If you are an experienced backcountry hiker, you probably know how to use a compass to reach a destination. But if you are a birder, you may not have used a compass since your days in the Scouts. With that in mind, here’s a quick primer on how to use a compass or a handheld GPS to help you navigate your transect and mark the locations of singing male Kirtland’s Warblers on a map as you go. 

 

To ensure we will have enough equipment for everyone in a single day, we ask all volunteers to bring their own compass. (The compass must have orienteering lines on the base of the compass housing. These lines will be critically important when it comes to triangulating the positions of singing males.) We ask that you bring a handheld GPS unit if you have one. A limited number of GPS units will be available for volunteers. A GPS app on a smartphone may be used but ONLY if you are certain the phone has GPS capability and you are experienced using your app. (The app must allow for the entering of waypoints and navigating to/from the waypoint by precise distance and direction.) We do not have the time to decide whether your phone has the capability or train you on how to use your app. And if your cell phone should lose power in the middle of a transect, it’s not like you can just pop in two new batteries. 

 

A census organizer will provide you with a map that shows the starting and stopping points of your transect. We try to organize as many transects as possible to run from west to east to ensure the sun will be at your back, but you should not count on receiving one. Oddly shaped tracts require oddly shaped transects. 

 

How to walk a transect with a compass:

First, adjust your compass correctly for declination. As you likely know, True North and Magnetic North are different. We want to use North to navigate but have to adjust the compass to account for the fact that the needle is pointing to Magnetic North. In Grayling, the difference is about 6 degrees west. Check with your route leader to confirm the appropriate declination for your area. Some modern compasses have locks that prevent the bezel (the outer dial) from accidentally being moved once a bearing is set. If you have one of these, know how to change and lock bezel before entering the field.  

 

The next step is to get a bearing—the direction that you will be walking. It would be impossible for you to walk in a straight line over uneven terrain through the dense jack pine without the aid of a compass or hand-held GPS. Determining a bearing and following it closely will help you stay on your transect. Ensuring you stay on your bearing is important because some transects are rhombus-shaped while others will ask you to change direction two or three times. The transect will exit on a road, but not the same one where you started. Don't worry, someone will be there to pick you up.

 

How to determine a bearing: 

Place your compass on the map with the direction of travel arrow pointing in the direction you want to go. 

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Rotate the bezel so that the orienting arrow (the arrow is inside the bezel - not to be confused with the needle) is pointed straight at 360 degrees north. Make sure the direction of travel arrow is still pointing in the direction you want to go.

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Here’s where you add your declination: 6 degrees in Grayling; 7 degrees near Oscoda; 4 degrees in Marquette. 

 

Take away the map and line up the needle with the orienting arrow inside the bezel and - voila! - you have your bearing. Keeping the needle and the orienting arrow lined up, look down your direction of travel arrow; that is the direction you need to go. 

 

Now that you know your bearing, look at the horizon in the direction of your bearing -- if you can. In some census locations, the jack pines might just be short enough that you can pick out a tall tree or other landmark in the distance. You can use that as a navigation aid. Never use anything that is likely to move - like a cloud - as your visual reference. In places where the pines on your transect are too tall you will be forced to rely exclusively on your compass. 

 

If you are a visual learner, here’s a link to a video that might help.

 

How to walk a transect with a handheld GPS

This should be obvious but we feel we should provide this reminder: Make sure the device is fully charged before entering the field and that battery capacity will last at least six hours. Also make sure you have the latest software upgrades. It’s not necessary to load any local topographical maps; it’s not like you’re hiking the spine of the Rockies. 

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Before you get started, you will be given a map with the coordinates of your transect’s starting point. Use your GPS unit to guide you to your staring point. Unless you can walk to your starting point, you will coordinate with others to ride to the starting point.

 

Upon arrival at your starting point, set that location as a waypoint. Then make sure your GPS is registering distances in meters, not feet. 

 

Okay, it’s now time to head out. Let’s say that you are starting on the east side of your transect and know you know that to get to your finishing point you have to walk due west - 270 degrees. Instead of following your GPS on a 270-degree path straight through the woods, you can deviate and may well be forced to if you encounter an obstruction. If you choose to/are forced to veer off course, use your GPS to return to your transect.

 

Do not forget your GPS unit must be set to meters. The census protocol requires you to stop every 201 meters (660 feet) to stop and listen. BUT! When you reach 804 meters you will need to drop a new waypoint/starting point. This is important because your next stopping point would be at 1005 meters, and when you pass 1000 meters, the GPS will begin to count in kilometers. We don't want that! So at 804 meters, drop a new waypoint to ensure you are properly measuring the distance between stopping points. 

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Triangulation

Your ability to triangulate the location of a singing male Kirtland’s Warbler is important to the census for two reasons: 

•If you are in an area with multiple birds, triangulation will help you discern their individual locations.

•It improves the accuracy of a bird’s estimated location. This is particularly important because at the end of your transect you will likely be comparing the locations of birds you counted with those counted by census takers on adjacent transects. The goal of comparing locations is to lower the possibility of counting the same birds twice. Remember, we do not want to risk an overcount. If in doubt, do not count.  

 

You don’t need to know trigonometry to triangulate. But here's what you will need to know:

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1. You must know your exact position on your transect. If you have been walking a transect following your bearing from your compass/GPS unit and stopping at the designated intervals (201 meters apart), you should know your exact location on your map. 

 

At each stop, listen for singing males. In some places you might hear none. In others you might hear many.

 

2. If you do hear singing males, determine the number of singing males, and, using your compass, get a bearing on the position of that bird or those individual birds. See Figure 1. Make sure the length of your line corresponds to the estimated distance of the bird. 

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