Many thanks for all these details, Jim.

My criteria for keeping my own personal yard list are definitely my own. I want to know which birds are using the habitat I provide, not every bird that might pass through the general area.

When I'm listing for ebird or whatever, I do make note of every bird I see/hear, however distant. It's interesting, though, that Cornell encourage us to count every bird, even when it's highly likely to be a repeat. My tendency in those circumstances has been to count the minimum number of birds rather than the maximum, because I have indeed been worried about over-counting. Certainly on the CBCs I've been on, I've been encouraged to count that way to avoid over-counting.

Does anyone know of there are specific criteria for CBCs that differ from those of Cornell?

Louise Rutter

Kirkland

On Sun, Jan 26, 2025 at 12:24 PM via Tweeters <tweeters at u.washington.edu> wrote:

Louise,



Back when I was first starting to use eBird I asked this specific question

about my checklists. Specifically - "when do you report (count) a bird?"

and gave the example of my backyard feeder and the fact that I could

see birds coming and going ... but suspected - highly - that some/many

of them were 'repeats' and had been there as short a time ago as only a

few minutes.



The answer I got was "if you don't know for certain it is the same bird -

count it". So even if you have a group of say 10 finches that are coming

and going from your yard/feeder - the advice is to count them "every time

you see them that you, personally, can't say it is the same bird".

This advice is not just about birds in our backyards. And Cornell

doesn't consider it "over counting" (probably because you will also

miss many birds that might visit your backyard when you do something

as seemingly insignificant as just getting another cup of coffee).

There are similar considerations for 2 or more people all seeing and

reporting the -same- bird ... perhaps even birding together.



So here is my take/interpretation of this advice. As long as everyone is

using pretty much the same methods - it doesn't matter ... because

what the science is about is the changes - over time and even over

relatively long periods of time. Such as from one season to the next or

one year to the next or one decade to the next.

We all know about events such as "irruptions" and "long term trends"

etc.



===> If we have lots of data (reports) then it all averages out in ways

that wouldn't be true for just a few reports (total number of

checklist).



But there -are- lots of checklists being done in all kinds of situations.

So report what you can ID and let the citizen science work out what it

means. Even reports such as "Gull, species" are valuable/useful -

especially when compared to no reports at all?

- Jim in Skagit

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