Abstract

Objective

Introduction

Have you ever noticed that some of the bird species in your backyard disappear every winter and then reappear in the spring? Where do they go and why? This is a question that has intrigued people for centuries. In fact, discussions about the fate of migratory birds can be traced all the way back to Aristotle in ancient Greece! Aristotle proposed that the redstarts, birds that could be seen all summer, physically transformed themselves into robins during the winter. This idea, as crazy as it seems now, was taken as fact at the time. After all, the two species were not seen in the same area at the same time. But today, thanks to the work of bird watchers and scientists, we know that birds that appear and disappear from a specific geographical location are not transformed into other birds, but instead, are migrating.

The migration, or regular seasonal journey between two or more areas, takes birds from their breeding grounds to their wintering grounds, and then back again every year. For a migratory bird, life in the breeding ground centers on raising and protecting their young. The birds arrive there to find a mate, build a nest, lay eggs, and then feed and protect the offspring from predators. Then, as the seasons change, these migratory birds fly hundreds, or even thousands, of miles to their wintering grounds where they forage for food and store energy for the flight back to the breeding grounds. Some species also travel to additional locations. For example, many swans and ducks, like the common mallard, also journey to molting grounds. The molting grounds are safe locations with few predators and an abundant supply of food, where the birds stay while they lose their old flight feathers and grow new ones. Table 1, below, shows examples of several different migratory bird species and the journeys they undertake.

Table 1. Above are some examples of amazing migrations made every year by different bird species.

	The Arctic Tern (Sterna paradisaea) makes the longest annual bird migration, traveling approximately 19,000 km (12,000 miles) each way between its Arctic breeding grounds and its Antarctic wintering grounds. (Photo by Estormiz, 2006.)
	Even tiny birds, like hummingbirds, can fly many miles. The migration of the Ruby-throated Hummingbirds (Archilochus colubris) often includes a 500-mile nonstop flight across the Gulf of Mexico. (Photo courtesy of U.S. Fish & Wildlife Services.)
	The Common Loon (Gavia immer) typically breeds on freshwater lakes, and winters in the ocean near the shoreline. (Photo by Cephas, 2009.)
	The Swainson's Hawk (Buteo swainsoni) migrates across the equator twice a year to breed in North America and winters in South America. (Photo by Peter Wallack, 2007.)

Why do migratory birds undertake these journeys, and how do they find their way from one location to the next? These are questions that scientists are actively working to answer. To do so, they need to collect many different types of information. The most important facts to figure out are where the birds are, and when they are there. This type of information is called spatio-temporal data, where spatio refers to the space or location of the bird and the temporal information is the time (month, day, hour) that the bird was determined to be at that specific location. To collect this data, scientists put tags on birds. The three most commonly used tags to track migratory birds are: banding, global positioning system (GPS) tags, and Argos Doppler tags. More information about the advantages and disadvantages of the different tags can be found in the Science Buddies guide to Using Animal Tracking Data from Movebank for Science Projects.

When designing a study, the scientists decide which tagging method will best enable them to answer the specific question they're studying. All of the tags require a bird to be captured and the tag to be attached by a person for the first time. The video below shows how scientists physically tag birds.

Watch this video to see how scientists carefully attach a tracking device to a bird's back being careful to not injure the bird. Researchers are always careful to make sure the tag does not inhibit the animal's natural movements. (Video courtesy of Carolina B. Proano.)

Once scientists know the geo-spatial data, they can find out other information, like the weather, type of habitat, and food resources in the locations that are important to the birds. Collectively, this data can be used to investigate questions about why and how specific birds migrate.

In this science project, you'll investigate how temperature influences a bird's migratory behavior. Do migratory birds have a preference for a specific temperature range? Do birds leave their breeding grounds to avoid cold temperatures? Do the breeding and wintering grounds have similar temperature ranges or is migration completely independent of temperature? To explore these questions, you'll use real bird tracking data from Movebank. Movebank is an archive of animal movement data collected by scientists in the course of their studies. Many of these scientists have agreed to share their real data with Science Buddies for you to analyze. You'll be using the same data that scientists are using in their own experiments!

