New paper on flight speeds of birds

When we wish to calculate how far a bird can migrate given a certain fuel load, or how fast a bird is expected to fly in a specific context (such as display, foraging or migratory flight), we often make use of flight mechanical theory. The backbone of this theory is the U-shaped relationship between power required to fly and the flight speed through the air (airspeed). The theory was developed/adapted for bird flight more than 40 years ago by the English scientist Colin Pennycuick. Over the years Colin has amended the theory by various experiments and measurements, often involving wind tunnels. Accurate predictions from this theory rely on a number of parameters that describe the aerodynamic properties of the avian body and the wings. Some of these parameters, the induced drag factor and the body drag coefficient, have now been explored in the light of new measurements of flight speeds using an ornithodolite. It turns out that birds are probably more efficient in generating the lift than previously assumed, and also that the body drag coefficient (describing how much drag the body is generating) may vary among species. 

The fieldwork for this study was carried out last autumn by CAnMove scientists together with Colin Pennycuick, who is at Bristol University, using a new ornithodolite consisting of a Vector range finder (a pairs of binoculars with a laser range finder), an anemometer for wind measurements and a computer for data recording. The fieldwork was carried out on the south east coast of Öland during the autumn migration period in 2012, where large numbers of a variety of species migrated. The paper is published in the Journal of Royal Society Interface, and is open access.

/Anders Hedenström 

A foraging cost to migration in fish

Migration is a phenomenally widespread behaviour in the animal kingdom. Yet even for migratory species it is very common that not all individuals migrate within a population (“partial migration”). What maintains these two very different strategies (migrant and resident) in animal populations is still largely a mystery, although recent work into partially migratory freshwater fish (the roach) has shed some light on this fascinating problem.

Roach migrate out of lakes in the winter into streams, returning in the spring. Or at least some of them do, whilst others remain resident the whole year round in the lake. A recent study showed that this migration may function as an antipredator behaviour, with predation from voracious piscivorous birds (cormorants) being significantly lower in the streams compared to the lake during winter (see here). So if the benefits of migration are so great, why don’t they all do it?

One reason might be that migration can be costly. Roach migrate into streams that are most likely food poor environments compared with the lake. In our study, published in PLoS One (see here), we test this idea, and quantify a foraging cost to migration in the roach. By assaying the gut contents of both migratory and resident roach in Lake Søgård in Denmark throughout the migratory season (in collaboration with our buddies at the Danish Technical University), we found that migrants had less food in their guts and also lower quality food items. Hence our data supports the idea that migration involves ecological trade-offs between predation and energy acquisition (the p/g model).

The next puzzle is to ask why certain individuals adopt a migratory or resident strategy. In fitness terms, are these strategies equivalent? Is the behaviour genetically fixed or phenotypically plastic? We will keep you posted…

Tack!

//Ben et al.

Congratulations Rachel!

Zebra finch

CAnMove PI Rachel Muheim received 1.2 million SEK from The Crafoord Foundation for her research on the behavioural, physiological and neuroanatomical mechanisms of magnetic compass orientation and polarized light sensitivity in birds.

We are very happy for her success and wish her good luck with her research project!

CAnMove database progress

Tracking radar on the Ecology House, Lunds University

The first building block of the CAnMove database is ready. It comes in the shape of the table definitions for tracking radar data and routines for population of the database. While there will be a core of tables in common for all kinds of data sets, several of them will in addition have their own set of tables tailored to their specific needs. Two data sets with tracking radar data has also been successfully loaded into the database in a test environment. The next step will be to take a look at satellite telemetry data.

If you have any questions or comments you’re welcome to contact me!

Mats Svensson

Congratulations Maren!

Some weeks ago the Faculty Newsletter highlighted that Maren Wellenreuther was granted a prize from the Konung Carl XVI Gustafs 50-årsfond för vetenskap, teknik och miljö. Congratulations Maren! Read her account of the award ceremony at the Royal palace in Stockolm:
 

When the Swedish King Karl Gustaf turned 50 years he created the ‘Konung Carl XVI Gustafs 50-årsfond för vetenskap, teknik och miljö’. The Foundations purpose is to promote research, technological development and entrepreneurship, which contribute to the sustainable use of natural resources and biodiversity conservation. Every year since then, between 15-20 young scientists receive this award for their scientific accomplishments and are invited to meet the King at his Royal Palace in Stockholm. I was one of the 16 receivers of the award in 2013 and travelled to Stockholm on the 27^th of May to receive my award certificate, money and to shake the hands of the King. We were all greeted by the secretary of the foundation, were seated alphabetically and then got a short lecture about etiquette. We learned to address the King as ‘your majesty’ or ‘your excellence’ and to not turn our backs to the king.

Then the king arrived and we all stood up to greet him. The secretary called our name alphabetical order, and read out a summary of our scientific achievements and how much money was awarded to us. We had to stand up during the 3-4 minutes that it took for the secretary to give all the details. 

 

The 16 receivers of the 2013 award are seated alphabetically in the front row.

Once all awardees were introduced, the king addresses us and said (among other things): "Ni jobbar med viktiga frågor som kan göra skillnad i framtiden. Stipendiet är en uppmuntran att fortsätta ert fantastiska arbete." 

 

Me and Karl, at the Bernadotte Library at the Royal Palace.

As scientists, it is not every day that our science is honoured in a special way, and so it was nice to feel special for once. Then we got to shake the hand of the King and received our certificate and cheque.

Once we had all received our awards, the royal guest professor Nancy Langston from Wisconsin, who spent the last 9 month at Umeå University, gave a guest lecture entitled "Toxic fish - a history". Professor Nancy Langston is a leader in the international emerging field of environmental history. Afterwards, we all got to mingle with a glass of champagne which gave us the opportunity to get to know the other awardees. 

I took the train back home after the ceremony and felt exhausted but happy. I am glad I went to Stockholm and got to experience this.

//Maren