An Introduction to Bats

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An Introduction to Bats
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BATS

• Creepy, blind, blood-sucking RODENTS of the
  night.right?

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What do YOU know about bats????

• Bats are flying rats
• Bats will attack you for no reason
• Bats will fly into your hair
• Bats are blind

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Actually..
Nobody likes me.

• Those are all just
• BAT MYTHS
• Bats wont fly into your hair or attack you
• They arent blind at all
• And they arent even rodents

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The Only Way Rodents Can Fly
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Common Questions about Bats
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So, What ARE Bats???

• Class Mammalia
• Order Chiroptera (hand-wing)
• Suborder Megachiroptera- flying foxes
• 1 Family, 166 species
• Suborder Microchiroptera- micro bats
• 16 Families, 759 species

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Bat Stats

• 4,200 species of mammals
• 1,000 species of bats
• Of these, 88 are tropical

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Bats Unique Small Mammals

• Long lived (some up to 30 years)
• Possibly due to reduced metabolic activity during
  torpor (40 of the year in some species).
• Low fecundity
• Temperate zone bats are monestrous and usually
  have 1 young/yr
• Exceptions are the red bat (twins and triplets
  are common) and the southeastern myotis (twins
  are common)
• Long period of infant dependency
• 2 month gestation and 1 month of infant
  dependency
• High survivorship
• 50-80 chance of surviving each year once
  adulthood is reached (Findley 1993).
• Common predators of bats are owls, snakes, hawks
  and feral cats

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What do Bats Eat?

• FRUIT- frugivory
• FLOWERS- nectar or pollen
• CARNIVORES- birds, reptiles, amphibians
• FISH- highly specialized carnivores
• BLOOD- sangrivory
• INSECTS- aerial or foliage gleaners

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How do Bats Fly?

• Bats are the only mammals capable of TRUE powered
  flight

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Bats Actually Fly With Their Hands, Not Their
Arms!
Illustration from BCI Educators Activity Book
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What is Echolocation?

• Microbats use ECHOLOCATION for navigation and
  prey capture

Animation from www.batcon.org.
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More About Echolocation

• 1700s Lazarro Spallanzani first proposed bats
  could see with their ears
• 1930s Donald R. Griffin of Harvard coined term
  echolocation
• Not all bats echolocate- just Microchioptera
• Most echolocation calls are between 9 to 200kHz
• Humans can only hear up to 20 kHz
• Bat detectors allow us to hear bat calls
• Can ID bat species by their echolocation calls

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Why Are Bats Important?

• Bats are important pollinators of many plant
  species including the agave plant (ie. Tequila),
  the saguaro cactus and many rainforest plant
  species
• Bats are vital for the control of insect
  populations

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Economic Importance of Bats in Agriculture

• The story of Mexican free-tailed bats in Central
  Texas
• Bracken Cave 20 million Mexican free-tailed
  bats (single largest aggregation of mammals in
  the world)
• Central Texas caves, including Bracken Cave, are
  summer maternity roosts for 100 million Mexican
  free-tailed bats
• It is estimated that these bats eat about 2
  million lbs of insects every night

Photo from www.batcrew.com
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Tadarida brasiliensis Mexican Free-tailed bat
Photo From BCI www.batcon.org
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Bats Aloft A Study of High Altitude Feeding

• Bat Biologists Knew
• Mexican Free-tailed bats fly as high as 10,000
  ft.
• Densest aggregations are at 600 3,200 ft.
• Entomologists Knew
• Corn earworms are one of the most destructive Ag.
  pests in US
• Corn earworm moths fly at same altitudes during
  dispersal
• Early June emerge from Lower Rio Grande Valley
  of Mexico
• 3 days after peak emergence in Mexico, moths
  begin laying eggs on agricultural crops in
  Central Texas
• 3 weeks later, next generation spreads north
  through the Central US
• Question
• Could the free-tail bats be eating
• corn earworm moths?????

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The Problem

• Helicoverpa zea
• Corn Earworm

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Bats Aloft Partners

• Dr. Gary F. McCracken, University of Tennessee
• Dr. Wayne Wolfe and Dr. John Westbrook of USDA
  Research Station in College Station, TX
• U.S. Weather Service
• Bat Conservation International

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A Problem of Timing

• Researchers needed to know if the moths were
  flying in TX at the same time the bats were
  feeding
• Seemed improbable because the moths were still
  traveling to TX when the bats emerged in the
  evening
• Plus, other studies had shown that moths were
  only 30 of the bats diet - EXCEPT..
• Bats forge 2x a night- early evening and early
  morning
• Further investigation showed that in early June,
  bats only ate 37 moths in the early evening but
  96 moths during their dawn feeding!

