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Summer Bat Count


Historically, bats only used trees as summer roosts. But as more and more habitat is loss to development, man-made structures such as buildings, bridges, and bat boxes have become important bat dwellings. The Summer Bat Count involves finding a roost and counting the bats as they exit in the evening.


First, you will need to find a location where bats are roosting. Bats in natural roost You may already know of a church, house, barn, bat box, or tree that bats roost in during the daylight hours. Or take a walk around your neighborhood at dusk and try to track flying bats back to the roost they've exited.

Once you have located a bat roost, you will need to visit it four times between late May and August. Surveyors need to arrive at the roost site half an hour before sunset and position themselves for easy viewing of bats exiting the structure. Surveyors will locate where the bats are exiting and count them as they fly out. This may require more than one surveyor if exits are located on more than one side of the structure. A map of the roost location and a data sheet will be filled out and returned to the Conserve Wildlife Foundation of NJ (CWF).


Although bats have a bad reputation, they are actually one of the most beneficial animals to people. All of New Jersey's bats feed almost exclusively on night-flying insects, including mosquitoes. A single bat may eat half or more of its own body weight in insects each night, up to 3000 per hour! Just 150 big brown bats can eat enough cucumber beetles each summer to protect farmers from 18 million of the beetles' larvae that cost close to a billion dollars annually. Many garden pests can detect the feeding sounds that bats make and avoid areas where bats are present. Without bats, we would be much more dependent on toxic pesticides to control insect pests.

In western states and tropical rain forests, bats play key roles in pollinating flowers and dispersing seeds for important agricultural plants. Bat droppings, or "guano", make excellent fertilizer and some caves are actually mined for guano.


More than half of American bat species are in severe decline or are already listed as endangered. Worldwide, losses are occurring at alarming rates. Adverse human impacts include habitat destruction, direct killing, vandalism, disturbance of hibernating and maternity colonies, and use of pesticides and other chemical toxins. The Summer Bat Count will help to educate the public about the importance of bats and encourage people to take steps towards their conservation.

In New Jersey, we currently know very little about the status and distribution of bats. The Endangered and Nongame Species Program hopes the Summer Bat Count will document summer roosting locations throughout New Jersey and help to create a range map for the state's nine species of bat. The information will also help to determine roosting and foraging requirements and contribute to the protection of bats in New Jersey.


Studies have shown that less than half of 1% of bats contract rabies. People are far more likely to contract rabies from raccoons, cats, dogs, skunks, and other animals. The best advice, as with any wild animal, is to leave them alone and do not handle them.


Bats do not attack humans and want nothing to do with being tangled in your hair. In fact, bats can detect objects as fine as a single human hair in total darkness. Bats are not aggressive but may fly close to people while feeding on flying insects.


To learn more about the Summer Bat Count and become involved visit on the CWF site. If you know of a location where bats roost in the summer, or have questions about the program, please contact MacKenzie Hall, Private Lands Biologist for the CWF, at 908.782.4614, Ext. 104 or via e-mail at

Bat Fact Sheet (pdf, 130kb)

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Department of Environmental Protection
P.O. Box 402
Trenton, NJ 08625-0402

Last Updated: January 30, 2014