Geolocator
Encyclopedia
A geolocator, light-level logger or bird logger is essentially a lightweight, electronic archival
tracking
device, usually used in bird migration
research to map migration routes, identify important staging areas, and sometimes provide additional ecological information.
{BAS) .which developed the device for recording the behaviour of the Wandering Albatross
. From albatrosses and other seabird
s the use of geolocators has been extended to other migratory species, including tern
s, wader
s, and even small songbird
s.
it is able to record data for long periods of time.
Recording light levels over time produces data on day-length which can be analysed to give continuous latitude and longitude readings of a bird’s long-distance movements. The location data so derived is not as accurate as that from GPS
tracking, but the devices are considerably lighter and cheaper. Other sensors, such as for recording temperatures, or whether the substrate is wet or dry, may be used in conjunction with the light-level loggers in order to provide further ecological information about the bird’s location. The devices may be attached to the bird being tracked by a harness, or simply attached to the band on the bird’s leg. The weights of the geolocators range from about 1 g to 2.5 g, with a battery life of 1-5 years.
Archive
An archive is a collection of historical records, or the physical place they are located. Archives contain primary source documents that have accumulated over the course of an individual or organization's lifetime, and are kept to show the function of an organization...
tracking
Tracking animal migration
For years scientists have been tracking animals and the ways they migrate. One of the many goals of animal migration research has been, of course, to determine where the animals are going; however, researchers also want to know why they are going "there"...
device, usually used in bird migration
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
research to map migration routes, identify important staging areas, and sometimes provide additional ecological information.
History
The use of geolocators for tracking birds was pioneered by the British Antarctic SurveyBritish Antarctic Survey
The British Antarctic Survey is the United Kingdom's national Antarctic operation and has an active role in Antarctic affairs. BAS is part of the Natural Environment Research Council and has over 400 staff. It operates five research stations, two ships and five aircraft in and around Antarctica....
{BAS) .which developed the device for recording the behaviour of the Wandering Albatross
Wandering Albatross
The Wandering Albatross, Snowy Albatross or White-winged Albatross, Diomedea exulans, is a large seabird from the family Diomedeidae, which has a circumpolar range in the Southern Ocean. It was the first species of albatross to be described, and was long considered the same species as the Tristan...
. From albatrosses and other seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s the use of geolocators has been extended to other migratory species, including tern
Tern
Terns are seabirds in the family Sternidae, previously considered a subfamily of the gull family Laridae . They form a lineage with the gulls and skimmers which in turn is related to skuas and auks...
s, wader
Wader
Waders, called shorebirds in North America , are members of the order Charadriiformes, excluding the more marine web-footed seabird groups. The latter are the skuas , gulls , terns , skimmers , and auks...
s, and even small songbird
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
s.
Methods
Geolocators record changes in light levels at different latitudes and longitudes. They do not use satellite or radio technology and, as it is an archival logger, recapturing the bird is necessary to retrieve the device to download the data to a computer for analysis. Because it uses low power technology and data compressionData compression
In computer science and information theory, data compression, source coding or bit-rate reduction is the process of encoding information using fewer bits than the original representation would use....
it is able to record data for long periods of time.
Recording light levels over time produces data on day-length which can be analysed to give continuous latitude and longitude readings of a bird’s long-distance movements. The location data so derived is not as accurate as that from GPS
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...
tracking, but the devices are considerably lighter and cheaper. Other sensors, such as for recording temperatures, or whether the substrate is wet or dry, may be used in conjunction with the light-level loggers in order to provide further ecological information about the bird’s location. The devices may be attached to the bird being tracked by a harness, or simply attached to the band on the bird’s leg. The weights of the geolocators range from about 1 g to 2.5 g, with a battery life of 1-5 years.