Jul 6, 2012 – Bat Battles

QUESTION:

What time of year can bats be removed in California?

ANSWER:

This is going to depend somewhat on the species of the bat, but in general bats seem to give birth anywhere from May to early July, so definitely right now would not be a good time to exclude the adult bats if you are dealing with a structural infestation. Bats are not always protected animals, but given the benefit they provide when living outside where they belong they should be preserved if at all possible. Excluding the adults while the young are still inside a structure and unable to leave is, obviously, going to result in the death of those young, and beyond just the tragic loss this causes it also leads to inside problems with odors, flies, and other things associated with a dead animal. 

From resources I have it then appears that you cannot count on young bats being able to leave on their own any sooner than at least 6 weeks after they are born. One western species takes 6 weeks to mature to the point it can fly. Another common California species can fly at 3 to 4 weeks but will continue to nurse for another several weeks. Mexican free-tailed bats in California are one of our most common species, and their young are born from June into July, meaning it may not be until late August when you can be fairly certain these young are capable of getting out of that structure on their own. 

So, at least at this date it would be improper to seal up a structure if bats may have been producing offspring within it. From state to state this also is going to vary as bats may breed later in cooler northern regions or sooner in the southern states. Checking with your local University Extension office should provide some good information local to you on this. 


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