Animal Flight Lab

New publication in French Academy journal

2012-02-02T13:21:00.003+01:00

In a new paper published in the French Academy of Science journal, Comptes Rendus Mechanique, members of the Lund Animal Flight Lab has published a paper about a bat-inspired flapper (see figure). The paper is entitled "Stroke plane angle controls leading edge vortex in a bat-inspired flapper", This is an attempt to mimic the flight of a true bat, and how a wing composed of a compliant membranous surface function. The advantage of working with a flapper is that it can be programmed to move its wings in all possible ways, i.e. also in ways that live bats usually don't do, and so the whole kinematic parameter space can be explored. The drawback is of course ,as with all models, to know how much the model depart in performance from the real system and if it matters. The current paper describes the development of a leading edge vortex (LEV) during the downstroke, which is an important aerodynamic ingredient of slow bat flight. The LEV dynamics was partially controlled by the stroke plane angle. A copy of the paper can be obtain my mailing (anders.hedenstrom@biol.lu.se)

The Dickinson lab website in new dress

2012-01-20T16:26:00.005+01:00

Browsing around I recently found that the Dickinson lab, where AFL memeber Florian Muijres now is a postdoc, has a new look. The old classic version can still be accessed, while the new lab website "FlyRanch" demarcates the move by this lab from CalTech, Los Angeles, to University of Washington, Seattle. The webiste shows the great range of research done by this lab. Have a look and get impressed. The lab members are assigned different characters and characteristics of typical fantasy literature creatures. The leader of the clan, overlord Michael himself is "ruthless and fearless"! Now we look forward to see which character Florian will assume.

A new paper in Current Biology from FlyRanch deals with polarized light perception in fruit flies, and could be consulted as a typical contribution.

Climate change affects flight speed in wandering albatrosses

2012-01-17T19:43:00.005+01:00

A new study published in the current issue of Science reports about climate change related effects in flight behavior in wandering albatrosses, breeding on Crozet Islands in the southern Indian Ocean. Due to climate change related phenomena the mean wind speed has increased in the southern oceans, between 50 and 60 S. Albatrosses use dynamic soaring, which is a way of extracting energy by soaring in the wind gradient in the boundary layer of the sea. The stronger the wind, the faster the albatrosses can fly. A french team, lead by Henri Weimerskirch, has studied wandering albatrosses on the Crozet Islands during 20 years. During this period the winds have increased, and the scientists have been able to measure related properties in the albatrosses. The albatrosses now forage further to the south, their flight speed has increased from 10 to 12 m/s, and their daily travel rate during foraging journeys has increased from 500 to 700 km/day. Better foraging success has led to improved breeding success, and the albatrosses have increased by about 1 kg in body mass. It seems as if we here have a positive effect related to the ongoing climate change, but the scientists mention that the predicted scenario of wind change will come to a deterioration further down the trail, so the observed effects may be temporary. It is very nice, though, to see a study reporting an association between climate change and flight speed.

Span efficiency of desert locusts

2012-01-13T13:33:00.003+01:00

In a new paper, AFL-postdoc Per Henningsson, now working in the flight group at Oxford University, and Richard Bomphry have published a paper about "Time-varying span efficiency through the wingbeat of desert locusts" in the journal Interface. They use time-resolved PIV to work out the span efficiency, which is something that we have tried also in Lund. In a previous paper Richard Bomphrey had estimated that span-efficiency is 0.89 at mid-downstroke in the locust. The Oxford Group uses a slightly different calculation method that is customary in Lund, and so we will read this paper for our next lab meeting. The question is how much the difference in method matters to the final result, if it matters at all. It is nice to see the spread of PIV in the animal flight research community, and there are certainly still lots of research needed to be done. The answer, by the way, was 0.79.

New paper about aerodynamics in slow-flying flycatcher

2012-01-05T11:53:00.005+01:00

Just of the press from the Journal of the Royal Society Interface is a paper about pied flycatcher aerodynamics, by aouthors Florian Muijres, Melissa Bowlin, Christoffer Johansson and Anders Hedenström. Stereo flow-visualization was used to study the wake vortices shed off the wings of flycatchers as they flew slowly in the wind tunnel. The results sow that the aerodynamic force is mainly from the downstroke, resulting in a closed vortex loop. The results also show that the tail is involved in deflecting the downwash, resulting in an aerodynamic efficiency comparable to that of cruising flight. During the upstroke the wings generate no significant forces, but the body-tail configuration does to some degree, and so the upstroke phase of slow flight is not completely uninteresting from an aerodynamics viewpoint.

Old and New Activities within Animal Flight Lab

2012-01-04T11:57:00.003+01:00

First of all, a happy new year to AFL members and followers. At the transition between years one usually contemplates what has happened during the past year, and what will happen in the year to come, in the present case 2012. Last year, 2011, was a really productive year in the AFL, with Florian Muijres dissertation in April being a local peak. For the occasion Tom Daniel visited as opponent and we all had a great time. Now Florian and family has already arrived in Seattle, where Florian will make a postdoc with Michael Dickinson. We wish them the best of luck and look forward to get regular progress reports. During the autumn, postdoc Sophia Engel, Germany, left after a 2-year period here. Master student Gide Koekkoek, The Netherlands, finished his project on the bat flapper before the summer, and just after Christmas the corrected proofs of a paper was sent back to the journal. Another master student was Naid Mubalegh, France, who did a project on zebra finch flight during the spring. Here in Lund, we welcome Jonas Håkansson as a new PhD student. Last year we received an infrastructure grant that we are currently trying to spend, and hopefully the new equipment will serve us well in the wind tunnel. Finally, a reading tip in the form of a JEB paper about immune function decrease immediately after endurance flights in starlings. The picture is from our pre-christmas lab celebrations, with the hope we get reasons to celebrate many more times during 2012!

Lucia at animal flight lab

2011-12-14T10:50:00.008+01:00

Lucia is celebrated each year on 13th December, with a choir consisting of Lucia herself (wearing candles in the hair), terns, staffans, nomes and other creatures. This year Lucia did not show up at the Biology Department, but the traditional beverages and ginger cookies were consumed as usual. Also members of the flight lab participated in the celebrations, taking a break from a brain-storming activity during the weekly lab-meeting. What should we like a new PIV-system to do for us? - that is the question.

