First, this is the first time I've posted to this listserv, so hopefully
I've done it correctly. At first I was going to respond to Michael
directly, but then thought it may be beneficial for others as well. For
those who are not aware, bat populations in parts of the US and Canada
are declining at an alarming rate due to the spread of a devastating
disease known as White Nose Syndrome (WNS). So taking on bat research
must be done thoughtfully and carefully. Unless you are directly
involved in a carefully designed research project and are properly
trained, please stay out of caves as this is where they appear to be
most vulnerable.
Michael, you should definitely check out Kunz and Parsons, and get some
hands-on experience, as Liz suggested, because sampling for bats is not
the easiest skill to develop. Also, as you are likely aware, bats in
your area are in a great deal of trouble with the spread of WNS. I'm not
sure what the protocol is down in the US, but here in Canada we are
attempting to get the species affected by WNS listed. This means there
will be strict protocols in place determining how we can sample bats.
So, if you are looking for something new for the sake of learning, and
don't have a particular research question, I would stick with acoustic
monitoring to minimize your impact on an incredibly vulnerable group of
animals.
Acoustic sampling for bats is often favoured over capturing bats because
it is less invasive. However, acoustic sampling takes an incredible
amount of work as differentiating species based on their echolocation
calls can be very difficult. Bats can adjust their calls depending on
habitat structure, what they are doing at the time, and how many other
bats are in the area. This can make it difficult to identify species,
and especially difficult to differentiate between species with similar
call features. Based on your location, I'm guessing this would be the
case for you. On top of that, the range of bat detectors is strongly
influenced by the species (high frequency calls break down more quickly
than lower frequency calls, for example) and by habitat structure (some
frequencies travel better in open spaces and some break down quickly in
cluttered environments). So, you have to carefully consider what you
want to know in order to properly design your study. In addition, I
would caution against relying on automated measurements that some
packages offer. I've never trusted these as it has been my experience
that there is a huge amount of noise around each call. Also, given this
huge variation, it is advisable to capture bats and obtain "reference
calls" in different areas to be sure you are identifying species
correctly. But, as I mentioned, I would try to limit how often you
capture bats as they are under a lot of stress in your area.
All that said, bat research can be very rewarding, and acoustic sampling
can usually give you a lot more information than capturing bats; bats
are pretty good at avoiding nets and traps, thus limiting your sample
sizes. Moreover, different species are more vulnerable to capture than
others (e.g., some fly higher, others are more maneuverable and can
therefore get around nets and traps more readily).
As mentioned in earlier replies, you can certainly get training to help
you identify species using acoustic sampling. I'll also pass along
information for a colleague of mine located in BC who offers training in
acoustic monitoring. She has recently been hired by Titley Electronic
(the producer of Anabat and Analook) and travels to different areas to
offer workshops. You can find information at
http://www.batsrus.ca/index.html.
I hope this helps.
Krista
--
Krista Patriquin, PhD Biology
Writing Advisor
Dalhousie University
Halifax, NS
