Listing
Apr 14, 1970
Apr 14, 1970 Listing (Endangered)
Notice of Proposed Rulemaking (Endangered Species Conservation); 35 FR 6069
- Publication type: Proposed
Item 1
FWS Focus
Overview
Characteristics
Overview
The California least tern is the smallest of the tern species. By the 1960s, its habitat availability had been severely reduced due primarily to coastal development and intense human recreational use of beaches. As a result, population numbers for the species have diminished from uncountable thousands to several hundred by 1970, when the species was listed as endangered.
Scientific Name
Sterna antillarum browni
Common Name
California Least Tern
FWS Category
Birds
Identification Numbers
Characteristics
Characteristic category
Habitat
Characteristics
Habitat
California least terns nest on 23 sites, some of which are natural and others are man-made and include beaches close to river mouths, estuaries and coastal embayments. These sites require active management activities, including protection from disturbance and predators, and or, vegetation management to retain habitat suitability.
Characteristic category
Physical Characteristics
Characteristics
Size & Shape
California least terns measure fewer than 10 inches in length, with a total wing length of approximately 4 inches.
Weight
California least terns weigh between 45 and 55 grams.
Color & Pattern
This subspecies has a short, forked tail, and a long, slightly decurved, tapered bill. Males and females are both characterized by a black cap, gray wings with black wingtips, white underbody, orange legs and a black-tipped yellow bill.
Characteristic category
Life Cycle
Characteristics
Reproduction
California least terns are present in the United States during the breeding season, which extends from mid-April to mid-September. They nest in colonies of typically 15 to 300 pairs.
Characteristic category
Food
Characteristics
Food
California least terns forage in nearshore waters, estuaries and river mouths for slender-bodied fish such as anchovies and topsmelt.
Geography
Characteristics
Range
The least tern breeds along the Pacific coast from San Pablo Bay, California, in the north, to San Jose del Cabo, in the state of Baja California Sur, Mexico, to the south.
Timeline
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