Terms, Concepts, and Questions to Start Background Research

• Migration
• Breeding grounds
• Wintering grounds
• Predators
• Species
• Spatio-temporal data
• Physiological

Questions

• What birds in your area migrate?
• What kind of physiological changes occur between winter and spring for birds that don't migrate?
• How do scientists attach tracking tags to animals?
• What types of data do tracking tags give scientists?

Bibliography

Additional information about how bird migrations are tracked can be found at:

• Fiedler, Wolfgang. (2009). New technologies for monitoring bird migration. Ringing & Migration. Volume 24, pages 175–179. Retrieved December 6, 2010, from http://blx1.bto.org/pdf/ringmigration/24_3/fiedler.pdf

A Movebank tutorial is available at:

• Science Buddies. (2010). Using Animal Tracking Data from Movebank for Science Projects. Retrieved December 6, 2010, from http://www.sciencebuddies.org/science-fair-projects/project_ideas/movebank_tutorial.shtml

Help information for Google Earth can be found here:

• Google. (2010). Google Earth User Guide. Retrieved December 6, 2010, from http://earth.google.com/support/bin/static.py?page=guide_toc.cs

This website details earlier civilizations' explanations of bird migration:

• Armstrong, R. (n.d.). Ancient Explanations of Bird Migration. Retrieved December 6, 2010, from http://www.uh.edu/engines/epi2228.htm

These websites will provide you with more information about animal migrations:

• ParkWise. (n.d.). Migration Basics. Retrieved December 10, 2010, from http://www.nps.gov/akso/parkwise/Students/ReferenceLibrary/general/MigrationBasics.htm
• BBC. (n.d.). World On the Move: Great Animal Migrations. Retrieved December 10, 2010, from http://www.bbc.co.uk/radio4/worldonthemove/species/

Materials and Equipment

• Computer with the following requirements:
  1. Internet access
  2. A spreadsheet program such as Microsoft Excel
  3. Where you are allowed to download a free version of the Google Earth software
• Lab notebook

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Experimental Procedure

In this science project, you'll download real bird migration and temperature data from Movebank.org. You'll look at the migration route in Google Earth and evaluate whether or not temperature plays a role in the species' migration.

Setting Up and Downloading the Migration Data

1. To do this science project, you'll need to install Google Earth 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 can be downloaded from
   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. The Google Earth general help page, earth.google.com/support/ is a useful starting point if you have questions about how to use different parts of the program.
3. Next, you'll need to decide what species you're interested in studying for this science project. Table 2, below, shows a list of species that have available data sets suitable for this science project. Many additional species data sets on Movebank will also work for this project, but the ones listed in Table 2 are the only ones that have been tested.

4. Once you've decided on a species, go to www.movebank.org to access the data. You'll need the study name, listed in Table 2, to find the data. Or you can explore the other data sets available to you at Movebank and choose a bird specie that most interests you.
   1. Follow the instructions in the Science Buddies guide to Using Movebank for Science Projects. Open the Google Earth file containing the migration path of the species in which you're interested.

Analyzing the Migration Path and Temperature Data

1. Once the Google Earth file has opened, you'll see location points (dots) connected by migration tracks (lines). Each animal in the study will have a single color. All the dots corresponding to the location of a specific animal will be the same color. In Figure 1, below, the migration paths of two birds are shown. One bird's data is color-coded orange and the other is color-coded blue.
   1. Note: The location points mark coordinates reported by the bird'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 birds took, but only the location points are precise data.

Figure 1. Partial view, in Google Earth, of the migratory track of two ospreys. The dots show locations where they were tracked using Argos Doppler tags. The lines connect temporally sequential locations in an approximation of the bird's flight path. (Data shown here was collected by Nye, P. and accessed through Movebank.)

