San Clemente loggerhead shrike
Conservation status
Critically Imperiled  (NatureServe)[1]
Endangered (ESA)[2]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Passeriformes
Family:	Laniidae
Genus:	Lanius
Species:	L. ludovicianus
Subspecies:	L. l. mearnsi
Trinomial name
Lanius ludovicianus mearnsi Ridgway, 1903

The San Clemente loggerhead shrike (Lanius ludovicianus mearnsi) or San Clemente Island loggerhead shrike is a subspecies of the loggerhead shrike that is endemic to San Clemente Island, California.^[3]

Description

The San Clemente loggerhead shrike is a passerine bird of medium size. Around its eyes, it has black feathers, a color which is also found in the tail and on the wings. On its back, it has gray feathers. The underside of the bird is white. It also has patches of white on its wings and tail.^[2] The San Clemente loggerhead shrike has the darkest gray feathers compared to its other loggerhead shrike counterparts.^[4]

Genetics/Phylogeny

It has been known that the San Catalina loogerhead shrike populution had clustered closely with the San Clemente loggerhead shrikes, so there has been historic gene flow between the two. Still, the San Clemente loggerhead shrike is now its own subspecies.^[5]

Behaviour

The San Clemente loggerhead shrike is also called a "butcher bird" since it can take animals similar to its own size such as mammals and reptiles.^[6] Loggerhead shrikes have "tomial teeth". These projections in their mandible jab at the spinal cord of their prey to paralyze them.^[7] Similar to other loggerhead shrikes, San Clemente loggerhead shrikes reach maturity after a year and live in monogamous pairs. The pair both care for the eggs and young. The clutch size is usually around five eggs.^[8]

Distribution and habitat

The San Clemente loggerhead shrike is native to San Clemente Island, a small island off the coast of California, United States. The island is owned by the United States Navy, and is a valuable asset to the Pacific fleet, allowing for ship-to-shore, air-to-ground, and ground-to-ground operational training. Shrikes typically occupy wooded canyons on the west side of the island, and sagebrush-dominant habitat on the eastern escarpment.

Conservation

Since the 1880s, the San Clemente loggerhead shrike's habitat has been threatened by domestic animals, primarily goats, imported to San Clemente Island. The predation of the shrikes by cats and rats also played a role.^[6] By the early 1900s, the bird's population had declined to about 20, but stabilized. The Navy began removing introduced species in 1973.^[9] In 1977, the San Clemente loggerhead shrike was listed as endangered by the United States government, with an estimated population of 50.^[2] Between 1982 and 1999, the bird's population was measured between 14 and 33 birds, bottoming out in January 1998.^[10][9] The removal of feral goats and sheep was completed in 1993.^[9]

In 1996, the Institute for Wildlife Studies conducted video research on the shrike for the Navy. In 1997, they were asked to come up with a strategy to raise the bird's numbers.^[10] A captive breeding program was launched in 1992 at a cost of $3 million per year, and new policies were instituted to help the shrike.^[11][12] For example, snipers must aim around bird nests when practicing.^[13] Thanks to the program, the bird's population reached 135 (captive and wild) specimens by 2004.^[9] In 2009, an estimated 82 pairs were alive; this number decreased to 41 until 2017 due to drought in Southern California.^[3]

References