Two million dead bats

[dfcaver]

Including 530,000 just in Vermont. This is the first "update" of the much quoted "million" figure that I've seen.

http://www.news7newslinc.net/around-nek ... ont-042011

[PYoungbaer]

dfcaver,

It's not an update at all, just a figure pulled from a publication on the potential impact of bats on agriculture.

Many people -scientists included - have questioned the long-used "over a million" number. It was an extrapolation compiled by the scientists and wildlife manager at the Austin, Texas WNS symposium in 2009. Many have felt uncomfortable with that oft-quoted by the media number, and attempted to be more precise by counting population decline comparisons at actual sites. This method arrived at 1.1 million, but was before this winter, and showed wide variation in coverage by state. New York had a lot of sites; MA and NJ had only one or two. That 1.1 million estimate was prepared for Sen. Frank Lautenberg, prior to his introduction of his Wildlife Emergency legislation.

I sent a query to all of the federal and state biologists in the affected states last month, and got push back from USFWS. They pledged to try to compile a more accurate number for the WNS Symposium May 17-19. Whatever we get will be only the best estimate, as there is no way to count carcasses, since they disappear quickly to predators and over the countryside.

I'll pass on what we hear.

[wyandottecaver]

not exactly on topic but close.

This year the USFWS, which had formerly played a very minor role in Indiana bat surveys, essentially took them over. In the process they changed the survey methodology that had been used for decades. This has had 2 immediately noticeable effects:

1) instead of surveying and having compiled the data for 25-30 caves by this point, they surveyed about 9 and have only preliminary numbers for 6. This is due to the adoption of counting noses in photos...30,000+ noses in some cases rather than the traditional "x" number of bats per square foot. Thus a crew of temp employees has been hired to squint at photos and count..... While supposedly more accurate and faster, what noses you see depends on zoom and resolution and trying to keep track of how the photos should be stitched is an issue.

2) based on parallel testing last time when they did some photos as a pilot, the Photo method consistently yields higher numbers...often as much as 30% higher. Thus based on data so far, hibernacula that would have seen losses from last year are "about even". How convenient.

[PYoungbaer]

New York has been using the photographic method for years, and demonstrated it at Hellhole last winter. It means far less time in the hibernaculum, and thus, less disturbance for the bats. There are some tricks to photographing, such as using a laser pointer for focusing the camera, but it's a good method.

That said, until it's been used for several years, comparing longitudinal data is tough. It always has been. Look at the numbers for Mount Aeolus Bat Cave in Vermont. I don't think there were ever two counts with the same methodologies, until the last couple of years. Even now, Scott Darling estimates that the cave held up to 300,000 bats, although the highest actual count was only about 23,000. There was one earlier estimate - an outlier by all other counts, in the 300,000 range, but it was an extrapolation based on an estimate of how many bats flew by stationary observers in a period of time - and then multiplying. Hardly precise.

I don't know of any reason why cavers can't assist on these counts - it doesn't have to be just UWFWS. As long as protocols are followed and people trained in bat identification, many more sites can be surveyed.

[wyandottecaver]

Peter,

I'm not knocking the photo method per se', but ESPECIALLY with WNS in Indiana this year why would you suddenly drop your baseline method?........

I wasn't present at this years counts just hearing it 2nd hand. However, the time savings seems to be very much influenced by the morphology of the clusters. In caves (mostly smaller hibernacula) where you have scattered individual clusters that you can get with 1 or a few shots its indeed much faster (at least in cave). In many of our caves, with large, complex clusters that might require a dozen or more photos per cluster...just the process of recording what photo was pointed where and what area you have and havent already photographed gets tedious.

In the case of Indiana our surveys had been conducted with essentially the same methods by essentially the same people for at least 10 years, and the primary person had been doing it for nearly 30. Again, Im just hearing it 2nd hand, but everyone says the USFWS essentially shut the door on many of the previous folks. So while people who had participated and even co-authored several previous survey reports sat idle, USFWS personnel are now the new "experts". It was spin control out the ying yang IMHO.

[pub]

Since 2006, the little brown bat has been reduced from a population of about 60 million to just 60,000 in NY State.

See article at: Unprecedented Wildlife Crisis: Frogs, Bees, Bats, Is There a Connection?

Let’s do the math, 60,000,000 - 60,000 = 59,940,000
Just in NY State, Incredulous!

[PYoungbaer]

That number is wildly inaccurate. The most solid number to date is the 1.1 - 1.2 million put together by USFWS for Sen. Lautenberg. However, that number did not include this winter's mortalities. I pushed to get a number by the Symposium, but that was not done. I do suspect the actual number is closer to 2 million at this point, but will continue to push for the best number possible.

That said, the article's statement of losing over 59 million little browns is pure poppycock - unless the rapture was for them, and not humanity

[wyandottecaver]

I'd laugh if someone suggested there were 6 million Little Browns in NY before WNS. There probably weren't 600,000, but 60 million? I doubt there are that many bats of every species combined east of the mississippi.

[pub]

Kudos Peter! Thanks to your comments on the article, it has been edited to read:

Since 2006, over a million little brown bats have died from an epidemic fungal disease known as White Nose Syndrome.

…the figure of 60 million bats down to 60,000 is wildly inaccurate. In testimony prepared for U.S. Sen. Frank Lautenberg in January, the U.S. Fish and Wildlife Service estimated a total of about 1.2 million bats had died across the East since 2007.

At least they listened!

[PYoungbaer]

And I thank them for that.