Understanding Wolf Behavior from GPS Tracking Data

In this science project, you will download real tracking data from grey wolves in Alberta, USA, using the Movebank.org database. Then you will look at individual wolf tracks and territories in Google Earth Pro and analyze the total size of a gray wolf pack's territory and whether the pack's movements change depending on the season.

Setting Up and Downloading the Wolf Tracking Data

1. To do this science project, you will need to install Google Earth Pro on the computer you are using. Google Earth is a program that allows you to map locations and look at satellite images of places all around the world. Be sure you have permission to download this from the computer's owner before you begin.
2. A free version of Google Earth Pro can be downloaded from Google Support.
   1. You might find it useful to try one of the tutorials or to consult the Google Earth User's Guide to familiarize yourself with Google Earth Pro. The Google Earth general help page is a useful starting point if you have questions about how to use different parts of the program.
3. The next step is to download the wolf tracking data. Go to the Tracking Data Map page in Movebank to access the wolf tracking data. Enter the study name "ABoVE: Boutin Alberta Grey Wolf" into the search box and select the respective study. You can find more details on how this site works in the Movebank "Tracking Data Map" User Manual.
   1. If you want to find out more information about your chosen data set, you can browse the Studies page details for your selected study. You get to the Studies page by clicking on "Studies" in the upper left corner of the page.
   2. Follow the instructions in the Movebank tutorial "Accessing data in Movebank" to download your data. Specifically follow the instructions in the section "Downloading data in Movebank format." Keep all the default settings in the download window and choose "GoogleEarth (Tracks)" as the file type.
   3. Open the downloaded Google Earth file in Google Earth Pro. It will contain the path of each tracked animal on a map, complete with satellite images of each location. Examples of two wolf tracks are shown in Figure 2.
   4. You might find it useful to try one of the tutorials or consult the Google Earth Pro User's Guide to familiarize yourself with Google Earth Pro. The Google Earth general help page is a useful starting point if you have questions about how to use different parts of the program.

Identifying the Wolves' Seasonal Movement Patterns and Territory Size

1. Once the Google Earth file has opened, you will see location points (dots) connected by movement tracks (lines). If you only see lines and no dots, double-click on the study name in your "Places" section in Google Earth Pro. Each animal in the study will have a single color. All the dots corresponding to the location of a specific animal will be in the same color. In Figure 2, tracks of two different wolves are shown. One wolf's data is color-coded light green and the other is color-coded red.
   1. Note: The location points mark coordinates reported by the wolf's tag. The tracks are generated by making the shortest possible line between the two location points that are closest together in time. The tracks are the "best guess" of the path the wolves took, but only the location points are precise data.

Figure 2. Partial view, in Google Earth Pro, of the movement tracks of two wolves. The dots show locations where they were tracked using GPS sensor tags. The lines connect temporally sequential locations in an approximation of the wolves path. (Data shown here was collected by Stan Boutin et al. and accessed through Movebank.)

2. The full wolf data set contains data from 46 animals. Not all the tracks in a study might be good for analysis. Some tracks might have ended prematurely if the tag fell off the animal, if the animal died, or if the tag stopped functioning for technical reasons. Choose a good track for your analysis.
   1. Look at each track individually. To do this in Google Earth Pro, go to the menu on the left-hand side of your screen. Under "Places" you will see the study data. It will show your study name as "ABoVE_Boutin Alberta Grey Wolf.kmz". To see the different wolves in the study, click the little arrow next to the study's name. Now you will see a separate ID number for each wolf. Click the box next to a wolf's ID to select (box is checked) or un-select (box is un-checked) each animal. See Figure 3 for details. Wolf tracks with selected (checked) IDs will be displayed on the map.
   2. Underneath each wolf's ID in Google Earth are the number of location events (n) recorded for that wolf and the time span over which the data was collected. For example, in Figure 3, 2775 locations were recorded from wolf's 32269-33678-32269 GPS tag from March 20, 2012 through July 14, 2012. The best tracks for analysis will:
      • Span a year, or more, of time, thus giving you a view of where the wolf is throughout the entire year.
      • Have a normal or high number of recorded location events compared to other wolves in the study.
   3. Write down in your lab notebook at least ten tracks you consider to be complete and good for analysis.

