Chiaroscuro geolocator
A Light Level Geolocator or short Helldunkellokator is to the routes from a scientific device that was designed elephant seals and (miniaturization of devices) the routes of bird migration to pursue small birds.
With small birds like the wheatear , which weighs only approx. 25 g , it is not possible to provide them with a satellite transmitter. The device would be too heavy for the bird, whose population flies in Alaska via Northern Russia , Asia , the Caspian Sea to East Africa ( Sudan to Kenya ) and back and thus covers 15,000 km twice a year.
The modern chiaroscuro locator weighs less than 1 g and is attached to the bird's back. It consists of a photocell that measures the light intensity, a clock and a chip to record the light intensity over time. The results can be read out later. The geographical longitude can be calculated from the time between noon (greatest brightness) and midnight , and the geographical latitude can be calculated from the duration of daylight and night length . The train route can be determined from these values.
It was found that the wheatear flies for hours at a speed of around 50 km / h and, depending on the wind, covers 450 km per night on its long-distance route.
literature
- Franz Bairlein , D. Ryan Norris et al .: Cross-hemisphere migration of a 25 g songbird. In: Biology Letters . Received December 15, 2011. Accepted January 24, 2012. Online ISSN 1744-957X .
Web links
- Rembert Unterstell: “We'll be gone then” To research the mechanisms of bird migration using the wheatear model. In: research - The magazine of the German Research Foundation from October 4, 2013, pp. 10–13.
Individual evidence
- ↑ Burney J. Le Boeuf, Richard M. Laws: Elephant Seals: Population Ecology, Behavior, and Physiology - Theory of Geolocation by Light Levels. Berkeley: University of California Press, 1994, accessed January 6, 2014 .