Re: [cobirds] Using eBird graphs

Thanks, David!

This is a really helpful explanation.

Gary Brower

Unincorporated Arapahoe County

On Sep 13, 2022, at 4:33 PM, David Suddjian <dsuddjian@gmail.com> wrote:

Hi CoBirders. Sorry for another post from me today, but my summary of Buff-breasted Sandpiper high counts prompted questions about using eBird graphs. I hope this brief summary is useful. Also attached as a pdf. --David

Many eBirders may not be familiar with or even aware of the graph features you can access from Bar Charts. This was how I dove a little deeper into the Buff-breasted Sandpiper (BBSA) story, and a feature I've used to help understand status and distribution in my Bird Bombs.

In Explore, select Bar Charts and then proceed to choose whatever region you are interested in. You can choose the whole state, or individual counties. (Or you may view a bar chart via a hot spot or region you are looking at). You can include multiple counties in one chart, so if you want to look at the Metro area, you can choose those several counties.

https://ebird.org/GuideMe?cmd=changeLocation

When you have a bar chart opened, go to a species of interest and click on the line graph icon to the right of the species name (circled below in Figure 1)

 

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Figure 1. Bar chart for Colorado with the line graph icon circled.

 

Then you will see a line graph showing the species' frequency of occurrence (% of all complete checklists for the eBird week) (Figure 2). Frequency is the default graph that is presented, and it is one of the most useful. It is a linear portrayal of the bar chart image. And there are several other options listed above the chart, presenting different measures (Figure 2). I used the High Count option to look at BBSA, but in general the Abundance graph is very useful for looking at seasonal change and comparing among species. The different measures are defined from a link at the bottom of each graph page. I recommend reading the explanations.

 

<Screenshot (122).png>

Figure 2. Frequency graph for BBSA in Colorado. Note options above the graph.

 

Above each graph are options to Change Species or Change Date (Figure 2). Change Species allows you to switch to a different species, but also to view up to 5 species at once. This is excellent for comparing timing and relative numbers among similar species. Here is a graph of comparing BBSA with some other rare shorebirds (Figure 3). Of these rarer but regular shorebirds I selected, we can see that the AMGP occurs more often than the others, BBSA and SBDO peak earlier and share similar timing, while DUNL is later than the others.

 

 

<Screenshot (125).png>

 

Figure 3.  A comparison of frequency of occurrence for four rare but regular shorebirds.

 

If you Change Date, you have the option to show consecutive years separately for one species. Select a range of years at the bottom of the Change Date screen and choose the start year and end year (up to 5 years) and click the box to show separate years (Figure 4).

 

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Figure 4.  From Change Date you can select different years or a range of years. Click on the box if you want to show consecutive years for one species.

 

Now you can compare BBSA over several years (Figure 5). The graph shows that BBSA frequency is always very low, and that while there is a general peak in late August to early September, each year is a little different where the records fall and the season peaks. The best time seems to be a mere 3-week period at best, most years. Wow there is a lot to learn here.

<Screenshot (127).png>

Figure 5. BBSA frequency over five years 2015-2019,

 

David Suddjian

Littleton CO

dsuddjian@gmail.com

 

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<A Quick Look at Using eBird Graphs.pdf>