Three billion birds – It’s a big number
A recent report published in the journal Science indicates that there are 3 billion less birds flying around North America today than there were in 1970. Many of these birds are neo-tropical migrants, meaning that they fly south for the winter. Such a lifestyle creates a world of predicaments with habitat loss being an issue for every part of these birds’ journeys. However, loss of food sources from use of pesticides, along with the habitat loss of the food source itself are additional problems. Groups like the Audubon Society provide citizen science data the helps track these changes. Every year across the United States local communities host holiday season bird counts around the new year. In Eugene, the count is hosted by the Lane County Audubon Society. Here are the results from the last count. This is good for our winter residents, but doesn’t help with tracking the migrants. Instead, breeding bird surveys are used, but these require that participants become good listeners for bird calls. Even many avid birders have problems accurately identifying calls of many common species. However, new tools are making this work much easier and more accurate. A free app from the Cornell University Lab of Ornithology and the Audubon Society allows the app user to see pictures and hear calls of all our U.S. species. Additionally, spectral analysis programs like Raven Lite allow users to view the spectral signal of bird calls. Check out my video of the program. Hearing the call and seeing the spectral pattern adds to the ease of identifying the bird or birds making the call. Additionally, Artificial Intelligence (AI) is allowing researchers to record months of calls in the field that then identify the species on the recordings. I am excited to say that I will working on one of these projects this summer at the HJ Andrews experimental Forest in conjunction with researchers (Matthew Betts) at Oregon State University.
Here is one of my recording set-ups with my cell phone and a Rode shotgun microphone. However, the microphone was designed to capture human speech so it it filters out high frequency sounds above 15 kHz. This is fine for recording humans, but not as good for birds and certainly unusable to trying to record bats and other animals that we know or don’t know that emit calls above the best human ears (22 kHz). Better mikes are available but easily cost over $1000.
In the video link you can hear a Bewick’s wren early on as the dominant calling bird followed by the harsher staccatto call of the Steller’s jay. Towards the end there is the solitary note call of a varied thrush.