Symposium "Navigation techniques: How do air navigators and animals find their way?"

Pinky on a Catalina in 1944.

On April, 27 2012, it is time for another CAnMove symposium. This time, we will focus on the question, how animals and the old air navigator find their way around the planet. Which features do they use, what sort of techniques have they developed to navigate? And (how) do the navigation strategies, used air navigators and "other animals" differ?

We are very happy to welcome Air Commodore ‘Pinky’ Grocott, Moderator E-Mail Animal-forum, RIN, as one of our symposium speakers. Pinky will give us an appreciation of the techniques he used to apply as an air navigator, mainly relying on the natural features of the universe – some of which may also be used by animals to navigate.

But what do animals, such as sea turtles, that migrate under water do to avoid getting lost in the ocean on their impressive journeys? We are delighted to have Ken Lohmann, University of North Carolina, Chapel Hill, USA as a guest speaker, who will share insight into this mystery.

Swedish Polar Research Secretariat.

What does a small songbird, that uses the Earth’s magnetic field as reference system to find its way do, when it flies across the North Pole? At the poles, birds are facing steep inclination angles that make it very hard to defer directional information from. Susanne Åkesson went up North to find an answer these questions.

We are very much looking forward to welcoming you all on April 27- the programme promises to take care of an entertaining morning session. Please let me know by E-Mail (miriam.liedvogel@biol.lu.se) if you want to attend, so we make sure there are enough sandwiches ready for the mingling part of the session.

How did the Vikings navigate under cloudy skies?

In a recent paper published in Philosophical Transactions of the Royal Society B, CAnMove coordinator in collaboration with a team lead by an optical physicist Dr Gabor Horváth at Eötvös University in Budapest report on recent findings on how Viking navigators possibly could have used so-called sunstones to determine the position of the sun under foggy and cloudy conditions. The team for part of their work measured the skylight polarization under different optical conditions during an expedition (Beringia 2005) to the North Pole in 2005 organized by the Swedish Polar Research Secretariat. Based on these and additional measurements and psychophysical laboratory experiments we suggest that the optical physical conditions required for sun navigation by using sunstones are met under cloudy and foggy conditions, such that the pattern of skylight polarization are transmitted through the clouds and correspond to the pattern seen under clear sky conditions. Overall there is a reduction in degree of polarization of the incoming light under cloudy and foggy skies, but the pattern of skylight polarization is very similar to what is seen in a clear sky. It has been suggested that Vikings have used Icelandic spar (calcite) or possibly crystals of tourmaline, which are birefringent crystals (linearly polarizing crystals), to determine the Sun’s position when it could not be seen in the sky. It is a theory which has been discussed for a long time, however, still such sunstones have not been found in association with Shipwrecks from the Viking ages. Now we show that the optical prerequisites for sunstone navigation are met.

A more popular account of the recent findings is presented at e.g.
Nature News.

In the issue of Phil Trans also other work are presented from CAnMove scientist Rachel Muheim on polarization navigation in birds and by Marie Dacke and Eric Warrent in the Vision group at the Department of Biology at Lund University on the use of polarized light day and night-active insects.

Susanne

RIN11 conference on navigation

Dear CAnMovers!

Please, do not forget to sign up for the RIN11 conference!

The Royal Institute of Navigation will be holding the Seventh International Conference on how animals navigate (RIN11 Orientation & Navigation Birds, Humans & Other Animals) at Whiteknights Campus, Reading University, UK from midday Wednesday 6April until midday Saturday 9 April 2011.

Abstracts should be submitted to conference@rin.org.uk by 15 September 2010. Notification of provisional acceptance will be given by 30 October 2010.

For more information on conference, please, see news section on CAnMove home page.
/Susanne

Migration from various perspectives: watching, listening and simply being amazed

After many exciting talks and ample discussions on migration over the last couple of days, Friday it was time for some outdoor activities. For a course on the Ecology of Migration taking place during peak autumn migration, a visit to Falsterbo Bird Observatory is a must. Falsterbo is situated on the southwestern tip of Sweden, where migrants concentrate in large numbers during autumn migration. On Friday we eyewitnessed large flocks of Chaffinches, Siskins and Linnets leaving Sweden via Falsterbo on their migratory journey. We also saw numerous migrating raptors, mainly Sparrowhawks, Bussards and some Red Kites, and Karen Persson and Nils Kjellén told us about the ringing scheme and ongoing research carried out at the bird observatory

The afternoon lecture about migration and dispersal of small aquatic organism was given by Karin Rengefors, and the day ended with a poster-session, introducing research carried out in the department of Ecology.

Saturday was filled with a themed lecture block on Orientation and Navigation. Thomas Alerstam set the scene by introducing different compass mechanisms used by animals to orient, and set the pioneer discoveries in this field into today's perspective. Susanne Åkesson provided insight into different navigation principles with a focus on sea turtle and insect navigation, and Tim Guildford took us on a "Nils Holgersson" trip (on a slightly different species, though) and demonstrated pigeon navigation literally from the bird's eye view – amazing what current technology and clever experimental design allows us to investigate! Rachel Muheim told us how animals from diverse groups use information from the Earth's magnetic field for a variety of different behaviours, and summarised the state-of-the-art of ongoing research trying to understand how animals are able perceive the Earth's magnetic field in the first place. In the final session Marie Dacke explained how small creatures such as spiders and insects with brains weighing less than a milligram navigate effectively, and how the South African dung beetle manages to use an optical polarisation compass at night time.

Ascension Island - SATO report III

Georgetown, Ascension Island 2009-05-07

Last night we got an early night. The smallest of the five female green turtles (109 cm carapace length) got her transmitter attached while laying her eggs at Long Beach already at 22.00h. The beach was busy already by then and I could see the sand in the air by several digging females. They did not seem to be so worried about our presence, so I guess they were eager to get done with I all and thereafter leave the Island, as two of our turtles with GPS tags now have done. Some scattered hatchlings were aiming for the sea and the sea was much calmer than two nights ago.

Yesterday afternoon we had a walk to one of the ridges reaching east of the Island, and from there we had an excellent view of the Boatsman’s Island where all the frigate birds and other seas birds, like tropic birds, masked and brown boobies are breeding. On the top I could see the high numbers of frigate birds on their nests, while on the sides the boobies and tropic birds were having their nests. Fairy terns were flying by us at our viewpoint, aiming for the trees uphill Green Mountain where they nest at tree branches and on steep slopes.

Last news – flight delayed due to difficulties to land on The Falklands. They have snow down there. Hard to imagine when the temperature reaches +30 degrees C.

/Susanne