Wink,
To clarify my response at any given time about bats isn't because they are on the decline everywhere, or related to the population, but rather related to methodology
that excludes bats whenever possible without using tactics at times of day, time of year, etc... when the operator or those they instruct may cause harm, injury or death.
I'm not saying Kasey's clients are doing this either by using water, however it would depend on all those questions 1-3 above.
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Now, to the idea of how many bats there are or how many constitutes a healthy population, that is a much bigger ball of wax.
First bats being able to move about the landscape to reach food and water much further than terrestrial wildlife in a single night, means bat night roosting
in one area on a porch could be day roosting in someones attic on the other side of town. All depends of course on the resource availability and behavior
of the particular species, prey abundance, etc...
We as nuisance wildlife control operators though have an interesting view into the lives of bats that is nearly 100% through those who call us to invite us
to resolve their issues in exchange for our service fees.
Where the rubber meets the road however, how do we gauge the number of bats by the number of people who either see, finally detect or someone tells them
they have a bat problem?
My average clients have had bats at least a couple years or more based on evidence and their description as well. Many that called this year said "we've had them
for years now but think we may need to address the issue as it has...."
This of course wouldn't help with a yearly feel of "plenty of bats" or "we've got more bats than ever" as the people are completely random in who calls and why.
Yes most folks who notice a decent sized colony exiting the home or hear them in the attic are going to call that first time they notice it, however I and I'm sure I'm
not the only one, have had folks who didn't really notice till odor issues appeared or a friend mentioned the odor when visiting and they investigated.
With not only multiple species on the landscape, yes fewer tend to be in homes, you'd also have to factor in, how many big brown bats are counted, how many little
brown (also in WI), even just between those two and with random calls and not waiting each night and counting the number of bats when doing exclusion, how
would what we might see tell any story other than the clients I have this year have bats?
Some areas I work in nearly every structure has bats, literally, you can move 50' and see another colony sometimes the same species, sometimes another, but
I cannot translate that into "we have healthy populations of bats" as I can't know what that number truly is to be "healthy."
Many bats are either on or are getting put on lists for state threatened, sensitive, endangered, as well as federally being looked at due to WNS, however it isn't the only threat.
We all know in our realm of dealing with homeowners, structures and bats, there are those doing exclusion, then there are those who are still killing bats, using all kinds
of methods I won't repeat here for not wanting to provide any ideas to any newbie who stumbles on this thread.
However suffice to say, bats have enough threats in the world and though I'm sure we have in ways benefitted bats through our structures, they use our structures due to absence
of the natural structures that they evolved to utilize. They have adapted well, however we of course don't like sharing our homes with them for some obvious reasons, so when
a colony is called in, depending on who picks up the call and lands the client, that colony could be headed for death, or it could be excluded and left to look for another roost, next door, down the block, across town, etc...
That is another factor in the "we've got plenty" scenario when looking at the jobs we do.
If we are excluding bats for clients, we aren't killing them so they are moved to another area and if they are structure obligate bats like big browns, little browns or others in various regions, they can be seen by two operators in the same year (spring and fall exclusions).
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I'll summarize though, I don't care if someone told me bats of some species are at a steady healthy level, I would never change my tactics from those I feel produce the most beneficial outcomes for client and bat alike.
To me it isn't a pick and choose and I find no reason to not always be looking for the options that satisfy that desire to do so.
Whats funny is most articles written in the general news and folks in most discussions are nearly always looking at "bats" as all the bats and not concerning their minds with how many species are in the area, how they differ in many ways including threats, numbers, etc....
Thats about the best way I can think of to say, we have no idea how many bats are on the landscape based on the random nature of folks who call us each year. If calls go up, it can be due to better advertising, a different referral source (I have a new guy that sent me 40 new bat clients this year, does that mean there are more bats? Nope, just have a new lead from someone who is in houses in the right areas every day), people are more educated on bats due to WNS and conservation groups pushing bats more in the media....
Ultimately trends can only be utilized if you have enough stable sites or control groups, if you look at the same nests every year for bald eagle nesting for example, you can definitely see the reproductive success over time and track it....
With multiple species of bats, random nature of calls, the only way people track how many bats is generally through winter counts that are done in known hibernacula or in caves/mines, etc... during various seasons.
On the landscape most research is more about presence/absence where they are looking for what species are utilizing this area at this time of year.... Very hard to do any population trends other than counting little bodies in caves each winter.
Anyway as a small operator who uses few sources of gaining bat jobs, when my jobs go up, it isn't related to bat numbers, it is related to folks noticing they have bats and finding me instead of another operator....
Without 100% of homeowners, operators and others reporting each year, species, number in colony, etc... no way to build anything more than a strong feeling in my little toe that bats are doing well.....
I do appreciate you always giving me time to sit and ponder some of these questions so that I can think through the best way to answer them....
Good practice for many audiences frankly....