Animal Flight Lab on Bat Conference, Prague

Members of the Animal Flight Lab are currently attending the 15^th International Bat Research Conference in Prague. This is the main outlet for bat science, being the biggest assemblage of bat scientists ever at 550 individuals. In the afternoon on Monday (23 August) we had the flight symposium, organised by Anders H and Sharon Swartz, Brown University. Members of both the Lund and Brown labs gave excellent presentations, showing how kinematics and PIV data could be used to get lots of information (Florian Muijres and Rhea von Busse). Other talks were on flight mechanical constraints on bat size (Ulla Lindhe Norberg), context-dependent flight speeds (Marc Holderied), energetics by Na-Bicarbonate isotope analysis (Christian Voigt), and muscle and tendon morphology in the wings (Sharon Swartz). In the evening, the whole group of speakers went in to Prague for a excellent dinner at a restaurant (Café du Paris, see picture). After dinner we strolled through central Prague and into the old city. Today (Tuesday, 24 August) we have enjoyed many more interesting talks, and soon we will attend the poster session, where Melanie Stuiver will present her poster on the bat robot (RoBat).

News on power curves

Summer is coming to an end and we have an autumn of activities to look forward to. As a starter, I would like to recommend a series of papers just out in the J Exp Biol, in which the mechanical power was measured in cockatiels. In three papers the researchers measured muscle work, compared muscle work with output from a aerodynamic model, and finally measure the flight metabolic rate to get conversion efficiency. The papers discuss all the difficulties and pitfalls, we are so well aware of, but they constitute a good and recent update on the subject. It is concluded that power consumption during flight must come from more than just the main flight muscles (Pectoralis major/supracoracoideus), otherwise the efficiency must be extremely low in the order of 10%, or so.

California Dreamin'

Today the great news reached us that Marta (Wolf) has received a prestigious postdoc stipend from the Swedish Research Council. This is an outgoing postdoc for Marta to work in Robert Dudley's lab, University of California, Berkeley. There, she will study the evolution of flight in insects, and we now look forward to hear reports from her research and Californian experience.

Congratulations Marta!

New paper on LEV

In a new paper by Tatjana Hubel and Ca Tropea published in J Exp Biol, the occurence of LEV in model wings is investigated. The wings are large, goose size, and the kinematics resemble that of a large bird as well. Still, these wings develop LEVs associated with a delayed stall. These results suggest that even relatively simple kinematics of forward flight in largish birds are potent in developing non-ignorable LEVs associated with unsteady aerodynamic effects. The authors also raise the question whether the quasi-steady approach to bird flight, as adopted in the most popular flight models, perhaps now should be reconsider. I anticipate we will need to discuss this in the near future.

New Lab Publication

It was recently demonstrated that shorebirds (godwits) fly non-stop between Alaska and New Zealand on their autumn migration - a flight that takes more than a week! Do we need to revise our current flight models as a result of these observations? How did such long flights evolve? These, and other questions are discussed in an "unsolved mystery" piece in the May issue of PLoS Biology: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1000362

New lab publication

Two members of the AFL and their co-authors have written a paper titled, 'Grand Challenges in Migration Biology', which was published online in the journal Integrative and Comparative Biology today. The paper grew out of the symposium on Integrative Migration Biology that A.H. and M.S.B. attended in January.

The paper can be found on the 'advance access' portion of ICB's website, here: http://icb.oxfordjournals.org/cgi/reprint/icq013 .

DelFly makes it into the Lund Wind Tunnel

On Friday 9 April, last week, the dutch MAV experts B. W. van Oudheusden and Bart Remes from the TU Delft visited Lund and the Animal Flight Lab. The reason for their visit was discussion about Melanie Stuiver's MAV design. The dutch lab develops some famous MAVs, such as the DelFly, which is inspired by insect flyers such as dragonflies (and uses a clap-and-fling mechanism), and the Roboswift, which is inspired by the morphing wings of real swifts. As a proof of concept the DelFly was tested in the wind tunnel, with medium success. It turned out to be somewhat hard to control it's flight in the tunnel, but after some practice pilot Bart Remes could keep the fly stationary in the test section at a speed about 2 m/s.