A miniature light level logger ( geolocator ) for tracking animal movements for long periods has been designed and developed by engineers at the British Antarctic Survey, but is now under license to Biotrack.
Geolocators can be used for tracking over long distances in any application where the logger usually has an unobscured view of natural light level at dawn and dusk. The loggers must be retrieved for data download.
Our light level geolocator is a miniature, light weight Geolocation/TDR tag recording essential light level information which can be processed to give location latitude and longitude. The devices are small, have low weight and drag, long lasting and cost effective. Although not as accurate as GPS or ARGOS, this method allows a much cheaper and much smaller device to be constructed which records for a far longer time (many years). For seabirds, logging of wet/dry information and sea surface temperature can also be included. The wet/dry recording has been developed to measure the activity of the birds, and the temperature information, when correlated with satellite data, can be used to improve the location fix.
The loggers work worldwide wherever there is dawn and dusk, and have been used so far on a number of species including geese, albatross, penguins, shearwaters, gannets, skuas, fulmars, ducks, shags and seals. Being so small, these geolocators can be attached to leg rings of larger seabirds, thus avoiding problems associated with platform gluing and harnesses. Geolocator accuracy is in the region of +/-150km and uncertainty is caused mainly by shading (including cloud and foliage), interference (non direct sun and artificial light), and for latitude, proximity to equinox and the equator.
MK5... family (0.75g – 1.2g)
Expected life 1 - 3 years (model dependent)
MK6... family (0.39-1.0 g)
Expected life 10 - 24 months (model dependent)
MK3... family (2.5 g) MK4... family (1.5-2.0 g)
Expected life 2 - 5 years (model dependent)
MK5... family & MK7... family (0.75g – 2.0g)
Expected life 12 - 24 months (model dependent)
|Options for Marine Geolocators
||Options for Terrestrial Geolocators
Geolocator stalks are measured from the point at which they emerge from the tag, to the centre of the light sensor.
The stalk extends approximately 4 mm beyond the light sensor for encapsulation. This should be taken into account when considering the effects of drag.
The tolerance on stalk length is ± 1.5mm.
Integrating Information from Geolocators, Weather Radar, and Citizen Science to Uncover a Key Stopover Area of an Aerial Insectivore
Andrew J. Laughlin, Caz M. Taylor, David W. Bradley, Dayna Leclair, Robert C. Clark, Russell D. Dawson, Peter O. Dunn, Andrew Horn, Marty Leonard, Daniel R. Sheldon, Dave Shutler, Linda A. Whittingham, David W. Winkler and D. Ryan Norris
The Auk 130(2):230-239. 2013 doi: http://dx.doi.org/10.1525/auk.2013.12229
Effects of geolocators on reproductive performance and annual return rates of a migratory songbird
Jesús Gómez, Chantel I. Michelson, David W. Bradley, D. Ryan Norris, Lisha L. Berzins, Russell D. Dawson and Robert G. Clark
Journal of Onithology 155: 37- 44 (2014) doi: 10.1007/s10336-013-0984-x
Trans-Gulf of Mexico loop migration of tree swallows revealed by solar geolocation
David W. Bradley, Robert G. Clark, Peter O. Dunn, Andrew J. Laughlin, Caz M. Taylor, Carol M. Vleck, Linda A. Whittingham, David W. Winkler and D. Ryan Norris
Current Zoology 609(5):653-659 (2014) doi: 10.1093/czoolo/60.5.653
Connectivity of wood thrush breeding, wintering, and migration sites based on range-wide tracking
Calandra Q. Stanley, Emily A. McKinnon, Kevin C. Fraser, Maggie P. Macpherson, Garth Casbourn, Lyle Friesen, Peter P. Marra, Colin Studds, T. Brandt Ryder, Nora E. Diggs and Bridget J. M. Stutchbury
Conservation Biology, 29: 164–174. (2015) doi:10.1111/cobi.12352
Geolocators on Golden-winged Warblers do not affect migratory ecology
Sean M. Peterson, Henry M. Streby, Gunnar R. Kramer, Justin A. Lehman, David A. Buehler, and
David E. Andersen
The Condor 117(2):256-261. 2015 doi: http://dx.doi.org/10.1650/CONDOR-14-200.1
Geolocator reveals migratory and winter movements of a Prothonotary Warbler
Jared D. Wolfe and Erik I. Johnson
J. Field Ornithol., 86: 238–243. (2015) doi:10.1111/jofo.12107