CAnMove 2nd conference

2011-12-07T15:37:00.002+01:00

During two days members of CAnMove have attanded the 2nd conference, whith invited talks given by various canmovians, including PhD-students, postdocs, seniors and two members of the Scientific Advisory Board. Marilyn Ramenofsky talked about her work on physiological adaptations to the annual cycles, using two populations the white-crowned sparrow, while Steven Reppert gave an overview about his lab's work monarch butterfly migration (see picture). The Animal Flight lab was well represented and gave two presentations (Christoffer and Anders). During the conference we also discussed how to further improve the activities within CAnMove, and how to facilitate even better research. It was a great meeting and now we just have to dig into it and move forward!

CAnMove 2nd conference

2011-12-07T15:30:00.002+01:00

Prestigious postdoc to Florian Muijres

2011-11-25T09:12:00.003+01:00

We are very happy that animal flight lab member Florian Muijres receievd 2-year postdoc from VR (The Swedish Research Council). These postdocs are awarded in severe competition and allows the recipient to spend 2 years abroad. Florian will now go to the University of Washington, Seattle, USA, where he will work in Michael Dickinson's lab. We wish all the well for Florian's postdoctoral stay, but we also hope there is a chance that we will see him again in Lund, as these postdocs usually come with a return-funding. But now we look forward to see what interesting questions Florian will investigate in the big country to the left of the Atlantic. Congratulations, and all the best of luck!

New birds to the wind tunnel

2011-11-21T11:14:00.003+01:00

During the weekend two new birds, Diamond doves, moved in to the wind tunnel aviary. The hope is that they will learn to fly in the wind tunnel and that we will be able to find something interesting out from these flights. These are small doves living in arid habitats of Australia in the wild, while they have become popular pet-animals because they easily reproduce in captivity. Hopefully these pigeons will be flying in the wind tunnel soon, and allow us to study the wing-beat kinematics, the wake of flapping and maybe also gliding flight. Stay tuned and you will soon hear more about this!

Hovering in a whiteye

2011-11-11T15:06:00.002+01:00

A research team based in Taiwan has published a new PIV-study on the hovering aerodynamics in hovering Zosterops japonicus, which birdwatchers know as whiteyes. These 6-7 g birds are capable of hovering, i.e. flying at zero forward speed, which was studied in a special hovering chamber. Wing kinematics and induced vortex flows were monitored, which uncovered a new mechanism for enhancing lift force in hovering in birds - a ventral clap-and-fling. This mechanism is known from some insects already since the dane Torkel Weis-Fogh's pioneering work, but had not been observed in birds before. Interestingly some of the high-lift mechanism previously known from insect flight are now being observed in birds and bats, mainly due to the application of the PIV-technique to animal flight. We, the Lund crew, are happy to see this approach spreading to other labs studying animal flight. The paper can be found in Experiments in Fluids.

Migration Ecology Course for PhD students

2011-10-19T11:40:00.002+02:00

The biannual course in migration ecology at Lund University started yesterday. After an introduction the students give short, 15 min, presentations about their projects during the first two days. Then, the first lecture day starts as usual with locomotion. This years line-up is Colin Pennycuick, Anders Hedenström, Florian Muijres and Christoffer Johansson. As before we focus on animal flight and swimming. There is also an exercise involving the measurement of aerodynamic morphology and using it to calculate various performance measures using Colin Pennycuick's progrom Flight. This course is a great experience for both students and lecturers. For more information about the program have a look at www.canmove.se.

New research on bats

2011-09-30T09:43:00.004+02:00

During this week two interesting papers on bat biology have been published. First, McGuire et al (J. Anim. Ecol. doi: 10.1111/j.1365-2656.2011.01012.x) reports on radio tracked silver-haired bats at Long Point Bird Observatory, Ontario, Canada, Radio tagged birds were tracked using 5 towers with antennas. Most bats stopped over for 1-2 days before continuing migration, while some bats stayed for up to two weeks. Another paper, by Elemans et al (Science, Vol. 333: 1885-1888) reports about ultra-fast laryngeal muscles, which can produce echolocation calls at rates beyond 160 calls per second. Bats use such fast repetition rates during their final approach to a prey, calls known as feeding buzzes that are heard in a bat detector.

New Animal FLight Lab website

2011-09-27T12:06:00.003+02:00

The Animal Flight Lab at Lund University proudly presents its new website. We have updated the content, both when it comes to members of the lab, current projects and new publications. There have been some changes in recent time. Marco Klein Heerenbrink has started as PhD-student, and will explore aerodynamics of gliding flight further anyone else before. Sophia Engel, who has been a CAnMove funded postdoc for two years, left last Sunday for southern Germany. During her time here, Sophia has made a number of wind tunnel experiments on insects and some very extensive field experiments on flight performance in damselflies. There are now plenty of data to analyze and write up. At todays lab meeting it was decided that, in addition to the newest research papers, we will also start reading the 'classics' in the field of animal flight.

Textbook about bats

2011-09-19T17:24:00.003+02:00

It is time to activate this blog again, a semester and a new lab meetings ahead. We, the Animal Flight Lab at Lund University, will have weekly lab meetings on Tuesday mornings at 09:00, where we discuss a recent paper and other lab businesses. We look forward to a very active autumn, and we especially welcome Christoffer back from a paternal leave! It is a pleasure to note that there is a brand new edition of John Altringham's book "Bats: from evolution to conservation" (Oxford), where the flight section has been updated to include some Lund results on bat wakes. We appreciate this since the current view on bat wakes has changed quite dramatically in recent years due to those experiments, which have also been confirmed by experiments at Brown University. So, we finally made it into the textbook lore!

