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An Introduction to Bats

An Introduction to Bats BATS Creepy, blind, blood-sucking RODENTS of the night….right? 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 Nobody likes me…. Actually….. Those are all just BAT MYTHS

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An Introduction to Bats

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  1. An Introduction to Bats

  2. BATS Creepy, blind, blood-sucking RODENTS of the night….right?

  3. 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

  4. Nobody likes me…. Actually….. • Those are all just BAT MYTHS • Bats won’t fly into your hair or attack you • They aren’t blind at all • And they aren’t even rodents……

  5. The Only Way Rodents Can Fly

  6. Common Questions about Bats

  7. 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

  8. Bat Stats • 4,200 species of mammals • ~1,000 species of bats • Of these, 88% are tropical

  9. 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

  10. 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

  11. How do Bats Fly? • Bats are the only mammals capable of TRUE powered flight

  12. Bats Actually Fly With Their Hands, Not Their Arms! Illustration from BCI Educator’s Activity Book

  13. What is Echolocation? • Microbats use ECHOLOCATION for navigation and prey capture: Animation from www.batcon.org.

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

  15. 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

  16. 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

  17. Tadarida brasiliensis Mexican Free-tailed bat Photo From BCI: www.batcon.org

  18. 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?????

  19. The Problem Helicoverpa zea Corn Earworm

  20. “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

  21. 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!

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

  23. 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

  24. Rabies Prevention • DON’T HANDLE WILD MAMMALS, including bats!!!!!! • Keep your pets vaccinated • If you think you have been exposed, seek medical attention promptly

  25. 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

  26. Bats in Georgia:16 Species

  27. Family Vespertilionidae: The Evening Bats

  28. Rafinesque’s 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

  29. 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

  30. 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

  31. 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 1800’s • 2-5 young (usually 3) Photo From BCI: www.batcon.org

  32. 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 • Hawaii’s only native land mammal Photo From BCI: www.batcon.org

  33. 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

  34. 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

  35. 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

  36. Family Molossidae The Free-tailed Bats

  37. 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

  38. Other Bats in Georgia • Silver-haired bat • Seminole bat • Gray myotis • Small-footed myotis • Little brown myotis • Eastern long-eared myotis • Indiana myotis- ENDANGERED

  39. Bat Conservation

  40. 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

  41. Hot Topics in Bat Research • Phylogeny and evolution • Functional morphology • Echolocation • Conservation Biology • North American Bat Conservation Partnership (NABCP) Strategic Plan

  42. 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. Top 5 Conservation Research Goals (NABCP)

  43. 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.

  44. 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)

  45. Bat Management

  46. 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.

  47. 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 (BMP’s) • Wise use of insecticides • Keep cats indoors! • Leave known bat populations undisturbed

  48. 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

  49. 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

  50. 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 isunobstructed Photo From BCI: www.batcon.org Photo From BCI: www.batcon.org

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