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Bats

Identification
Biology
Inspection
Control
Pro Tips

Identification

  • The most common species of bats in our service are the Little Brown Bat and the Big Brown Bat. The Evening Bat and the Mexican Free-tailed bat are also in some areas we service.
  • Little Brown Bats are small. Their wingspan is 9 - 10 inches, with a body smaller than your hand. They live in large colonies of up to 300 in a house. They migrate, leaving in about October and coming back to the same house about May. They don’t go far when they migrate – usually, their winter hibernation sites are within a hundred miles or so of their summer roosts.
Little Brown Bat
  • Big Brown Bats are the larger of the two species. Their wingspan is 13 - 14 inches, and the body is wider than your hand. They live in small colonies, usually only 5 or 6 in a house. They do not migrate to a warmer climate. They sometimes stay in the same house over the winter, moving down into the walls or under cover on the attic floor, where the temperature is above freezing. More frequently, though, big brown bats move out in the fall and seek a nearby cave, storm sewer, or other cool, humid winter hibernation site.
Big Brown Bat
Bat Species By State

Biology

  • Breeding period: Autumn
  • Gestation:  60 days
  • Birth period:  May- June
  • Litters per year: 1
  • Litter size:  1
  • Feeding period:  Night
  • Bats feed on moths, flies beetles, mayflies, stoneflies winged ants, gnats and other small flying insects.
  • Range
Little Brown Bat Range
Big Brown Bat Range

Inspection

  • Bat inspections are the most highly detailed of all nuisance wildlife inspections.
  • Customers typically request inspection for bats because of a live bat in a living space.  They may also hear scratching, squeaking, or rustling noises in walls or ceilings.  The appearance of unknown droppings on exterior areas may also cause the client to call for inspection.
  • Remember to use the information provided by the customer as a starting point for you inspection. This may come from direct communication with the customer or the notes from client service detailed in the work order/proposal. 
  • Start the inspection by walking the perimeter of the home looking at the roofline.  Obvious entry points would include gable vents, dormer corners, soffit returns, roof junction and ridge vents, fascia gaps along soffits and gable rises and chimneys. Grease marks may be present at very active entry points.
  • Look for signs of bat activity including droppings on roofs, stuck to siding, in gable vents, or on the ground around chimney bases, porches, decks, etc.  Bat guano will be small, cigar shaped and will crumble easily due to insect exoskeletons that will be in droppings.
  • If the attic inspection is not done at the initial appointment, an attic inspection will be needed at the time bat doors are removed.  At this time confirm that bats are no longer present in the attic and provide a quote for attic clean up and restoration if needed.
  • Attic inspection may be needed when exterior inspection is not enough to determine the presence of bats. In the attic bats may be present in rafters and gable vents. The presence of guano inside the attic can also confirm the presence of bats.
Bat Entry Point with Grease Marks
Bat Guano
Bat Guano

Control

  • There are no pesticides labeled for use against bats, and certain species may be protected by law. In any event, bats are considered desirable because they consume vast amounts of flying insects such as midges, mosquitoes, and other night fliers.
  • Occasionally, we are called upon to remove a single bat from a home; this is done carefully, and simply involves picking the bat up and removing it from the premises. Tools needed are a bite-proof glove (welder's glove) and a big gulp size cup. Pick up the bat and put in the cup. It will not be able to spread its wings to fly or crawl out. Follow state laws and release it outside, away from the customer.  
  • Our bat control efforts consist mainly of excluding bats from a structure. This work is a combination of sealing holes and gaps that bats use to gain entry to a building, and installing one-way bat doors that bats can use to leave the building at night when it is time to begin flying about and foraging for food. The bat doors are designed so that when bats try to re-enter the building at the end of the night’s feeding, they cannot get in through the bat door. They simply fly away and look for another suitable roost.
  • After bats have been excluded from a house or other building, it may be necessary to eliminate a left-over population of bat parasites, such as bat ticks or bat bugs (a close relative of bed bugs). This would be done by applying insecticides into the cracks, crevices and void spaces where the insects were hiding and through which they gained access to the occupied spaces of the building.
  • We may also provide a quote for attic cleanout and restoration if there are issues with bat guano in the attic.
Bat Valve
Attic Clean Out, Before and After

Pro Tips

  • Unexperienced technicians should contact a supervisor or experienced technician to assist with bat inspection and exclusion.  Technicians must be bat certified in order to perform bat inspections by themselves. 
  • Bats can carry rabies. If a customer has had close contact with a bat or has concerns about being bitten or scratched refer them to immediately contact a doctor.  No medical advice should be given; leave it to the medical professional.  A bat can be killed and left with the customer for rabies testing upon request. 
  • Many customers who have found a live bat in the living space of the home assume that the bat came down the chimney or through an open window. This is not likely.  Bats almost always enter a home through the attic and then the living space through a crack, gap, or hole on the interior of the home. Once a bat is in the living space, it may gravitate to the fireplace because it can feel a draft of air from the chimney.
  • Make sure to follow all state laws when dealing with bats.  Most bats carry some type of state or federal protection.
  • Ohio is the only state with laws preventing the use of bat removal (installing bat doors) during the birthing season.  No bat doors can be hung from May 15th-July 31st. Ohio does allow night watches to determine population size. If 2 night watches conclude less than 15 bats present the doors can be hung. If over 15 bats are present, the home owner must call ODNR for an additional permit. ODNR can deny the request.
  • In all the other states we can legally hang bat doors year-round, but for active colonies or inspections that identify juvenile bats always wait to hang the doors. Make sure to discuss this with the customer. Bats are not intentionally killed since they are a protected species and it is bad for the ecosystem. Hanging bat doors in the birthing season can lead to more bats entering the living space, bad odor, increase chances of contact and diseases, and other pests entering the living space like bat bugs and flies. Follow all state recommendations as closely as possible.
  • Bat Birthing Season by State:   
  •         OH:  May 15 - July 31 ODNR State Law                                  
  •         PA:   May 15-  July 31 State Recommendation
  •         IN:   May 15 – Aug 15 State Recommendation
  •         MN:  Jun 1  - Aug 15 State Recommendation
  •         MI:  June 1- Aug 15 State Recommendation
  •         KY:   May 15 - Aug 15 State Recommendation
  •         IL:  May 15- Aug 5  State Recommendation
  •         WI: June 2-Aug 15 State Recommendation
Juvenile Bat