Please also note that the lab is looking for a new PhD student (see advertisement at the links below, in Swedish and English, respectively).

http://www.lu.se/o.o.i.s?id=22598&Dnr=419462&Type=S

http://www.lunduniversity.lu.se/o.o.i.s?id=24914&Dnr=419462&Type=EU

New PhD thesis from Animal Flight Lab

2011-04-06T22:30:00.004+02:00

Florian Muijres has received his thesis from the printer and is busy distributing them. The thesis contains seven different studies about aerodynamic performance in bats and birds. Two papers describe a high lift mechanism - Leading Edge Vortex - used by bats and pied flycatchers when flying slowly. This vortex enhances lift by 40% or more in these vertebrates, and before Florians work it was thought to be a typical insect mechanism. In other papers time-resolved PIV is used to work out aerodynamic efficiency of bats and birds, and to evaluate an adaptation of the classic actuator concept of flapping flight. Florian is to be congratulated to marvelous thesis, which is not only interesting on the inside but also beautiful on the outside. The public defense will take place on 28 April at 10:00 am, in the Blue Lecture Hall, Ecology Building, Lund. As faculty opponent we are very glad to welcome Professor Tom Daniel, University of Washington, Seattle.

New paper about bat aerodynamics from Animal Flight Lab

2011-03-03T21:15:00.009+01:00

A new paper, entitled Comparative aerodynamic performance of flapping flight in two bat species using time-resolved wake visualization from the lab was published today in the Journal of the Royal Society Interface, in which Florian Muijres and co-workers compare two species of bat with regard to their aerodynamic performance. Florian has developed very detailed methods for analyzing the wake properties, as recorded by time-resolved stereo PIV in the Lund University wind tunnel. The two species being compared, Glossophaga soricina and Leptopnycteris yerbabuenae, differ with a factor of 2 in mass and in some ecological respects. The Leptonycteris is a migrant while the Glossophaga is a resident, while they are both fruigivores that eat/drink nectar from plants using hovering flight. A measure of flight economics, the maximum lift to drag, was similar between the species, but it occurred at a higher speed in the larger species. This could reflect different performance optima between the two species associated with requirements for slow flight in Glossophaga and cruising/migratory flight in Leptonycteris. The wake geometry showed the typical bat features in both species, including reversed vortex loops at the transition between up-/downstroke and vortices shed from the wing roots.

Animal Flight Research Highlighted in Research Council Annual Report

2011-02-28T11:21:00.005+01:00

In the current "Annual Report for 2010" from the Swedish Research Council (VR), our research on animal flight was selected to illustrate "basic research of the highest quality", which is an investment in the future. It's very nice to be appreciated in this way, I think, by our main funding body and we should see that as a token of achieved quality and visibility. There is also some accompanying text on VR:s website, with answers to some questions about the research. The picture on the left was taken earlier this winter, when AH was performing some critical experiments.

Rhea gets PhD

2011-02-14T15:26:00.002+01:00

On last Friday our group member Rhea von Busse passed her oral examination for a PhD at the Humboldt University, Berlin. Dr Busses thesis is about "The trinity of energy conservation: kinematics, aerodynamics and energetics of the lesser long-nosed bat (Leptonycteris yerbabuenae)", including chapters on kinematcs, aerodynamics (wakes), a comparison between kinematics and wakes, and an investigation about the flight metabolic rate. This thesis is the result of the collaboration between AFL and York Winter. The discussions leading up to this collaboration were initiated some 10 years ago, when AH visited the Max Planck Institute at Seewiesen to give a talk about the wind tunnel studies on birds that were underway. Then Rhea came with the first batch of Glossophaga soricinas used for our first studies (and Rheas master thesis). We congratulate Rhea to this magnificent achievement and wish her the best of luck with her new studies on bats in the Brown University bat biology group.

New wind tunnel at Western Ontario

2011-01-28T09:11:00.004+01:00

In a NewsFocus piece in Science entitled "Treading Air", the new hypobaric wind tunnel at the University of Western Ontario is described. In this wind tunnel the temperature, air pressure and humidity can be controlled. This tunnel is therefore ideal for studying physiology during flight in way not possible in other wind tunnels. This tunnel is also equipped with a PIV-system, and the article tells that airflow around the wing-tips of a starling has been studied. We wish our wind tunnel colleagues at Western Ontario, led by Chris Guglielmo (see image), the best of luck with their wind tunnel and look forward to see their first results published soon.

Nature-inspired flight

2010-12-07T22:04:00.002+01:00

In a new issue of the journal Bioinspiration & Biomimntics, a special section is devoted to nature-inspired flight. There is an emphasis on MAVs of various sorts, but also purely animal flight papers have been included. The issue has been edited by two well-known figures in our field, David Lentink and Andy Biewener. The latter is handling most of our mansucripts submitted to JEB. The two editors write an introductory essay, following by the original papers. Have a look here. There will be reason to return to these papers.

Operation snow storm: lab meeting

2010-11-29T14:39:00.005+01:00

During the lab meeting today (29 November 2010) the AFL-members that made it to the Ecology Building, in spite of the snow-storm, discussed the recent paper about “The effect of body size on the wing movements of pteropodid bats, with insights into thrust and lift production”. This paper, from the Brown University Group, reports on kinematic parameters studied in six species of bats. The paper concludes that “the ways that bats modulate their wing kinematics to produce thrust and lift over the course of a wing beat cycle are independent of body size”. How convenient if this proves to be true! The authors however thinks that small bats, such as Phyllostomids, may differ from the medium to large sized bats studied here. One reason put forward could be that small bats, using a leading edge vortex, are more insect-like in their use of aerodynamic mechanism, and therefore different from other bats. It will be interesting to find out of smaller species of bats differ in flight.

2010-10-04T11:56:00.003+02:00

A new paper on bat flight has now been published by the Brown University group in the Journal of Experimental Biology (Hubel et al. 2010), where they report on the wake dynamics in a medium sized bat, Cynopterus brachyotis, when it is flying at intermediate speeds (5 and 6.7 m/s). The wake is very similar to that found for other bat species studied in Lund, which lend support for the notion of the generality of these results. Hence, it is very nice to see results of bat aerodynamics being confirmed by anther lab. Since papers of bat flight are still quite rare, this paper will be the focus of our next lab meeting, which will be Monday 11 October, 2010.

