Bird Species List from eBird
Until now, the list of birds in Cesar Chavez Park has been limited to species whose photographs (and/or videos) have been published here on chavezpark.org. That’s well over 100 species; see the Bird List here. But that’s only a fraction of the bird species that have been spotted here over the years and posted to the eBird site maintained by the Cornell Lab of Ornithology. Thanks to birder and bird-ecologist-in-training Dallas Levey, the eBird postings for Cesar Chavez Park from 2006 through early May 2022 are now captured in a four-page spreadsheet, below. Dallas, soon to commence a PhD program at Stanford, has also summarized the data for the birds’ preferred habitat, preferred diet, and preferred foraging method in a set of pie charts, below the spreadsheet. Also added is a chart of relative abundance and a list of the 15 species in the park reported most commonly to eBird. By way of background, this page also includes at the bottom a “Working Species List” spreadsheet that indicates whether the eBird posting includes a photograph, and if so, by whom, with a link to the eBird checklist that contains the item. It also indicates in some cases where in the park the bird was spotted, along with observers’ comments.
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I agree, Peter, with your note of caution with the table of relative abundance table. I should have placed a note there, or better yet used different language in the caption. If I have time, I will compile a subset of lists submitted to eBird from observers that are reliable in their efforts to report every bird species and individual that they detect.
We had the plan to do a systematic sampling of certain areas of the park. This was abandoned fairly quickly due to time and space constraints for area counts and point count surveys, respectively. I will say that after reviewing the data downloaded from eBird and the data in Table 1, I feel relatively good about the 15 species listed there. The order and the relative abundance values may not be exact, but there is likely not an egregious error with any of the listed species there. This is obviously not ideal or scientific, and it is based off of my trips to the park to bird.
I have also wondered how well the eBird data reflects reality.. I know that there exist some papers on the subject, but I don’t have any on hand. It surely isn’t perfect, but perhaps it’s sufficient for these preliminary glances into the diversity of an area.
There’s more work to be done!
“Table 1. List of top 15 most abundant species” must be interpreted with some care. It most likely does not represent the “top 15 most abundant species”, not even in “relative abundance”. Rather, it likely represents only what observers were inclined to report (because that’s only what they saw and of those only what they chose to report) to eBird.
Perhaps the take-away insight provided by the summary eBird data / chart is the question: “How (well, accurately, likely) do these data reflect the true relative (and/or absolute) abundance of the species occurring in Cesar Chavez Park?”