Using TrackLab for wildlife tracking

TrackLab is the new solution for tracking and analysing the tracks from free-moving animals in the wild.  It is a complete end-to-end solution consisting of high-quality tracking hardware for data acquisition and reliable state-of-the-art software for visualization and analysis of the tracks. Noldus can provide a complete solution including hardware, software, installation and on-site training.

Tracking technology

TrackLab software is an open platform that can analyze tracks acquired with a variety of tracking systems, including all hardware which can create GPX files. It also supports CSV import of track data, for instance from movebank.org as well as live import. Recent advances in tracking technology mean that GPS trackers are now much lighter and with much better battery life than would have been imagined possible only a few years ago. Neverthess, the right choice of hardware is still critical, as is configuring it properly in terms or sample rate, scheduling, etc. For more accurate tracks, it can also be important to select hardware which supports GPS (or other GNSS) augmentation such as WAAS or EGNOS. Noldus will be happy to provide you with either a completed integrated TrackLab setup, or (if you already have GPS units), just the TrackLab software.

Data Preparation

As with all measurement systems, location measured using GPS devices has errors associated with it. The size of the error varies according to atmospheric conditions, the location of the subjects (for example, deep valleys can block satellite reception), and movement of the subject. The quality of the GPS hardware, and whether or not augmention services are used, also affect the track's accuracy. TrackLab incorporates data processing algorithms to remove outliers and smooth the data, which are specially designed to improve the quality of GPS track data. The quality of the GPS hardware and whether or not augmention services are used also affect the track's accuracy. Furthermore, there is also a powerful function to select and edit individual tracks to improve your data quality.

Track visualization

You can explore and view your TrackLab data in a wide variety of ways:

  • Locations show data for each track point (or GPS fix) including position, speed and acceleration. You can also copy this data to other programs for further analysis and sort and edit the data in this view to remove outliers.
  • Maps show your tracks either in OpenStreetMap or on an image file of a map, which you can create and import yourself. You can pan and zoom the map, and draw points and regions of interest. You can plot the tracks as trajectories (in a variety of styles), or show the sample density as a customizable heat map. The tracks can be played back in a variety of ways, so that both short tracks and those acquired over a long time period can be played back conveniently. There is no limit to the number of points you can visualize.
  • Graphs show the value of a measured variable (such as speed) over time, synchronized with the other views. The data of all the views are synchronized so that you can explore the interaction between, for instance, velocity and location.

The brightness of the colour is an indication of the sample density, that is, it is a integrated function of both the frequency and duration of visits to each point.  In this case, the nest site is clearly visible. The heatmap could be use to determine the location of zones which could be drawn to give a more statistical analysis of the time spent in or near the nest [1].

 

The velocity of the birds can be displayed both as a graph and on the map (synchronized), and the values on the graph can be used to derive appropriate values for classification of the data.

 

There are clear hotspots in Germany (Emsland and Lower-Elbe/Schleswig-Holstein) and in Estonia, and a smaller one in the Dvina Bay of the White Sea, indicating the foraging spots used by the migrating birds [3].

Behavior detection

New technology in tracking systems has meant that GPS tracks are increasingly accurate.  That has opened up new possibilities in terms of increased information which can be obtained from the data. If your behaviors can be separated on the basis of a relatively straightforward parameter such as velocity (e.g. standing/foraging/running/flying), you can classify them of-the-shelf in TrackLab. If you need a more complex classification (e.g. combining accelerometer and GPS data [5]), Noldus will be happy to work with you to implement that for the species you are working with. TrackLab has functions to enable you to import external data such as 3D acceleromter data or manually scored behaviors.

Statistical analysis

You can use the location of your tracked subjects in relation to zones which you define yourself (for example, home range, feeding territories, etc) and also whether or not they are moving, to generate events. Then you can create an analysis report showing detailed information about each of these events. You can also make an analysis report showing a wide range of variables for each of your tracks, with statistics such as duration, average speed, maximum acceleration, movement statistics (according to thresholds you can set yourself), a variety of parameters describing the path shape (for instance, to quantify searching and foraging), and statistics quantifying the zone visits.  Over 50 analysis parameters are available for each track and interval, giving a thorough quantification of the movment, location and searchign patterns of your animals. Statistics are available for the entire track, and for intervals defined by your zones and speed thresholds as well as imported data, for instance manually-scored behaviors. You can even combine different criteria to create complex intervals.

Specifications

TrackLab - Technical specifications and features

Complete solution

Noldus has over 25 years of experience in providing solutions for measuring animal behavior. Recent developments in GPS tracking mean that it is now possible to get much more information about the behavior of animals from their GPS tracks than in the past.  We have created a complete solution including hardware, software and training to enable you to track wild animals and get meaningful data from those tracks. To find out more, please contact us.

References

[1] Data from: Shamoun-Baranes et al. (2012). From sensor data to animal behaviour: an oystercatcher example. PLoS One,7(5), e37997.

[2] Data kindly provided by Andrea Kölzsch & Bart Nolet, Netherlands Institute of Ecology (NIOO-KNAW). Note that the classification is for illustrative purposes only and is not validated.

[3] Data from Nolet, B.A., Kölzsch, A., Oosterbeek, K. and de Vries, P.P. 2013. Stopover sites of satellite tagged Bewick's Swans. Limosa (in press).

[4] Data kindly provided by Fred De Boer, Wageningen University.

[5] Noldus et al. 2013. Detecting animal behaviour from GPS data: towards integrated hardware-software solutions: Presentation at the 9th International Conference on Behavior, Physiology and Genetics of Wildlife, Berlin, 20 September 2013.