I am often asked questions about fluctuations in bird populations. The common question is: “I’ve noticed that all my chickadees are gone this year. Are other people seeing this decline?”
Most recently, I was asked about a lack of Belted Kingfishers in southern Maine. It is easy to say that we haven’t seen any noticeable drop in their population but we can use real, publicly available data to see the proof. Below I’ll explain the process and encourage you to try this on your own with any species that you have been wondering about.
The data we will use is available from an online database at eBird.org.This is driven by citizen scientists submitting checklists of what birds they see, where and when.The tools eBird provides are available for anyone and are all free!
To start, go to eBird.org, click on the Explore Data tab, and we will be using ‘Line Graphs’ to illustrate this example. You’ll be prompted to select a species and then click ‘continue.’ You’ll want to adjust the area by clicking on ‘Change Location’ and you can narrow your data down to a state or county level. (Going lower than a county level may not give you enough data to work with). For our Belted Kingfisher example, I’ll narrow down to York and Cumberland Counties to represent “southern Maine.”
The default chart will show you information for ‘all years’, so you will want to restrict that to the current year.
Note that the scale of the frequency on the vertical axis changes on these two charts but overall the frequency (the percentage of total checklists reporting that species) is almost unchanged between the average (first chart) and this year (second chart).
You can download the raw data from each of these line graphs using the “Download Histogram Data” on the right side of each page. It makes for a better comparison if you drop this data into the spreadsheet software of your choice (Excel, Numbers, etc) and create charts there. Here is a graph comparing those two charts we created above:
So, Belted Kingfisher look like they are doing fine in southern Maine! Here is an article I wrote on this same process, focusing on how Blue-gray Gnatcatchers are showing a fairly remarkable increase in the past few years:
-Doug
Meet Doug Hitchcox, Maine Audubon Staff Naturalist
A Maine native, Doug grew up in Hollis and graduated from the University of Maine in 2011. Throughout college Doug worked at Scarborough Marsh Audubon Center and was hired as Maine Audubon’s staff naturalist in the summer of 2013, a long time “dream job.” In his free time, Doug volunteers as one of Maine’s eBird reviewers, is the owner and moderator of the ‘Maine-birds’ listserv and serves as York County Audubon board member and Secretary of the Maine Bird Records Committee.
