Southern Yellow Bat (Lasiurus ega)

Texas Status
Threatened
Protection Status Notes
This bat's status is unknown, though it may be expanding its range northward as a result of the widespread introduction of ornamental palms in southeastern Texas. L. ega is not listed by the U.S. Fish and Wildlife Service. However, Texas Parks and Wildlife Department has posted it on its threatened species list.
Description
Lasiurus ega is a medium-sized bat with dull, sooty yellow fur. Like other yellow bats, its tail membrane is entirely furred above and it lacks distinctive white markings on its shoulders and wrists. It has a forearm length of 43-49 mm and weighs 11-14 g. The southern yellow bat is most easily confused with the northern yellow bat where the two species occur together in southeastern Texas. However, the southern yellow bat is smaller with a forearm length of 49 mm or less, versus 51 mm or more for the northern species.
Life History
The Southern Yellow Bat is a subtropical, generally solitary species which lives year-round in southern Texas. These bats are thought to mate in the fall or early winter. Most females give birth to two or three young in late May or early June. Nothing is known about the bat's life span.

The Southern Yellow Bat's feeding habits have not been investigated, though it is presumed to eat small- to medium-sized flying insects.
Habitat
In Texas, the Southern Yellow Bat roosts primarily beneath the hanging dead fronds of palm trees year-round. It is best known from natural groves of palm trees along the Rio Grande near Brownsville, but it also uses ornamental palms as far north as Corpus Christi. Southern and Northern Yellow Bats share roosts in Washington fan palms of Nueces County.
Distribution
The Southern Yellow Bat can be found in the southern areas of California, Arizona and Texas where it has been recorded from Cameron, Kleberg, and Nueces Counties. Its range extends through northeastern Mexico into Central America.
Threats and Reasons for Decline
The practice of removing old palm fronds deprives southern yellow bats of roosting space in many locations. Pesticides used in mosquito control are the most important cause for concern.
Ongoing Recovery
At the moment, many people in the United States find it distasteful to leave dead fronds on their palm trees, even though they provide useful insectivores with prime roosting habitat. Land managers should consider promoting a passive approach to maintaining palm trees in urban areas by allowing fronds to remain on trees. A minor change in our cultural taste in landscaping may be the greatest help we can provide for the southern yellow bat. With the increasing numbers of ornamental palm trees being planted in commercialized areas of South Texas, these bats may actually be gaining roosts.
Other
This bat is poorly studied in the United States. Knowledge of its feeding requirements is entirely lacking.
For more information
  • Additional details can be found in the online version of The Mammals of Texas for the Southern Yellow Bat

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