Melissa is back in the US

2010-09-13T11:40:00.002+02:00

As the remaining AFL crue has noticed Melissa Bowlin has left Lund after 2 years here as Marie Curie postdoc fellow. It has been two years of intense work, including wind tunnel experiments, writing of book chapters, conferences and symposia. Melissa left with lots of data still to be analyzed and published, perhaps most notably about the effect of moult gaps on flight performance in passerine birds. Melissa has now taken up a new position as assistant professor at Dearborn, Detroit, where she is teaching animal physiology alongside her own research. We wish her all the success in her new position in the US, but also that we will remain in close contact in the future.

MAVs navigating without GPS

2010-09-03T11:01:00.004+02:00

Engineers at MIT has built a MAV that is able to navigate inside a complicated environment, where GPS navigation is denied. The vehicle is perhaps mainly interesting for its navigations skills rather than it's flight performance. The MAV has a laser scanning the environment to build up an image about the surrounding topology. At the recent International Bat Research Conference in Prague, there were talks about using sonar systems similar to those of bats to navigate the environment. The real challenge will be to combine any of these navigation based systems with a MAV that uses flapping flight, and flies like a bat or an insect. A film showing the MAV flying indoors can be seen by clicking here. The accompanying paper is not very new, published in Science in late 2009.

Animal Flight Lab on Bat Conference, Prague

2010-08-24T18:53:00.004+02:00

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

2010-08-18T11:16:00.004+02:00

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'

2010-05-28T15:19:00.002+02:00

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

2010-05-18T13:49:00.005+02:00

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

2010-05-04T22:57:00.004+02:00

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

2010-04-22T16:26:00.002+02:00

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

2010-04-15T17:44:00.002+02:00

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.

Rhea gets FAZIT stipend

2010-03-29T15:17:00.002+02:00

AFL member Rhea von Busse has received a FAZIT stipend, which is a foundation of the FAZ (Frankfurter Allgemeine Zeitung), which is one of the biggest, reputable German newspapers. They are mainly known to support Journalists in their career but they also support scientific research by giving stipends to doctoral and postdoctoral candidates. Rhea says "I didn’t even know that they provide PhD stipends, but one of the grant counselors at my University told me to apply there and don’t feel discouraged by their guidelines, which mostly address Journalists.". Rhea has collected all of her data to finnish her PhD thesis, and now "only" has to analyze those and write up some manuscript.

Congratulations to Rhea!

Bat ecology on SVT Play

2010-03-16T22:07:00.002+01:00

Yesterday, monday 15 March, SVT sent a nature film following a group of Germans and US scientists working with bats on Barro Colorado, Panama. This rater small island holds 72 species of bats and one main question addressed by these biologists is: how can they co-exist in such a small area. The answer is multi-faceted, including roost sites, food type and flight/foraging altitude. We can see the biologists catching bats, filming them in infrared, recording their sounds and making experiments. Even if the film is narrated in Swedish (could be a good practice for those who are still learning swedish), the scientists themselves speak in english. I liked the film and strongly recommend it to everybody in AFL. It can bee seen at

http://svtplay.se/v/1926696/naturfilm/fladdermossens_paradis

Rabies in Swedish bats

2010-03-12T09:05:00.004+01:00

Bats can get infected about a form of rabies (Lyssa virus), which rarely also can be transferred to other mammals, including Homo sapiens. Out of four fatal cases in Europe during the last few decades two have been bat researchers, so there is a small risk of handling wild bats in Europe. However, Sweden has thus far been without any reported cases of rabid bats. But new samples taken during 2009 in Skåne found antibodies against bat rabies in eight Daubenton's bats (Myotis daubentoni), according to a press release yesterday. These bats are non-migratory (at least we think so), and therefore they should have been in contact with actually sick bats at some stage. Hence, Sweden is no longer a rabies-free territory. But this is a fully expected result considering that rabies is found in our neighboring countries Denmark and Finland, and is common in Germany and Poland. Since many bats migrate to continental Europe it would have been strange if infected bats never turned up in Sweden. This new finding does not change any of the official recommendations for us working with bats, which include being vaccinated and wearing a glove when handling (such as ringing) bats. More information can be found at www.naturvardsverket.se/fladdermus .

To stay or to go?

2010-02-25T15:04:00.009+01:00

Especially during a winter like this those birds that migrated south last autumn probably did a good choice in a Darwinian sense. In mild winters, however, those that decide to stay near their breeding areas may be at an advantage because they can select territories first and they don't have to pay the cost of migrating. Many bats have evolved the alternative strategy of hibernating, which means that they lower their body temperature almost to the ambient, and therefore they spend very little energy. But there is an energy cost and the fat they accumulate in the autumn must last until spring, when insects emerge again. In that sense they can be compared with bird migrants, but instead of converting fuel into distance, they migrate in time. In bats, there are species that do migrate, often in combination with hibernation at the winter destination, and we may think about how this strategy came to be? Here, I want to share some images from a recent winter bat count in the mine at Taberg, Småland. Six species were encountered, and here are pictures (lower) of Whiskered bat (Myotis mystacinus; the two small ones) and Brandt's bat (M. brandtii; the two larger ones on the right), and the picture on top shows a Natterer's bat (M. nattereri), which is quite a rare species in Sweden.

Party in Animal Flight Lab

2010-01-29T16:08:00.005+01:00

Congratulations to Per Henningsson on his thesis defense on 29 January. With opponent Bret Tobalske we witnessed a very interesting discussion about bird flight, and swift flight in particular. Now we are looking forward to a great party tonight, and wish Dr Per a successful postdoc and career! The red-flanked blue tail Tarsiger cyanurus shown her to the right is Per's latest acquisition on his Swedish list. Congratulations also to that!

New thesis: flight of swifts

2010-01-25T15:42:00.003+01:00

On Friday 29th January 2010, Per Henningsson is defending his thesis on "fluid dynamics, flight performance and flight behavior of common swifts". The defense takes place in the Blue lecture hall at 10:00, with Prof. Bret Tobalske as faculty opponent. On the day before, you can enjoy an extra CAnMove mini-sympoium on the animal flight, starting at 14:00 in the seminar room "Tanken", in which Bret Tobalske will talk on his fascinating research on hummingbird flight. That the swift is a remarkable bird is perhaps not new to most of us, and Per is now getting some well deserved media attention for his spectacular PhD thesis. See e.g. http://www.gp.se/nyheter/sverige/1.296297-flygexpertens-hemlighet-avslojad ).

