|Two Evening Grosbeaks from northern Utah, where Type 1 dominates but Type 4 has also been recorded.|
1) Record the birds.
The first step is to get audio recordings of Evening Grosbeaks calling. A lot of people get turned off of the idea already, but this is actually quite simple. Most birders are already carrying smart phones, and there are many free apps for recording sound snippets. I used an app called "ACR" when I had an Android phone, but anything that lets you record sound will work. Something most birders don't even think of is that almost all modern cameras can record video, and this is an equally effective way to record sound. Of course, a nice shotgun or parabola mic is ideal, but if you can make a short video with your phone or point-and-shoot camera, that will be enough to identify the birds. The software we'll use in the next step is very versatile when it comes to file formats. It helps to know where on the camera or phone the microphone is located, and point that in the direction of the birds. It might not be the same side of the device as the camera lens!
2) Import the sound into audio editing software.
I recommend using Audacity: it's free, powerful, available on all common platforms (Mac, PC, etc.), and pretty straightforward to use. Raven is another great alternative, with the only weakness I know being that the latest free version isn't compatible with the latest Mac operating system. In most cases you will be able to simply drag and drop your audio or video file onto the icon for your audio editing software to open it. If the software refuses, I find a "force open" usually works: for some uncommon video formats, I have to hold "option" plus "command" on my Mac when dropping the file on the icon, and then it works.
|Here's a pretty typical example of some Type 1 Evening Grosbeak calls that I recorded in my yard and then visualized using the free program Audacity.|
3) Make a sonogram.
Again, this is not as tricky as it might sound. If either of the above two programs opens your file, you'll see the sonogram right on your screen. Adjust both the vertical (frequency) and the horizontal (time) zooms until the sonogram looks about right. Then use a screen grab to save the image to your desktop. In Macs, you can do this by typing the "command"key, shift, and the number 4 at the same time, and then drawing a box around the area of interest. In PCs, you can use Alt + PrintScreen. (You might need to then paste into an image editor like Paint to see the image, then save it.)
4) Match the sonogram to the call type.
Unlike Red Crossbills, Evening Grosbeaks have only about five distinct call types. Download this paper, Sewell et al. 2004, and simply compare your sonograms to the examples in Figure 1!
5) Enter your data in eBird.
Here's your chance to really contribute to science: enter your sightings in eBird, and be sure to specify the call type and include a link to your sonogram. Keep in mind that in most areas, you'll have to add the call type to the list manually, by clicking "add species" and then searching for "Evening Grosbeak," and selecting the relevant type. Evening Grosbeak call types are sorely under-represented in eBird, but together we can fix that!