three avian taxa to have gone extinct on Laysan, the last individuals of the Apapane disappearing in a sandstorm around April 24, 1923 and the rail also disappearing around that time.