A cropped screenshot of selected data files in the sidebar of Google Earth. In Google Earth there is a sidebar labeled 'Places' which contains a file tree where files can be toggled on and off using a checkbox. The folder named 32269-33678-32269 and 32262-33668-33668 are selected to be shown on the map.

Figure 3. In this case, wolves with the ID number 32269-33678-32269 and 32262-33668-33668 are selected (checked) and their tracks would be displayed on the map. Wolf 33669-33669 would not be displayed because its ID has not been selected.

3. Once you have a list of ten good tracks for analysis, take a careful look at three of them, using Google Earth Pro. For each wolf track, review the provided data points to find out if their territory changes dependent on the season of the year.
   1. If you click on a location point, it will tell you more information about that point, including the timestamp. The timestamp is when the tag recorded the wolf at that location. Using the timestamps, determine:
      • What the wolf's preferred territory for each season (spring, summer, fall, winter) is. Hint: For each data point, decide which season it falls in. Note, if there are too many data points, you don't have to look at every single one. Selecting two or three out of a cluster of points is probably enough.
      • Approximately how long the wolf spent at each location and how often it traveled in between.
   2. Once you've reviewed the data points on the map and you have found preferred territories for each season, you can use the "polygon" tool in Google Earth Pro to draw the boundaries for each territory. Use a different colored polygon to mark the territory for each season. Some areas may have been visited by the wolves in more than one season. If a particular area on the map is part of the wolves' territory for more than one season, include that section in all of the polygons that represent the seasons when the wolves were located there.
      • Give each polygon a specific name. Every new polygon will show up in your list under places, most likely under the wolf ID that you used to draw your polygon, as shown in Figure 4.
      • To learn how to use the polygon tool, consult Google Earth Pro's help page on Drawing Paths and Polygons.
        
        
        

        A cropped screenshot of selected data files in the sidebar of Google Earth. In Google Earth there is a sidebar labeled 'Places' which contains a file tree where files can be toggled on and off using a checkbox. The selected files include a polygon that has been added to the list after drawing it within Google Earth.

        
        Figure 4. Once you have drawn and saved a polygon, it will show up in the list under "Places" in the left side bar.
        
        
4. In the next step, look at the size of the wolves' territory and make a bar graph to represent the data.
   1. There should be a total of five bars in your bar graph, one each for fall, winter, spring, summer, and one representing the total territory independent of season.
   2. To find out the territory size, select a territory polygon in your Google Earth side bar under "Places". Right click on the polygon name and click on "Get Info." In the window that pops up, there is a "Measurements" tab. Once you click on the "Measurements" tab, you will find the calculated Perimeter and Area for your selected polygon.
   3. Write the area for each of the polygons down in your lab notebook. Do this for each seasonal territory and the total territory for each wolf. To get the total territory, draw a new polygon that surrounds all the data points of one wolf, as shown in Figure 5. Then look at the calculated area for this polygon.
   4. Use the data collected to create a bar graph that shows the seasonal and total territory size for each wolf.
   5. If you need help making graphs, or would like to use an online program to make them on the computer and print them, try Create a Graph.
      
      
      
      Figure 5. Draw a polygon around all the data points of one wolf to determine its total territory.
      
      
5. Calculate the fraction (or percentage) of the total territory that the wolves use in each given season.
6. Use the wolf track data, the Google Earth map, calculations, and graphs to try to answer these questions. Note: there aren't any "right" or "wrong" answers to these questions. You're simply looking at the data and trying to describe any trends that might be there, and come up with hypotheses to explain those trends. That is exactly what scientists do.
   1. During which season do the wolves travel the most?
   2. During which season do they travel the least?
   3. Can you relate their level of activity to the annual cycle of when breeding, pup birthing, and raising young pups occur?
   4. Are there any important natural landmarks (water, areas that might have good food, etc.) that you can spot on the map which may explain why they stay in certain areas?
   5. You may want to test your hypothesis using data from other wolves. The second Variation, listed in the Make It Your Own section, offers a suggestion for two more wolves (in another pack) whose data you could use for hypothesis testing.