Looking forward to a great week

2010-01-20T15:58:00.003+01:00

As for our next lab meeting on Monday 25th January (2010) we will join forces with the Svensson lab. Time is our usual at 09:00, and location is also the usual (Argumentet). We will discuss some relevant insect flight papers that Sophia will distribute.

It should also be mentioned that Melissa Bowlin has accepted a faculty position at the University of Michigan Dearborn, and we wish her all the best of luck there. But before that Melissa will be with us until August to finish lots of interesting projects.

Next week is going to be eventful in other respects as well. On Thursday at 14:00 we will have a mini symposium on the aerodynamics of flight. Main speaker is Dr. Bret Tobalske (see image), University of Montana, who will talk on hummingbird flight, with a few other talks from AFL reps. Bret Tobalske is here also to act as faculty opponent on Per Henningsson's thesis defense, taking place on Friday 29 January at 10:00, Blue Lecture Hall.

Animal flight lab in Seattle

2010-01-08T01:01:00.003+01:00

Greetings from Seattle! The Space Needle and the mountains looked on as two members of the flight lab, Anders and Melissa, gave talks at this year's SICB meeting. Melissa (who is currently talking about herself in third person) introduced the Integrative Migration Biology symposium she had organized, and Anders spoke about mixing theory and wind tunnels to increase our understanding of animal migration.

The symposium went very well, down to a last-minute replacement talk by Ken Lohmann for Tom Kunz, who was ill and couldn't attend the conference. A Science reporter was at the event speaking to several of the speakers, and we were approached about potentially writing a book (something that, if it happens, won't be happening anytime soon!).

There were many interesting flight talks, but since many of them were at the same time as the migration session, I didn't get to see them. Hopefully Anders did and he can fill you all in on all of the exciting research going on in the US. I personally got to meet up with old lab-mates and friends, and generally enjoyed the area (including some wonderfully fresh seafood!).

Pre-conditioned flash lamps in place

2009-11-30T18:05:00.004+01:00

As for the replacement from old to new flash lamps in the PIV laser, we now had a third batch of lamps to install. Replacing these lamps is a risky business for various reasons, not only the need of climbing the tunnel but also the actual replacing these delicate (easy to break) filaments. And when the fourth (final) lamp was to be inserted - i broke! A word signaling a problem was heard from the tunnel top and it was immediately clear that something had gone wrong. Immediately checking with Litron people, however gave some hope in that it might work with one of the non-conditioned lamps in tandem with a pre-conditioned one. Some more work and then a final test - it worked. So, now we have a laser with a complete set of flash lamps. We now only have to align the thing to optimize the set-up for maximum power output.

PIV laser gets new flash lamps

2009-11-07T17:58:00.006+01:00

As the laser has lately given only about 25 mJ per pulse when set to maximum power, we figured it is perhaps time to change the flash lamps. In our Litron laser there are 4 lamps to replace, and on Friday afternoon we had everything in place, i.e. the lamps, new o-rings, appropriate laser manual and isopropyl alcohol to clean the new lamps. It took some time, and even if the manual explicitly said "do not lose" about 4 particular 3M bolts that was exactly what happened to one of them. It fell to the floor, two bounces was heard and then it was gone, probably it fell to the basement. The lost bolt must have moved a horizontal distance of at least 1 m, while subsequent experiments with a similar bolt showed an average horizontal displacement from the position of first floor contact of about 15 cm! However, we found new stainless steel 3M bolts and could proceed as planned. Also cooling water was renewed and before that we had changed to new filters. So, no we will hopefully get back the strong and clear light sheet that make stereo PIV such a nice method.

New Lab meeting procedures

2009-10-14T15:39:00.005+02:00

As we have agreed we will try a new strategy regarding our lab meetings, by having one meeting every week, starting at 09:00 Monday. The place will be the seminar room "Argumentet". In this way we can keep ourselves more informed and it should facilitate co-ordination of wind tunnel activities during the rest of the week. So, this new system will begin next Monday, 19 October, and I have also selected a paper for us to read until then. The paper is "Flapping wing flight can save aerodynamic power compared to steady flight" by Umberto Pesavento and Jane Wang. It appears in Physical Review Letters, which is the tabloid equal for physical sciences.

New Lab Publication in J Exp Biol

2009-10-06T17:23:00.004+02:00

In a new paper, published in J Exp Biol 212: 3365-3376 (2009), Christoffer Johansson and Anders Hedenström report on wake properties of blackcaps (Sylvia atricapilla) studied on the Lund University wind tunnel. They use a high speed stereo-3D PIV system to get information from the entire wake behind the flying bird. It was found that the wake geometry was slightly more complicated that previously thought about passerine birds. This is mainly due to that the PIV system used is capable of detecting more subtle features of the wake, than with previous 2D visualization. Another twist is that one bird accidentally molted its tail, but flying without a tail did not cause any dramatic changes as to the bird's wake. The function of the tail, whether it is a lift generating surface or if it works as a splitter plate that reduces the drag, remains unclear. New experiments will hopefully teach us more about what birds have tails for.

New Publication from Oxford Group

2009-09-22T12:11:00.006+02:00

In a new paper published in Science last week the Oxford group of animal flight, headed by Adrian Thomas, shows how important it is for a locust to have appropriate camber and wing twist to maintain the high performance achieved by insect wings. The way they do it is by using a CFD (computational Fluid Dynamics) model, and in a stepwise manner remove the camber and twist exhibited by the real locust. Before trusting the model output, the CFD model was validated against real data using smoke flow visualization and PIV measurements obtained from locusts tethered in the wind tunnel. In accompanying podcast Adrian explain certain problems they had in modeling the upstroke of the hind wings, so go an listen also for that.

Final symposium tally

2009-09-15T13:21:00.002+02:00

Abstract submission has closed for SICB's 2010 meeting, where we (Isabelle Bisson, Martin Wikelski, and I) will be holding our Integrative Migration Biology symposium. The way SICB organizes the meetings, the 13 symposium speakers (including Anders, Susanne and myself) are set, but people can apply to give a presentation in a coordinated session. The official numbers are in, and our symposium attracted more coordinated session speakers (24) than any other symposium this year! I can't wait to meet and talk with everyone who's coming; it sounds like there will be some great presentations.

