Having compiled the weekly observation data to plot the growth of eBird usage in previous posts, we will now look at the composite weekly and monthly time series.
I took the median number of observations submitted to eBird for each week from 2007 through 2012. I chose the median over the average to dampen the effect growth has on the distribution of this small sample size (n=6).
Below are four graphs; two for the weekly data and two for the monthly data. The first in each set is a time series plot and the second is a ranking plot in descending order. (left click to enlarge)
I’m not sure what real conclusions can be made but speculations come easy. I’ll leave those to you and only note, that while May was no surprise, September would not have been my guess for having the lowest number of records submitted.
Tom Auer has been looking at the same data for Rhode Island over on his blog – here.
He makes, what I think, is an important point:
“One of the goals of eBird is consistent sampling effort. This is why all checklists matter as long as they’re complete, including the five minute backyard counts in urban areas. If the only checklists that were ever submitted were from birding hotspots at the peak of migration when birders were chasing vagrants, we’d have a very skewed view of the bird world. Ideally, the number of checklists submitted by week would be the same throughout the year.”
So – get out there in September and October.
Also while you’re at it, see if you can’t make it over to Wheeler, Gilliam or Baker Counties, they have the least number of records submitted – I’m pretty sure there are birds there. In keeping with eBird’s call to “bird the road less traveled” we’ll dive a little deeper into the county data in a future post.