# data[].attributes.body
Radio telemetry is a technique that allows scientists to track a study animal remotely.  A study animal is captured, a transmitter is attached to it, and the animal is released.  The transmitter broadcasts pulsed signals over the electromagnetic spectrum that can be picked up by an antenna and receiver used by the researcher [7].

# data[].attributes.attachment_link.entities[].name
Animal Position With Radio Telemetry Data

# data[].attributes.attachment_link.description
A basic introduction to the art of telemetry.

# data[].attributes.headline
How is the Transmitter Attached to the Animal?

# data[].attributes.subject
How is the Transmitter Attached to the Animal?

# data[].attributes.body
There are a variety of different transmitter styles that are chosen to least hinder the study animal.  Radio collars are common for large mammals, some birds can wear a backpack style harness that ensures that the transmitter does not interfere with the wings, and some transmitters are glued directly onto the animal, like the transmitter on this turtle's shell.  The assortment of transmitter styles available makes radio telemetry applicable to a wide variety of potential study animals. [2, 5, 7] Image [a]

# data[].attributes.headline
How do Scientists Locate a Study Animal After Release?

# data[].attributes.subject
How do Scientists Locate a Study Animal After Release?

# data[].attributes.body
Using an antenna connected to a receiver, a scientist can pick up the pulses being broadcast by the transmitter on an animal. Each transmitter will send out a signal at a particular wavelength, so the scientist must tune their receiver to the proper wavelength for the animal they wish to locate.  Antennas can be hand held, vehicle mounted, or even mounted on permanent structures such as towers. [7] Image [b]

# data[].attributes.headline
How Accurately can the Location of an Animal be Determined?

# data[].attributes.subject
How Accurately can the Location of an Animal be Determined?

# data[].attributes.body
It depends.  Using a single antenna will tell you the direction in which the animal is located and its relative distance away based on the strength of the signal, but cannot give you a precise location.  For a study focused on presence/absence, this might be enough.  To pinpoint a study animal's precise location, at least three antennas are needed to triangulate where the signal is coming from. [7] Image

# data[].attributes.body
The California Condor (Gymnogyps californianus) nearly went extinct in the 1980s, when scientists made the decision to capture all remaining wild individuals and institute a captive breeding program. Release of captive-bred birds to reestablish the wild population began in 1997, but many threats are still present in condor habitat, most notably residual lead ammunition from hunting activity. In order to keep track of released condors and monitor habitat usage, reproductive activities, and mortality, every individual that is released is fitted with a transmitter tag.  Radio telemetry data from before all wild condors were taken into captive breeding has been helpful in illustrating the traditional range and movements of the species to ensure that scientists can perform releases in locations that are likely to be most successful for the birds [4, 6, 9] Image [d]

# data[].attributes.headline
Case Study: Jaguars in the Brazilian Panatal

# data[].attributes.subject
Case Study: Jaguars in the Brazilian Panatal

# data[].attributes.body
Researchers in Brazil used radio telemetry to estimate the movement and density of jaguars (Pathera onca) in the Panatal, the world's largest tropical wetland. As is common in large cat studies, radio collars were used as the transmitter device of choice.  By tracking the collared cats, researchers were able to determine that previous estimation methods for jaguar density were likely resulting in overestimations. For a threatened species such as the jaguar, an overestimation of population density can result in an under-representation of threat level to the population and thus a delay in necessary protection measures. [8] Image [e]

# data[].attributes.body
Battery life can be a limiting factor in the usefulness of transmitters attached to study animals.  The size of a battery in a transmitter is directed related to its lifespan, and the battery is the main contributing factor to the weight of the transmitter.  This means that smaller animals, which require a smaller and lighter transmitter, may not be able to be tracked for extended periods of time.  For example, there are now transmitters small enough to be attached to an insect, but their battery life is only 7-21 days. [5, 7] Image [g]

# data[].attributes.body
There is disagreement in the scientific community about how to determine the maximum size/weight of transmitter that should be attached to a particular animal.  A 5% rule is commonly referenced (the transmitter should weigh no more than 5% of the study animal's total body weight) but this does not seem to hold across all animal sizes.  Most scientists do agree that an improperly selected or applied transmitter can affect the free-living energy costs of an animal or even restrict normal movement , so each study animal should be carefully considered on a case by case basis to determine the best style of transmitter to be used. [1, 2, 3, 5] Image [h]