You can still register for the meeting if you haven't already; it should be a lot of fun--and there are plenty of biomechanics talks for those of you who are less interested in migration than I am!

New Lab intern: Roel Vleugels

2009-09-15T11:25:00.003+02:00

During the autumn 2009 Roel Vleugels, a student of aeronautical engineering at Delft University, is visiting our lab as part of his master program. Roel is going to adapt our aerodynamic balance for precise measurements of aerodynamic forces on different wings, such as flat plates and the Eppler 387. He will also make measurements on the drag of a swift look-alike model bird body. We welcome Roel to the group and hopes he gets a great time while here!

New Fridge for the Wind tunnel

2009-09-01T15:54:00.003+02:00

A new fridge was delivered today, 1 September 2009, to be used for storing animal food for wind tunnel birds and bats. The fridge has a constant temperature facility, meaning it has a fan that mixes the air inside the fridge. The old fridge was broken since many years and in the interim a constant temperature box has been used, which accommodates fridge-like temperatures but is otherwise not large enough. The recent problems with the large generic cold rooms in the Ecology building, with measurable water depth on floor and mold infestations, made this acquisition a necessary step in order to be able to keep high quality mealworms, crickets, honey, and nectar plus at optimal conditions. The picture shows happy Florian Muijres and Melissa Bowlin during the installation procedure of the new fridge.

Aerodynamic wake behind a flying bat

2009-09-01T15:24:00.008+02:00

Here is a nice instructive video of the aerodynamic wake behind a flying bat. The bat species is Glossophaga soricina, and it has a forward flight speed of 4 m/s.

In the movie you see the flying bat from behind. The right side of the movie shows the right half of the bat body and its right wing, while the left side of the movie shows the wake generated by the flapping left wing. This wake is calculated using our DPIV system. The colors in it are vorticity strength while the black arrows are the in-plane air velocity vectors.

The movie is slowed down 10 times and it is looped 5 times.

Lift in hovering hummingbirds

2009-08-27T11:50:00.004+02:00

A new paper published in Proceedings R Soc B (still as FirstCite) explores the lift generating mechanism in hummingbirds. The study is made by the team Warrick, Tobalske and Powers, i.e. the same group that published a paper on hummingbird wakes in Nature in 2005. This is their follow up, now looking closer to the wing with their PIV cameras. The leading edge vorticity is not as prominent in hummingbirds as found previously for hawkmoths and bats (in Lund), but is more varying and with a mean contribution to lift of 16%. I think that everybody expected a big fat LEV in hummingbirds, being classified as honorary insects by some, and so this study shows an unexpected result. It is always a challenge to explain the unexpected, but we are facing some interesting phenomena here and we should soon be able to compare these results with that of avian hovering, such as in pied flycatchers.

The paper can be found here:

http://rspb.royalsocietypublishing.org/content/early/2009/08/05/rspb.2009.1003.full

New lab publication!

2009-08-25T09:14:00.003+02:00

Once upon a time, a group of us sat down at a MIGRATE) meeting and decided to write something about how technology could impact migration research. Now, an undisclosed* amount of time later, the manuscript, titled "Integrating concepts and technologies to advance the study of bird migration," has finally been pre-printed in Frontiers in Ecology and the Environment, which is similar to TREE.

You can find our review here.

Enjoy!

*an embarrassingly long time

Call for abstracts/symposium announcement - Integrative Migration Biology. Deadline 11 September.

2009-08-21T14:29:00.002+02:00

Hi Animal Flight Lab!

I know not all of you work on migration, but I thought I would post this here anyway.

We are sending out a call for abstracts to present in a session complementing our symposium, Integrative Migration Biology, which will be held at the 2010 Society for Integrative and Comparative Biology (SICB) meeting, Jan. 3-7, in Seattle, WA. We would especially like to extend this invitation to students and post-docs, but welcome abstracts from all researchers currently studying animal migration. As a student or post-doc, this would give you a wonderful opportunity to interact with some of the top researchers in the field of animal migration. We welcome submissions for both contributed papers and posters, and encourage students to apply for SICB’s Charlotte Mangum Student Support Program. Please check out the SICB meeting page at for more information.

Billions of animals migrate each year, and they can have enormous effects on the communities and ecosystems they inhabit. We wish to bring together researchers from all over the world who are attempting to integrate ecology, evolution, behavior, physiology, and theory in order to understand the phenomenon of migration. In order to migrate, organisms themselves must integrate many aspects of behavior, physiology, genetics, and morphology. Migration is therefore an excellent system in which to study adaptation and the interplay between various ecological and evolutionary levels of analysis. Traditionally, however, researchers have tended to focus on one narrow aspect of migratory behavior to the exclusion of all else. More recently, biologists have begun to examine multiple aspects of migration in order to better understand this important life history strategy. The primary goal of this symposium is to bring these researchers together with students and post-docs who are just staring their research programs in order to foster discussion and collaboration and further the development of integrative migration biology research.

This symposium and the complementary session(s) are designed to provide a venue for researchers from around the globe to discuss the past, present, and future of migration research. The list of symposium speakers and preliminary titles include:

1. Melissa Bowlin (Lund University), Isabelle-Anne Bisson (Princeton University), & Martin Wikelski (Max Planck Institute for Ornithology). "Integrative migration biology: Past, present, and an exciting future."

2. Marilyn Ramenofsky (University of California Davis). "Endocrine and metabolic parameters coincide with daily fueling and flight cycles of captive migrants."

3. Anders Hedenström (Lund University). "Testing migration theory: the utility of inegrative approaches using field experiments and wind tunnels."

4. Chris Guglielmo (University of Western Ontario). TBA

5. Susanne Åkesson (Lund University). "Endogenous migration programs, migratory fattening and orientation in passerine birds."

6. Kasper Thorup (University of Copenhagen). "Understanding the migratory orientation program in birds: extending laboratory studies to studying free-flying migrants in a natural setting."

7. Tom Kunz (Boston University). TBA

8. Nir Sapir (The Hebrew University of Jerusalem). "The effect of weather on migrating bee-eaters studied by radio-telemetry and numeric atmospheric model."

