Inside a Bat Survey
For a mist net survey, you must be like the bat. This means staying up all night in bug infested areas, snacking on Doritos or, if you’re actually a bat, insects. About three to five large nets are set up in various locations. They are checked at regular intervals and can be hoisted up and down via a pulley system to get bats out. Caught bats are carefully untangled and put in a paper lunch bag (yes!) which is then rolled down to prevent the bat from escaping. In the order that they were caught, bats are taken to an outdoor lab area and “processed”. The lab consists simply of a table with the necessary equipment and tools: data sheets, a small light, bands, tweezers, etc.Time of capture, species, weight, age (juvenile or adult), sex, and forearm length are all recorded. Bats are checked to see if they are
lactating (females) or scrotal (males) and are banded. Sometimes DNA samples are taken in the form of fur clippings and small tissue samples.
Of course, bats are also checked for indicators of WNS, such as light colored splotching of the wings. During this time of the year, the fungus isn’t usually visible because the bats are active and grooming. Once they go into hibernation, the fungus accumulates and becomes easier to see.
Because of WNS, the utmost care is taken to avoid potentially transferring the fungus from one bat to another. Lysol wipes, latex gloves, and rubbing alcohol abound. There is also a final, lengthy (over an hour) decontamination process of everything at the end of the night. This involves some people running around in gas masks and goggles, with giant rubber gloves and headlamps. Exactly what the occasional 3 A.M. driver-by thinks, I don’t know, but I can’t help but wonder if this is how many government conspiracy theories start.
If you are a caver or anyone else who needs to decontaminate clothing or equipment that may have come in contact with spores of the WNS fungus, you can find the current federal guidelines here. You will need Woolite and either bleach or industrial concentration Lysol (Lysol IC).
How can you tell the difference between an adult and a juvenile?
Young bats have hollower bones. When holding their extended wing over a light, certain joints will appear to have a “bubble” in them. Adults do not have this.
How many bats do you normally catch?
In my personal experience, 11-72. However,sometimes no bats are caught. Bat feeding behavior varies depending on the weather and other factors. If it’s an especially busy night with lots of waiting bats piling up, biologists make sure that all bats are either processed or released within 30 minutes of being caught.
What types of bats do you catch?
Once again, my personal experience has been four to eight different species in a night. Common bats to catch have been the northern long-eared bat Myotis septentrionalis, the little brown bat Myotis lucifugus, and the eastern red bat Lasiurus borealis. We’ve also caught big brown Eptesicus fuscus, hoary Lasiurus cinerius, eastern small-footed Myotis leibii, tri-colored Pipistrellus subflavus, and seminole bats Lasiurus seminolus this season. North Carolina has 17 different species of bats.
How long does a bat survey normally take?
Setup usually starts around 6:00 or 7:00 p.m. and ends between 2:30 and 4:00 a.m.
Are bats ever injured?
Occasionally, however most nights there are either no injuries or only very minor ones. If a bat is seriously tangled the net can be cut away to safely remove it, but sometimes bats hurt themselves when struggling in nets and paper bags. A serious injury might be a broken bone, a more minor example is an oral cut from their teeth getting tangled in the net. Often bats have previous injuries from before being caught in a net, such as rips in their wings. A healthy bat can heal minor wing tears and punctures in two to three weeks. Injured bats are often not banded and do not have DNA samples taken.
How many people are on a survey team?
Usually 4-10 people, depending on the number of volunteers and whether or not the site has had high catch rates in the past.
How often do you see bats that have already been tagged?
Sometimes a bat tagged earlier in the night is recaptured. In this case the bat is simply untangled and re-released. At one site many bats had already been tagged by a different organization. Usually we don’t see bats that were tagged by NC WRC in previous years, even though for the most part the same sites are surveyed year after year.
Do you ever catch anything besides bats in the nets?
Yes. Sometimes at dusk birds get caught in the net. Once an extremely cute but disgruntled flying squirrel was caught.
Do you name the bats?
No, but sometimes we make them talk in funny voices.