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Doppler Radar Images

• Images From McCracken, G. F. 1996. BATS 14(3)
  7-10 on www.batcon.org

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Ok, Bats are Beneficial- but What About Bats and
RABIES???

• Bats ARE carriers of rabies
• Rabies caused by a bullet-shaped virus of the
  genus Lyssavirus. It causes a very serious viral
  infection of the Central Nervous System
• Rabies can only be transmitted through saliva or
  spinal fluid, not blood or urine
• If you are exposed, you will need post-exposure
  vaccinations ASAP (series of 5 itty-bitty shots
  in the arm)
• FYI- Raccoons pose the most serious risk of
  rabies in South GA. Surprisingly, otters are
  also a risk

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Rabies Prevention

• DONT HANDLE WILD MAMMALS, including bats!!!!!!
• Keep your pets vaccinated
• If you think you have been exposed, seek medical
  attention promptly

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Histoplasmosis

• Histoplasmosis is caused by a ground fungus
  Histoplasma capsulatum
• It causes flu-like symptoms which, in rare cases,
  can be quite serious
• Severity of disease is related to dosage of
  exposure (number of spores inhaled)
• It is most often associated with bird droppings,
  but bat and rodent droppings also pose a risk-
  esp. in hot, humid climates
• Keep your home and outbuildings free of fecal
  material

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Bats in Georgia16 Species
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Family Vespertilionidae

• The Evening Bats

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Rafinesques Big-eared BatCorynorhinus
rafinesquii

• Rare- possibly declining in numbers due to
  habitat loss
• Roosts in abandoned buildings, hollow trees and
  caves in or near bottomland hardwood habitats
• Will glean insects from foliage or capture them
  in flight
• Easily disturbed

Photo From BCI www.batcon.org
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Southeastern MyotisMyotis austroriparius

• Species of Concern by USFWS
• Cave bat eastern US
• Roosts in hollow trees, culverts, and bridges in
  areas w/o caves
• Also associated with bottomland hardwood areas
• Only Myotis bat to have twins

Photo From BCI www.batcon.org
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Big Brown BatEptesicus fuscus

• One of the most common bats in urban areas and
  bat houses
• Often roots in buildings- prefers snags in
  natural habitat
• Often return to maternity roost where they were
  born
• Forage in a variety of habitats

Photo From BCI www.batcon.org
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Eastern Red BatLasiurus borealis

• Solitary, tree-roosting bat
• Hangs by one foot
• Will also hibernate in leaf litter on forest
  floor
• Used to form large daytime migratory flocks in
  1800s
• 2-5 young (usually 3)

Photo From BCI www.batcon.org
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Hoary BatLasiurus cinereus

• Solitary, roots among foliage on forest edges
• Can fly 24 miles in one night while foraging
• Territorial over foraging sites
• Often migrate with bird flocks
• One of the most widespread bats in N. America
• Hawaiis only native land mammal

Photo From BCI www.batcon.org
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Evening Bat Nycticeius humeralis

• Abundant in SE US
• Forest bat- hardly ever in caves
• Little is known about its migration patterns

Photo From BCI www.batcon.org
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Eastern PipistrellePipistrellus subflavus

• Common in forest edges and near agricultural
  areas
• One of first bats to emerge in evening
• Forage high in canopy
• Will hibernate in caves and in culverts

Photo From BCI www.batcon.org
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Northen Yellow BatLasiurus intermedius

• Roosts year-round in Spanish moss and palm fronds
• Abundant on the coast
• Will forage over sand dunes and beaches
• Typically have 3 pups

Photo From BCI www.batcon.org
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Family Molossidae

• The Free-tailed Bats

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Mexican Free-tailed BatTadarida brasiliensis

• Another very common urban and bat house bat
• One of most widely distributed mammals in Western
  Hemisphere
• Highly gregarious
• Much of the population is migratory

Photo From BCI www.batcon.org
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Other Bats in Georgia

• Silver-haired bat
• Seminole bat
• Gray myotis
• Small-footed myotis
• Little brown myotis
• Eastern long-eared myotis
• Indiana myotis- ENDANGERED