# data[].attributes.body
Newer transmitter and receiver technology can allow for automated tracking of study animals, which allows researchers to collect continuous data without physically going out into the field with their own antenna and receiver. Stationary antenna and receivers can even be connected to the internet or the cell phone network to allow for around the clock remote access to data. [7] Image [f]

# data[].attributes.body
[1] Aldridge, H. D. J. N., & Brigham, R. M. (1988). Load Carrying and Maneuverability in an Insectivorous Bat: a Test of the 5% “Rule” of Radio-Telemetry. Journal of Mammalogy, 69(2), 379–382. http://dx.doi.org/10.2307/1381393

[2] Casper, R. M. (2009). Guidelines for the instrumentation of wild birds and mammals. Animal Behaviour, 78(6), 1477–1483. https://doi.org/10.1016/j.anbehav.2009.09.023

[3] Godfrey, J. D., Bryant, D. M., & Williams, M. J. (2003). Radio-telemetry increases free-living energy costs in the endangered Takahe Porphyrio mantelli. Biological Conservation, 114(1), 35–38. https://doi.org/10.1016/S0006-3207(02)00416-0

[4] Kelly, T. R., Grantham, J., George, D., Welch, A., Brandt, J., Burnett, L. J., … Johnson, C. K. (2014). Spatiotemporal Patterns and Risk Factors for Lead Exposure in Endangered California Condors during 15 Years of Reintroduction. Conservation Biology, 28(6), 1721–1730. https://doi.org/10.1111/cobi.12342

[5] Kissling, W. D., Pattemore, D. E., & Hagen, M. (2014). Challenges and prospects in the telemetry of insects. Biological Reviews, 89(3), 511–530. https://doi.org/10.1111/brv.12065

[6] Meretsky, V. J. (1992). Range Use and Movements of California Condors. The Condor, 94(2), 313–335. https://doi.org/10.2307/1369205

[7] Migratory Conservation Project. (2017). Radio Telemetry. Retrieved from http://www.migratoryconnectivityproject.org/vhf-radios/

[8] Soisalo, M. K., & Cavalcanti, S. M. C. (2006). Estimating the density of a jaguar population in the Brazilian Pantanal using camera-traps and capture–recapture sampling in combination with GPS radio-telemetry. Biological Conservation, 129(4), 487–496. https://doi.org/10.1016/j.biocon.2005.11.023

[9] Ventana Wildlife Society. (2015). California Condor Recovery. Retrieved from https://www.ventanaws.org/california-condors.html

# data[].attributes.body
[a] Reitz, M. (Photographer). (n.d.) Adult female western pond turtle with an attached radio transmitter and identifying number for population monitoring. [Photograph]. Retrieved from https://www.eopugetsound.org/articles/western-pond-turtle-actinemys-marmorata-formerly-clemmys-marmorata
[b] Wildlife Radio Telemetry Equipment [Photograph]. (n.d.) retrieved from https://scientificservices.eu/item/wildlife-radio-telemetry-equipment-/2010
[c] An Illustration of a Good Triangulation [Digital Image]. (n.d.) Retrieved from https://frinsproject.wordpress.com/field-methods/radio-telemetry-and-triangulation/
[d] Huntington, T. (Photographer). (n.d.) Redwood Queen forages over the beach along Highway  1
at Big Sur. [Photograph]. Retrieved from https://www.fws.gov/cno/newsroom/featured/2016/redwood_condors/
[e] Jaguar with Radio Telemetry Collar [Photograph]. (n.d.) Retrieved from https://latimesblogs.latimes.com/unleashed/2009/03/jaguar-macho-b.html
[f] Radio Telemetry Tower [Photograph]. (n.d.) Retrieved from https://www.mynorthbaynow.com/20851/motus-wildlife-tracking-tower-will-put-north-bay-map-wildlife-tracking/
[g] Hamer, G. (Photographer). (n.d.) Triatoma gerstaeckeri kissing bug with radio transmitter. [Photograph] Retrieved from https://entomologytoday.org/2018/07/09/kissing-bugs-kiss-hiding-spots-goodbye-radio-transmitters-telemetry-chagas-disease/
[h] Wood stork with VHF"piggy back"
transmitter on satellite unit [Photograph] (n.d.) Retrieved from http://www.americanwildlifeenterprises.com/critterwithmitters.html