RANGE:

Euderma occur in British Columbia west to South Dakota, south to Mexico and west through California to southern Oregon. The distribution of populations is highly spotty, likely as a result of the habitat requirements of this species. In Idaho, populations occur in the south western corner of the state. An unvouchered capture along the Salmon River in Nez Perce County exists. Two voucher specimens have been collected in Idaho.

DESCRIPTION:

The spotted bat is distinctly colored with a blackish upper fur with patches of white over each shoulder and at the base of the tail. The ears are pinkish, long (over 40mm), and translucent in living individuals. This is the only Idaho species that has an audible echolocating call within the range of human hearing.

HABITAT:

Spotted bats have been collected in desert pinion-juniper woodlands near sandstone cliffs or over streams and water holes in coniferous forests with rock cliffs nearby. Individuals normally roost in deep rock crevices of canyon and cliff walls but specific roost characteristics are not well documented.

Two cave sightings have been reported, but likely represent unusual conditions that led to temporary use. The first specimen collected in Idaho was found under a tree in Canyon County.

DIET:

Euderma feeds primarily on noctuid moths.

ECOLOGY:

Foraging activity in this bat seems to vary geographically, but often occurs over wet meadows. In British Columbia, individuals exited their roost approximately one hour after sunset and returned shortly before sunrise. In Texas, individuals apparently either exit later or drink water late as they are netted after midnight, a situation also observed in Oregon. Some research suggests this bat maintains exclusive foraging areas but tolerates overlap by other individuals while foraging. Fewer than one hundred specimens of this bat exist in museums. As a result of rarity, most netted individuals are immediately released by individuals conducting surveys.

REPRODUCTION:

A single young is born in early summer. Females with young have been observed in Wyoming during August and the actual birth of one young has been documented. The pattern of breeding and hibernation is poorly known. In Utah, individuals have been reported flying in mid winter over frozen water.

IMPORTANT STATE REFERENCE:

Doering, R.W. and B.L. Keller. 1998. A survey of bat species of the Bruneau-Jarbridge River Area of southwestern Idaho with special reference to the occurrence of the spotted bat (Euderma maculatum). Technical Bulletin No. 98-18. Idaho Bureau of Land Management. 29pp.

IMPORTANT GENERAL REFERENCE:

Watkins, L.C. 1977. Euderma maculatum. American Society of Mammalogists, Mammalian Species, 77:1-4.