Uh-oh. A little bit–ok, A LOT–of eBird geeky stuff lies ahead…
I spent the last few days wrangling some eBird data for the state of Ohio. I processed year list data for 10 individual years, 2003 through 2012. What comes next is me…tinkering with data I downloaded from http://ebird.org on 6/26/2013. eBird is a Citizen Science online project containing over 100 million bird sightings worldwide. And it is growing every day. eBird allows ordinary birders to enter their bird sightings online and stores them in a database. I downloaded data from this database into spreadsheets to create the final report available as a free download below in .PDF format.
A total of 32,307 checklists were submitted to eBird for the state of Ohio in the 5 years 2003 through 2007 representing 339 species. For 2008 through 2012, 97,837 checklists were submitted to eBird for the state of Ohio and a total of 357 species were recorded. The combined total number of species for the 10-year period 2003-2012 was 368 species of birds.
Of the 368 species, 274 species were recorded in each of the 10 years between 2003-2012. In fact 28 species were reported in every week for the entire 10-year period.
Of the 368 species reported, 241 showed an increase in % of checklists. In other words, about two thirds of these species were reported on a higher proportion of checklists in the second 5-year period than in the first 5-year period. Some of this may be attributed to the large increase in the number of checklists between the periods. But 127 species showed a decrease despite three times the number of checklists in 2008-2012.
The 10-year Difficulty Code is a number derived using the logarithm of the percent of checklists for a species for the entire 10-year period. So a Code 1 species is up to 10 times more common than a Code 2 bird. Likewise, a Code 2 bird is up to 10 times more common than a Code 3 bird. That same Code 3 bird is up to 100 times less common than a Code 1 bird. And when “common” is used, it isn’t true abundance. First, frequency of checklists is only the percent of checklists on which a species is checked as seen. Also, this represents what is submitted to eBird. Not everyone uses eBird so the data that exists there is but a sample of reality. Still, over 100,000 checklists represents a body of data that is quite superior to “I am pretty sure there are a lot less Canvasbacks in Ohio. I don’t see as many as I used to.”
I just finished this report and have not had much time to review it yet. But, I was so excited about it that I decided to make it available for others to look at it. I hope you find it as interesting as I did.
Tax Seq: Taxonomical Sequence
2003-2007 Rank: 5-yr ranking for 2003 through 2007
2008-2012 Rank: 5-yr ranking for 2008 through 2012
Chg in Rank: Change in ranking positions from 2003-2007 to 2008-2012
10-yr Diff Code: Difficulty Code for 2003-2012 as reported in eBird % of checklists submitted; 1 is most common; 2 is up to 10x less common than 1; 3 is up to 10x less common than 2, and so on
Species Name: Species Name
2003-2007 % of Checklists: total number of checklists for a species submitted to eBird during 2003-2007 divided by the grand total number of checklists submitted
2008-2012 % of Checklists: total number of checklists for a species submitted to eBird during 2003-2007 divided by the grand total number of checklists submitted
Actual Change: the difference between the two 5-yr % of checklists
% Change: the rate of change as a percentage from the first 5-yr period to the second 5-yr period
2003-2007 Weeks Reported: number of weeks a species was reported in eBird 2003-2007
2008-2012 Weeks Reported: number of weeks a species was reported in eBird 2008-2012
2003-2012 Years Reported: number of years a species was reported in eBird 2003-2012
And without further adieu, here is the report: Ohio Birds 10-year Report 2003-2012