On the power of submitting more to eBird

Drew WebereBird, Science2 Comments

Tim Schreckengost and I spent several hours this morning walking around Toftrees in search of sparrows and any lingering birds that hadn’t been scared south by the snow. I try not to set expectations too high on a cold, snowy morning like today as so was pretty happy with the 28 species we saw. We saw lots of sparrows- American Tree and White-throated Sparrows and Dark-eyed Juncos were the most common, but the best was probably an Eastern Towhee, a hard to come by bird in mid-December. Another birder, Joe, also managed to find an Eastern Phoebe and a Gray Catbird, two other good birds for this time of year.

I was interested in looking at the seasonal occurrences of some of these sparrow species in eBird so I initially looked at their frequency in Centre County. As eBird describes it,

“Frequency” is the percentage of checklists reporting the species within a specified date range and region. This is the most conservative way of displaying the eBird data. For example, when looking at data from across North America we learn that the Yellow Warbler is reported on roughly 25% of checklists during the week starting 15 May. In contrast, the Cassin’s Sparrow is only reported on .1% of checklists from the same region and date range.

The first thing that really jumps out is that this graph is crazy! The lines jump around so much that it is hard to see more than rough trends of what the birds are doing.

So why does it look like this? The answer lies at the bottom of the chart, where it shows the total number of checklists submitted during each weeklong period. Most weeks saw somewhere between 35 and 200 list submissions which is not very much if you consider this is all checklists from 1900-2010.

sparrow frequency- Centre County

sparrow frequency- Centre County

Next, I pulled up the same graph for the entire state of Pennsylvania. Take a look- the lines are much smoother, the trends are much clearer. The reason is that the number of checklists for the entire state average somewhere between 1000 and 4000 for each weeklong period. From these images it is pretty clear the advantages of having a large number of checklists for eBird to analyze.

sparrow frequency- Pennsylvania

sparrow frequency- Pennsylvania

So the take home message from this post should be obvious! Each checklist you submit to eBird is valuable, whether you are seeing lots of great birds, or just the everyday feeder birds in your backyard. Making an account is easy, submitting checklists is even easier and it gives you access to all sorts of great maps and graphs.

So, do you enter all your bird sightings into eBird? Why or why not?