9. Judy Shamoun-Baranes (Amsterdam University). "Integrating measurements and models to study the influence of weather on migration."

10. Peter Marra (Migratory Bird Center, Smithsonian Institution). "Seasonal interactions and carry-over effects – understanding migration in the context of the annual cycle."

11. David Wilcove (Princeton University). TBA

Additional information will be posted on our symposium website, which we will put up here: once we have finalized some additional details. If you have questions about the symposium or the meeting, please contact us at melissabowlin at gmail dot com or ibisson at princeton dot edu.

Funding for this symposium was provided by MIGRATE, an NSF-funded Research Coordination Network, and SICB.

Note: in order to ensure that your talk or poster will be placed in the correct session, be sure to put our symposium, Integrative Migration Biology, into the field following the statement, "I would like to be in a session complementing a regular symposium" on the abstract submission form on SICB’s meeting webpage.

We hope to see you in Seattle!

Breaking news

2009-07-12T22:35:00.000+02:00

Hi all,

Here is my follow-up to melissa's post:

Yes, Lieke and i got a son today! His name is:

Max Muijres

Isnt he georgeous. The detailed specs about him can be found in image 2.

Greetings,
Florian

Ps. The pics are not the best quality, but that's the first proof of
the fact that your priorities change when you get a kid (as one
advisor of mine clearly explained to me ;)

A little birdie just told me...

2009-07-12T17:38:00.002+02:00

...that we have a new arrival at the flight lab named Max Muijres! Congratulations Florian and Lieke!

(Sorry, I have no pictures...yet!)

...more from SEB

2009-07-05T13:45:00.005+02:00

Since I'm finally back from Glasgow and back online I also wanted to add some information from the SEB conference. So first, I wanted to say that also Per gave an excellent talk but it was a pity that he wasn't in the Biomechanics session! But maybe he did a good thing in getting some genetics people interested in swifts...

On Tuesday I went to the radio workshop with Alun Lewis, who had worked for the BBC a long time and gave us many interesting and useful tips how to perform in a radio interview. Since the rest of the world has a hard time understanding scientists and has no chance of gaining knowledge if we don't try really hard to get out of our science language. I was interviewed on how we can be like superheroes :) It was a great workshop!

Unfortunately I can't tell you anything about the last day, because I wasn't at the conference any more, but instead I made a trip to Loch Ness and the Highlands, which I enjoyed a lot! Here is a small impression of what I saw that day:

Day 3

2009-07-01T10:20:00.002+02:00

Before I get to day 3, I just want to add a bit to what Per posted yesterday. On Monday I bounced back and forth between the biomechanics session (which he's already given a great overview of) and the evolution of evolution session. One great talk was by Bill Sellars, who had created a computer model where you could put in skeletons and add tendons and muscles and then use a genetic algorithm to make things walk. He started out with humans, and after a few generations showed us the 'best' model, which really couldn't walk very well--I couldn't help thinking of the old Monty Python skit about the Ministry of Silly Walks! But then he moved on to hadrosaurs, and showed that given their skeletons and morphology, they were probably more likely to be quadrapedal than bipedal, though it might depend on speed.

...Except that at one point, the genetic algorithm found a bipedal gait that was better than normal bipedalism or quadrapedalism: hopping like a kangaroo! As he said, GAs are great for exploring parameter space, and for generating hypotheses we wouldn't have even considered (though he doesn't think that hadrosaurs actually hopped due to strain on the skeleton).

Yesterday's highlight for me was a talk by Steve Cook on conservation physiology as a discipline using his research on the Fraser River sockeye salmon as a case study. He argued that because physiologists can link cause and effect (when water temperatures are warm, parasites grow faster, and those parasites kill the fish), whereas demographers and more 'traditional' conservationists can only get correlations (when water temperatures are warm, fish die). It got me to thinking--is there any way that we, as biomechanicists/people who study animal movement, can inform management decisions? (Actually, I saw a great talk at SICB a few years ago looking at the performance of hatchery-bred fish vs. wild-caught fish which showed that hatchery-bred fish are quite useless when it comes to escaping predators.) Is there anything like that we could do with birds or bats? I don't know how it is in Sweden, but in the US you're much more likely to get funding if you can bend your research conservation-wards.

Yesterday was also the dinner and dance, which was a lot of fun. Today there's very little biomechanics, but lots of physiological energetics...so that's where I'll probably be!

Second day of SEB Glasgow

2009-06-30T09:59:00.003+02:00

Short report from the second day:

This day I spent almost entierly in the Biomechanics sessions. There were several interesting talks about stability in walking and running on both humans and other animals. Furthermore this day was the one with the "flight-session", in which Rhea and Melissa had their talks. Rhea had a very nice talk about the comparison between the two bats species beeing studied in Lund. It was an exellent talk showing very nicely comparisons between both kinematics and aerodynamics, with some nice movies on SDPIV results and the beautiful iso-surfaces. Melissa held her fascinating talk about the effect of moult gaps on kinematics and aerodynamics of the flycathcers. This talk was also very good and showed very clearly the impact of the moult gap on both kinematics and aerodynamics. Good work both of you! My talk was not in the Biomechanics session, but in the General Biology session. I talked about flight speeds in swifts during three different seasons and behaviours; spring migration, autumn migration and summer roosting.

Furthermore, in the biomechanics session, there were a couple of talks about butterfly and hawkmoth flight, with some application to MAV design. Very impressive work. Anna Carruthers talked about here Steppe Eagle and the function of the leading edge flap and some CFD analysis on high angles of attack during landing. Bret Tobalske had a nice talk about muscle activity and metabolic rate in hummingbird including power curve estimate. Excellent.

After the sessions we all took a walk through the city center all the way to the Cathedral. This was an impressive building, as many others are in this city. We all returned to our hotels satisfied and tired from a full day of impressions.

Per

Greetings from Glasgow!