2. Using Google Earth, look at all the tracks at once. You should see two geographic areas, connected by the tracks, that have a higher number of location points. These are the wintering and breeding grounds and represent the final destinations for the migrating birds.
3. Which one is the breeding ground and which is the wintering ground? Clicking on a location dot opens a box of information about that data point. The top item in the box is a timestamp. The timestamp tells you when the bird's tag was recorded as being at that particular location. The information is given as year-month-date and time, in a 24-hour format. Determine which location is the breeding (summer) ground and which is the wintering ground, based on the months and when it is the "winter" season at each location.
4. Do all of the birds in this study have the same wintering and breeding grounds? Depending on the species they might or might not.
5. Once you've identified the wintering and breeding grounds, you're ready to analyze the temperature data for individual birds. You'll need to choose at least three representative bird tracks to analyze. 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 tracks that:
   1. Visually appear complete when compared to the other tracks in the study.
   2. Have location points whose timestamps span the duration of the study. Or, for a multiyear study, span at least one year, since these are annual migrations.
      • Note:To look at an individual bird's data in Google Earth, go to the menu on the left-hand side of your screen. Under "Places" you'll see the study data. It'll have a name like "study_[some number].kmz". To see the different birds in the study, click the box with a plus (+) next to the study's name. Now you'll see a separate ID for each bird. Click the box next to the bird's ID to select (box is checked) or un-select (box is un-checked) each bird. See Figure 2, below, for details. Bird tracks with selected (checked) IDs will be displayed on the map.

Figure 2. In this case, birds 3H and 3K are selected (checked) and their tracks are displayed on the map. Bird 3D is not displayed because its ID has not been selected.

6. Take the first good bird migration track you've chosen for analysis and download the temperature data for that individual bird. The Science Buddies guide to Using Movebank for Science Projects has detailed instructions on how to download the temperature data for a bird. Look under the "How do I download a data set?" section for the instructions.
   1. In this case, you are interested in the Surface Temperature data only.
7. Using the Weather tab in Movebank, also download the temperature data for the wintering grounds and breeding grounds for this individual bird.
   1. Detailed instructions about using the Weather tab are available in the Using Movebank for Science Projects guide. In Movebank, download temperature data for the bird throughout the time the tag was working.
   2. Use Google Earth to get the longitude and latitude of a representative spot in the bird's wintering and breeding grounds.
   3. The date range should be the same as the date range for which bird data was collected.
8. Using your spreadsheet program, make a line graph showing the bird's temperature, the temperature at the breeding grounds, and the temperature at the wintering grounds. Tip: You might need to edit the data to focus in on only dates where data was collected for the bird.
   1. Temperature should be on the y-axis, and the date should be on the x-axis.
   2. There should be a total of three lines on the graph: one line each for the temperature at the bird's location, the wintering grounds, and the breeding grounds. The line representing the temperature that the bird is experiencing will overlap with the other two lines when the bird is at either the wintering or breeding grounds.
9. Print out the graph and, below the x-axis, label the range of dates that represent the bird breeding, migrating, and wintering.
10. What temperature range does the bird experience? You can determine this by looking for the highest and lowest temperature points on the line representing the bird's temperature.
11. What is the temperature range in the wintering location? What about the breeding location? How do the two compare? How do they compare to the temperature range experienced by the bird?
12. Repeat steps 5–11 for at least two other good migration tracks.
13. Based on all the graphs, what is the temperature range for the species?
14. Based on your analysis, do you think temperature plays a role in this bird species' migration? If so, what is the role?
15. If you write up this project for a science fair or school project, don't forget to credit the original authors of the Movebank data set!

Variations

• Compare the Movebank temperature data for several species of birds. Do different species have different temperature tolerances? Can you draw any correlations between physical features of the birds and the temperature ranges in which they live?
• Extrapolate how climate change might affect the migration of your bird species. You'll need to do some research about the various climate change models that exist and use them to predict future temperatures at the birds' breeding and wintering grounds. One place to start gathering information about climate change models is the United States Environmental Protection Agency's webpage about Future Temperature Changes.

• For more science project ideas in this area of science, see Zoology Project Ideas.

Credits

Dr. Roland Kays, Dr. Stephen Blake, Sebastian Cruz, Dr. Wolfgang Fiedler, Dr. Bart Kranstauber, Carolina Proanio, Rolf Weinzierl, Dr. Martin Wikelski, and the MIGRATE NSF RCN, in conjunction with Sandra Slutz, PhD, Science Buddies

Last edit date: 2011-02-02 10:00:00