Monday, October 21, 2013

Even blogs can migrate

Monarch butterflies, caribou, dragonflies, hummingbirds, bats, and moths -- all of them can migrate and many of them do each year.  And, it turns out, even blogs can migrate.

Visit my new blog on my website

I created this blog to document my transformation from business executive to biologist, but I stopped updating it after I finished my master's degree and moved from San Francisco to Tennessee to work on my Ph.D.  Four years later, I've learned so much and had many adventures, catching bats in Texas and some tropical places, flying a Helikite, writing a book chapter, and even as a science advisor to the BBC's upcoming Cloud Lab expedition.  I recently put up a web site so that I could share more about my research, and my blog is migrating from this blogger site to the new web site.  Please join me there!  You can also now follow me on twitter as well.

Tuesday, July 20, 2010

Same bats, different state

These little beauties are Brazilian Freetailed bats, more scientifically known as Tadarida brasiliensis.  I took their picture recently in the early morning as they streamed back into their home at Frio Cave in southern Texas.  They were returning from a night of fine dining on corn earworms and whatever else was flying around way up there.  There are probably a couple million bats in that cave, but we only caught about a dozen of them, roughly half males and half females, and the females were all on their way to nurse their pups.

You might remember that this same bat represented most of the calls I recorded during my research in San Francisco.  I'm now working on my PhD at the University of Tennessee in Knoxville.  I'm interested in migration, and will be focused on insect and bat migration during the fall over southern Texas.  My advisor, Gary McCracken, and others have been working on these bats and the agricultural pests they consume for some time now, but most of that research has been focused during the spring migration and summer breeding season.  We think that the insects migrate south on the cold fronts that blow down off the plains as the summer ends, and the bats find those concentrations of insects and use them to fatten up for their own migration south to Mexico.  I'll be monitoring the bats and insects during September and October for the next few years in a variety of ways, looking for clues to explain exactly what is going on up there.  I hope to also include high-altitude acoustic recording with balloons, unmanned aircraft, and NEXRAD radar imaging in future field seasons.

Thursday, November 12, 2009

2009 bat meeting update

I'm back from my fifth annual bat meeting in Portland and here's my semi-regular update with the highlights. This picture is the lovely logo created for this year's meeting by Willy Gibonney.

First the bad news. Bats continue to be killed at wind turbines and wiped out by White Nose. I attended one session describing roosts in New Hampshire that were unaffected until last year, and then were almost completely wiped out in one year. This was the first time I actually cried during a scientific presentation. The situation is so grim that people are actually considering culling bats, that is proactively wiping out bats in caves in an attempt to contain the epidemic. Tom Hallam, a professor here at UT, gave a paper with mathematical models showing that culling would have no effect on the spread of the disease. So far White Nose has only been seen in the northeast, though it's probably already here in Tennessee, but we don't understand it well enough to predict how far south or west it will travel. From my understanding, it appears likely that the fungus is spread both by humans and by bats. So if you're a caver, please try not to go into caves until we have a better understanding of this terrible situation. The US government has just allocated 1.9M$ for research, which will help. According to the Fish & Wildlife service the latest information will be available here.

There was somewhat better news on the wind energy front. Ongoing research has shown that since bats are more active at lower wind speeds, when turbines aren't generating much income, the technique of "feathering" turbine blades does reduce bat mortality. Feathering means turning blades into the wind so they turn slowly. The sweet spot is evidently around 5 m/s of wind speed. Preliminary models show that turbines that are not "cut in" to the grid until winds are at 6.5 m/s during bat migration times would represent only about 1% of total annual revenue loss. You can read the report from Ed Arnett and others yourself. And kudos to Iberdrola Renewables for being so cooperative and supportive of this important research, unlike other wind energy companies.

Aaron Corcoran won the student paper competition with his ultra-cool report on tiger moths jamming bat sonar (videos here.) I also presented my master's thesis results in the student competition. Student presentations are all given on the first day of the conference, with no concurrent sessions, so the whole audience may be watching -- maybe 350 people or so. I was very nervous and since my talk wasn't until 4pm I couldn't really focus on the other student papers, although I remember Aaron's and a few others. Of course I did just fine and once I was finished I was able to enjoy the rest of the conference. It is a really great group of people, and after 5 years of this many of them are my friends. Attending NASBR is one of my favorite parts of the year. We were in Portland, so I also got to visit Powell's books for the first time, and go beer tasting at the Deschutes brewery. Next year will be in Denver. I hope you'll be able to join us!

Saturday, October 10, 2009

Be glad you're not a cave bat

If you care about bats, by now you have doubtless heard about the horrific White Nose Syndrome (WNS). This is a disease killing up to 90-100% of bats overwintering in caves throughout the northeastern US, and we believe it is probably here in Tennessee by now. The disease is apparently caused by a fungus, Geomyces destructans, that may have been somehow brought to the US from Europe. This fungus thrives in cold caves and gets into bats who hibernate there. The fungus or something related to it kills bats by causing them to burn energy they need to make it through the winter. It was originally found in 2006 in a cave in New York state and has been spreading disease-like from that epicenter with alarming speed. Bat biologists can't say exactly what, if anything, can be done to slow the speed of this nightmare but are scrambling to evaluate alternatives. The government has closed all caves in the area, but has no control over caves on private land. It's a huge sacrifice to ask cavers to stay out of caves, but if there's a chance that humans are involved in spreading the fungus, it seems worthwhile to steer clear at least until we understand more.