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Bat Conservation
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Threats to Bat Populations

• Habitat destruction/fragmentation
• Loss of historical roost sites
• Disturbance of roost sites, esp. caves
• Ignorance
• General public negative attitudes
• Scientific Very little is known about the
  distribution, numbers and specific requirements
  of most bat species

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Hot Topics in Bat Research

• Phylogeny and evolution
• Functional morphology
• Echolocation
• Conservation Biology
• North American Bat Conservation Partnership
  (NABCP) Strategic Plan

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Top 5 Conservation Research Goals (NABCP)

• Goal 1 Identify key resources- Flyways, roosts,
  drinking and foraging habitats
• Goal 2 Establish baseline populations and
  trends
• Goal 3 ID species requirements and limiting
  factors
• Goal 4 Describe, quantify, and monitor the
  effects of current land-management practices and
  other human disturbances on bats.
• Goal 5 Quantify the economic and social impacts
  of North American bats.

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Top 4 Management Goals (NABCP)

• Goal 1 Develop management standards and
  guidelines for bats, including them in existing
  management plans for other wildlife and
  associated habitat.
• Goal 2 Identify, protect, and enhance key
  roosting, feeding, and drinking resources for
  bats. Reestablish bat populations to the extent
  necessary.
• Goal 3 Incorporate bat conservation language
  into existing statutes for wildlife protection.
• Goal 4 Integrate strategic plans for bats into
  other existing plans and initiatives.

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Common Methods For Studying Bat Populations

• Population Surveys Counts
• Direct Roost Counts
• Nightly Dispersal Counts
• Maternity Roost Counts
• Ultrasonic Bat Detectors
• Simple handheld
• ANABAT (records for computer analysis)
• Population Surveys Captures
• Mist Nets
• Harp Traps
• Trip Lines (over water sources)

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Bat Management
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Basic Habitat Requirements for Bats

• ROOST SITES
• Including maternity, bachelor and hibernation
  roosts
• Caves, hollow trees, stumps, live trees,
  abandoned buildings, bridges, culverts, etc.
• FORAGING HABITAT
• Waterways, roads, pipelines, forests, edges,
  clearings, beaches, etc.
• WATER SOURCES
• Lakes, rivers, streams, bays, stock tanks,
  swimming pools, etc.

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General Practices that Benefit Bats

• Protection of known or potential roosts,
  including snags, hollow trees, abandoned
  buildings, caves, bridges, etc.
• Creating artificial roosts
• Maintaining water quality (BMPs)
• Wise use of insecticides
• Keep cats indoors!
• Leave known bat populations undisturbed

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Bat House Design

• Bat houses should have the following specs
• AT LEAST 2 ft. tall and 14 in. wide- bigger is
  better!
• Have a 3-6 inch landing strip covered with
  plastic hardware cloth below entrances
• Inner partitions (1-4) should be ½ to 1 in.
  apart and covered with plastic hardware cloth or
  roughened manually
• Ventilation slot 6 in. from bottom of house

Photo From BCI www.batcon.org
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Bat House Construction and Wood Treatment

• Use plywood, cedar or a combination
• Exterior of house Apply 3 coats of dark or
  medium colored exterior grade, water-based paint
  or stain
• Interior of house Apply two coats black,
  exterior grade, water-based stain
• Caulk all seams

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Bat House Placement

• Full all day sun is best- minimum is 6 hours of
  sun exposure a day
• Place near water if possible
• Mount house on a pole 15-20 ft. high
• Make sure entrance is unobstructed

Photo From BCI www.batcon.org
Photo From BCI www.batcon.org
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Bats That Will Use Bat Houses In Georgia

• Little brown myotis
• Southeastern myotis
• Eastern pipistrelle
• Big brown bat
• Evening bat
• Mexican free-tailed bat

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Recommended Steps for Bat Management

• Conduct bat surveys
• Identify roosts- esp. maternity roosts
• Provide artificial roosts (bat boxes)
• Incorporate bat management practices into your
  overall management plan
• Work with neighboring landowners to provide as
  much habitat as possible
• Discourage human disturbance of bat roosts
• Monitor bat populations and make the data
  available to researchers

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For More Information

• Bat Conservation International
• www.batcon.org
• Buzbees Bat House
• www.batbox.org
• Bat CREW
• www.batcrew.com