2009-06-28T21:35:00.005+02:00

As Day 1 of the conference draws to a close, I thought I would post a quick update. I spent most of the day in the Evolution of Evolution: What would you tell Darwin? symposium in honor of Darwin's 200th birthday, though I caught a few biomechanics talks in the afternoon. In between talks and the welcome wine trail event, Per, Rhea and I walked through the city, trying to find a building you can see from my hotel room window that I jokingly dubbed the Fairy Tale Castle. We found it--and found out that it was actually the main university building, which you can see pictured to the right (sorry for the quality--I have a cheap camera). I'm quite jealous of the students at Glasgow University!

This is what the entrance looked like. Sadly, it was behind a locked gate--it's apparently not open on Sundays.

Highlights of the day:

Seeing Rosemary and Peter Grant again and getting an update on the finches through their symposium talks: the effects of La Nina droughts on G. fortis have been completely reversed on Daphne Major due to the establishment of a population of G. magnirostris!
Seeing Bret Tobalske again; he talks tomorrow in the same session Rhea and I are talking in.
A talk on the evolution of whales by Michael Berenbrink about how to physiologically solve the problem of holding your breath for hours at a time. It turns out that whales--and other diving mammals and even birds--increase the solubility of myoglobin in their muscle tissue by evolving myoglobin with a higher net positive charge. In other words, mutations to amino acids that decrease the net charge of the protein appear to be favored in diving animals. This then allows them to keep more myoglobin in their muscle, which can hold onto large amounts of oxygen during long dives. Very neat!

Flight lab at SEB

2009-06-26T23:31:00.003+02:00

During next week the annual scientific meeting of the Society for Experimental Biology is taking place in Glasgow, Scotland. This is a major arena for animal flight related work, and the Lund Animal Flight Lab is represented by three members - all giving oral presentations about their work. Melissa Bowlin is talking about "the aerodynamics of moult gaps", Per Henningsson is presenting work on "flight speeds in swifts" (partly based on his recent Proc R Soc B paper), and Rhea von Busse is talking about "Bat kinematics and aerodynamics". I am sure all these talks will be of great interest to the lucky audience. If possible, we will be able to read daily bulletins from the SEB conference composed by Melissa, Per and Rhea on this blog. Looking forward to getting updated about the research front of our field.

New Journal Impact Factors

2009-06-24T16:50:00.003+02:00

Each year ISA publishes what is called "impact factors" for scientific journals (see Table below). The impact factor (IF) basically measures how often papers are cited that have been published in that journal during the last two years. The impact factor may not be a good guide about the importance of a paper, but I think we do, consciously or unconsciously, select where we publish our papers partly based on a journals IF. Just for fun, I assembled some of the new IFs for our favourite journals, and some others for control. The Journal of Avian Biology still comes out as top of the heap in the category ornithology, but the Auk is very close and has been so for quite some years now. Nature and Science are still around 30, Proc Roy Soc B has 4.25, JEB has 2.98, while J R Soc Interface has 3.62. The engineering journals are always much lower than the biology ones, with Exp Fluids at 1.85. At the medium level we find PloS Biology (12.68) and PNAS (9.38), which perhaps soon should get the honor of publishing some wind tunnel stuff.

Journal	Impact Factor
Phil Trans R Soc	5.556
Proc R Soc B	4.248
J Exp Biol	2.981
J R Soc Interface	3.621
TREE	11.904
Funct Ecol	3.699
Oikos	2.97
BES	2.917
MEPS	2.631
AIAA J	1.025
Exp Fluids	1.854
J Avian Biol	2.327
Auk	2.303
Wilson Bull	0.47
Nature	31.434
Science	28.103
PNAS	9.38
PLoS Biology	12.683

Scaling of moult

2009-06-16T10:29:00.005+02:00

In a New paper published in the open access journal PLoS Biology, Siewert Rowher and co-workers investigate how the duration of moult scales with body size. They find that moult takes progressively longer to complete as the bird gets larger, and argue that moult is a significant player in the evolution of body size in birds. At a size above approximately 3 kg an annual complete moult is no longer possible according to Rowher et al's analysis, and we get phenomena such as sabbaticals form breeding and 'staffelmauser'. A mechanistic explanation for the the observed scaling is also presented. The paper is also commented by Nature.

Diving Anna's hummingbirds

2009-06-15T22:15:00.004+02:00

Courtship dives of Anna's hummingbird offer insights into flight performance limits, by Christopher James Clark, Berkley.

Proc. R. Soc. B

In this new paper the dice speeds of displaying hummingbirds was found to be 27.3 m/s, representing 385 body lengths per second. It is claimed to be the highest size-specific dives measured this far, and it should represent a body drag coefficient of less than 0.3. This resembles me of a paper on diving birds recorded by radar in Spain, as they reached southern Spain after the crossing of Sahara in spring. In that study, Felix and I recorded terminal velocities in barn swallows at about 50 m/s, i.e. nearly double that in the hummingbird. However, due to the more than twice longer body length in the swallows they will not quite reach the 385 body lengths per second as the hummingbird. What is interesting here is that the hummingbird appears to reach 27 m/s with flapping wings, and hence some significant profile drag in addition to the drag of the body. As we are currently concerned with drag of bodies and various random additions, this paper may be quite relevant.

Felix Liechti is visiting

2009-06-03T09:03:00.004+02:00

Felix Liechti, head of the Swiss radar research group is visiting this week, and he is arriving already on Thursday evening, but leaves on Monday morning. This means that we have Friday for work on the light logger experiments, or rather for starting working on it. I hope as many as possible will be here Friday, when we will also be able to talk to Felix about research in his group.

2009-05-27T12:43:00.002+02:00

Next lab meeting will be on Friday at 10:00, Argumentet, where we will discuss our wish list for the CAnMove technological innovation lab. What can they do for us, and what do we want them to do. Yesterday Arne and Johan presented themselves at the CAnMove seminar, and my impression was that potentially they can be very useful to us. I will meet with them next week as part of their "inventory" to present what we decide on.

2009-05-26T12:28:00.001+02:00

Dear All Animal Flight Lab members!

To facilitate communication among us I have created this blog, and invited you all as writers. You only have to get a google account (which I am sure you already have), and then you can post whatever could be of interest. I was thinking of highlighting new research papers, from ourselves or others, information about meetings and anything else of relevance. Hope you find this a useful way of communicating.

Anders