Swifts and swallows on the news

This weekend one of the Swedish National TV shows visited Susanne Åkesson and Anders Hedenström during their fieldwork on swifts and swallows on Öland. See the clip from "Rapport" (starting 16.00).

Sydsvenskan about insect research!

Today Sydsvenskan reports on some of the CAnMove releated insect research going on at the moment. Read more about Mikkel, Maren and Lumbo!

New paper on 3D tracking!

(A) Picture of the stereo vision system, composed by two cameras (Cam1 and Cam2) that overlook the entire aquarium from different angles. (B) Air-cooled blue-light lamp used to excite the red and yellow fluorescent nanoparticles. (C) Schematic top view of the system with cameras positioned 90° from each other.

Computer vision applications are very useful to study animal movements, but due to their intrinsic complexity they are challenging to design, implement, and use properly.  In our new paper (see http://aslo.org/lomethods/free/2013/0278.html) we describe a laboratory system for tracking zooplankton in 3D. We demonstrate the crucial importance of using a correct calibration for proper interpretation of animal swimming behaviour and why 2D tracks are unable to give complete information on Daphnia movement performance.

This new system is currently used to investigate how zooplankton deal under multiple risks – such as UV radiation and predation – and how individual difference in behavioural responses might affect the functioning of aquatic ecosystems. More to come soon…

/Giuseppe et al.

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