Someone asked me recently if I was going to change my plans and work on WNS instead of bat migration. My response is, for now at least, no. It's just too depressing. I'm excited about some work my advisor has started looking at high-altitude foraging of Mexican Freetail bats as they track insect migrations and prepare for their own southward migrations in the fall. But it's too early to say what my research proposal will end up including.

For now, I've got enough on my plate just adjusting to life in Knoxville, keeping up with the core curriculum for newly entering graduate students, and learning the ropes of being a teacher myself. I managed to escape any teaching duties in San Francisco, but here I'm a TA for two sections of Bio 130, the introductory biology class for biology majors, covering biodiversity and topics such as ecology and evolution. The old saying that the best way to learn something is to teach it turns out to be true. It's kind of fun to have that captive audience of young, impressionable minds, and to see what kind of a difference I can make for them. The first step was to ban all cell phone usage of course.

The academic life here is every bit as intellectually challenging and satisfying as I had hoped. We spend time sitting around discussing topics such as "what is a species, anyway" and reading Darwin. Friday afternoons there's a seminar presentation by one of the faculty or some invited scholar, and most of the department turns out and then heads down afterward to the local pub to carry on the conversation. There are politics and gossip, of course, but it doesn't seem to be out of control. My education from San Francisco State gave me a solid foundation from which to follow most of the debates, for which I am very grateful.

Certainly, I miss my friends, and San Francisco, and familiar culture and climate. Adjusting to the move has been a larger challenge than I expected, in part due to some unexpected family tragedy just before I moved. But I am committed to this adventure and game to see where this leads me.

Thursday, August 20, 2009

Bats of San Francisco: the answers

After much hard work, I finally managed to complete my master's degree at San Francisco State University this summer. At this point, I know more about the bats that live in San Francisco than anyone else in the world.
If you've had the patience to follow along you will know that my study involved an acoustic survey of the bats that live here in the city, to understand what factors affect their foraging for insects. Here's what I learned. There are at least four species of bats in the city. By far (84%) most of them are Mexican Freetailed bats (Tadarida brasiliensis ). Parks that have water in them also tended to have Yuma Myotis bats (Myotis yumanensis ). The two other bats I found were Western Red bat (Lasiurus blossevillii) and Little Brown bat (Myotis lucifugus). Bats are present and active all year in the city, with the highest activity levels in the fall. I found Freetailed bats in every place I looked, even in back yards. This is probably because they tend to fly high and forage over large distances, and their loud calls are easy to pick up on a recording. Yuma bats are known for hanging out near water, so it wasn't a surprise to find them near lakes and streams. However, they were not at all the lakes: I didn't find them at my recording location in Golden Gate park, at Stowe lake. Red bats migrate through in spring and fall but are known to over-winter in the arboretum in Golden Gate park. Little browns are the bat apparently most affected by white nose syndrome in the eastern US. They are really widespread and common, but I only found them in two locations: Pine Lake and the Fire Department's reservoir at the top of Twin Peaks.
The highest diversity of bat species were at those two locations. This is interesting because these are not large bodies of water, nor are they in large parks. Pine Lake, shown here, is in a medium-sized park with heavy recreational use. I considered five potential factors to explain this: park size, amount of tree edge in each park (where bugs like to hang out), distance to the nearest large park, distance to the nearest fresh water, and amount of native plants in each park. I used statistical modeling to understand what variables best explain the difference in number of species, as well as the difference in activity between the parks. The best explanation for the number of species was a combination of the amount of tree edge and the distance to the nearest water.
One interesting thing I didn't find was Big Brown bats (Eptesicus fuscus ). These are very common and widespread, especially in urban areas. I am not sure why I didn't find any in San Francisco, as they've been found in nearby areas.
You can read more about the gory details of my research in my thesis (pdf download). If you have questions about it please send me an email at jennifer at krauel dot com.

Friday, April 17, 2009

My 15 minutes of Internet fame

I know, I know, you have been eagerly waiting for an update on my PhD plans. But first, I have to tell you that one of my bat photos appeared recently on my favorite web site, Cute Overload. This is one I took last summer while working down in the Caribbean. I guess the combination of a cute fuzzy animal butt ("tock" in CO lingo) plus the whole concept of a bag full of bats was enough to get selected. You can see more about bags of bats here and here.

And for my PhD destination, the winner is... Tennessee! I was very impressed with the faculty and other grad students when I visited there recently. I was lucky enough to get accepted there, one of the top schools in ecology and evolutionary biology. So I'll be moving to Knoxville this summer, and starting to study bat migration. But first, I have to finish that pesky master's thesis...

Sunday, March 22, 2009

Eavesdropping on Golden Gate Bats

I'm almost done with collecting data for my thesis! I have only one more park to do, which will hopefully happen tonight if this storm passes today. I've recorded one night per quarter in each of 21 parks in the city. So far I've found four different species. Still to come: completing the analysis of this round's calls, doing the statistical analysis of my results, and then writing it up. I'm hoping to get everything together by the end of this month, so I can spend April writing, and schedule my thesis defense for mid-May.

I do have news on the PhD application front, but I'll post about that soon. The good news is I got accepted to at least one school for next fall.

In this picture, my detector rig sits in the tree in the foreground, aimed out over Stowe Lake in Golden Gate park. I haven't looked at the files I just got, but in the past I've had hundreds of Mexican Freetail calls, and a few Yuma Myotis calls from this location.