Stanislaus River Basin and Calaveras River Water Use Program
Threatened and Endangered Species Report - March 1995
Bay Delta and Special Water Projects Division, CA Dept of Fish and Game
Long-eared Myotis
Myotis evotis
Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or
Endangered
Life History
This bat can be distinguished by its large ears, extending about 7 mm past the muzzle, a
long pointed tragus, gradually sloping forehead, black wing membranes and ears, and light to
dark brown fur. Body measurements are: total length, 75 to 97 mm; foot, 7 to 10 mm (Ingles
1965); ear length, 18 to 22.4 mm; forearm length, 35.5 to 41; greatest length of skull, 15 to
16.4 (Hall 1981).
Myotis evotis is distributed from British Columbia, south to Baja California and east to
North Dakota, and then southward through South Dakota, Nebraska, and New Mexico;
excluding the southern deserts of Arizona and California. Two subspecies exist in North
America ( M.e. evotis, M.e. pacificus) and both are found in California (Hall 1981).
The long-eared myotis is found throughout California except in the hot central valley and
the dry hot deserts of southern and southeastern California. This bat can be found in brush,
woodland and forests habitats up to 9,000 feet (2700 meters), possible preferring coniferous
woodlands and forests, yet is uncommon in most of its range (Zeiner 1990).
M. evotis feeds on many different arthropods and eats more beetles than other myotis. It
feeds over water, among trees and shrubs within four feet (12 meters) of the ground and
catches insects while in flight, feeding from the ground, or gleaning from foliage. This bat is
capable of hovering and feeds on the edges of habitat or over water. Emerges late in the
evening to forage.
The long-eared myotis can be found roosting in buildings, rock crevices, under bark and
in snags and may use caves as night roosts. Usually roosts singly or in small groups of 12-30
animals, including maternity colonies. Mating likely occurs in the fall with usually one young
born in May to June. The young are able to fly by early August. Winter habits of the long-eared
myotis are poorly known, but they may make short movements to hibernating sites.
Findings and Conclusions
The destruction of suitable roosting sites and maternity colonies is probably the main
reason for decline. Pesticide use, eradication from buildings and destruction of foraging
habitat could also play a critical role.
The upper portion of the Stanislaus River is in the range of the long-eared myotis. Our
surveys occurred during the colder part of the year and did not resulted in the capture of any
animals. The long-eared myotis is expected to occur along the Stanislaus River.
The project should have minimal impacts on the long-eared myotis as long as foraging
areas and roosting sites are not destroyed. Further surveys for foraging and roosting areas
should be carried out and sites identified.
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