The very last data-quality step: Help us check Priority Block lists!

By Nick Anich December 2, 2021
Ruby-throated Hummingbird Archilochus colubris

We have arrived at the final step of data review for Wisconsin Breeding Bird Atlas II: review of the species lists for Priority and Specialty Blocks.

We have gone through many other vetting steps (screening for breeding codes, dates, and map review) and this is a final check to make sure we’ve caught everything (and catch any errors we may have made in our bulk processes!).

The goal of this process is to make sure we’ve done our best to have each Priority/Specialty Block list best reflect the species that breed there. Remember, coded species count, and species without a code (or F – flyover) won’t count as breeding in the block.

At this stage, we are looking in Priority/Specialty Blocks for 2 things: uncoded species that need a breeding code, or coded species that should not have a breeding code.  We have prepared several spreadsheet files for each block which highlight the few species you need to focus on when considering a change in code status.

We are looking for your assistance in checking the local areas you know best — we’re especially interested in review from Principal Atlasers who covered these blocks best.

Please check out the blocks in your area you are most familiar with.

If you’re interested in helping, join us for a live walkthrough of this process Dec 12 from 7-8 PM.

Want to get started now? We’ll explain how. Here are the basics:


1. View the spreadsheet files here
2. Look for records that might need a code added for each block
3. Look for records that might need a code removed for each block
4. Email us with details so we can investigate and fix if appropriate



Step 1: View the spreadsheet files here

There are 4 files for each Priority/Specialty Block, in folders by county. If you do not see files for a block, there are no records that need to be coded up or coded down.

  1. Summary for code up check
  2. Details for code up check
  3. Summary for code down check
  4. Details for code down check

You might find it handy to open up the Atlas Interactive Map to explore block boundaries and habitats if needed, as this process can involve considering which habitats are in each block.

Step 2: Look for records that might need a code added for each block

Recall that species should get a breeding code if we think they were probably nesting in a block. This step is a check where we look at a list of species that have no codes but might need them. We have screened it so you only have to look at a small list of the most likely species

The first file to look at is the one called YOURBLOCKNAME_CODE_UP_CHECK_summary.

This file only contains species that were reported in your block and do not have a breeding code. They are sorted by the most likely to need a code.

If you see no species that strike you as suspicious for breeding in the block, head to step 3.

If you want to find more details on some of those records, open up the companion file called YOURBLOCNAME_CODE_UP_CHECK_details. This will have the more details on the records in the other file. We can pull some of them up, look at dates and locations, follow a link to the eBird checklist if needed, and try to figure out if any of these need a code.

Let’s look at American Goldfinch. The dates and locations certainly seem reasonable so this is a species we’ll want to report to Atlas Central to get an H code.

But other species that sneak into the B window from the first spreadsheet probably aren’t slam dunks. Looking at the Alder Flycatchers, we see that the date is 6/3 and that is the only record for the block, so we conclude they are late migrants. Similarly, we look at the Cliff Swallows and determine they were over water at a location with no habitat for nesting, so decide they should not get a code. Use your local knowledge to make the best decisions you can. If you are on the fence, you could pull up data in regular eBird and look at the dates the birds were found (especially June and July) for the surrounding area). Some birds in June and July might look good at first glance but upon further inspection, if that’s the only record in a priority block, maybe they were not local. Or perhaps the checklist that is recorded here was actually a 15-mile traveling count. On the other hand, maybe there is a very common species you are positive bred in the block but the only time it was reported was in the last week of May in the E period, that could be an instance where we might want to put an H on it on that date. In general, the B period is safer than the E period, but here your local knowledge carries significant weight.

Step 3: Look for records that might need a code removed for each block

In this step we are looking at all the coded records in a block and in particular focusing on ones that may NOT deserve a code – specifically records that never are coded within the B window, or birds that were only reported once or twice in a block.

Now, open the file called YOURBLOCKNAME_CODE_DOWN_CHECK_summary.

Similar to the other screen, this involves some judgement calls. The B window can be tight for some species, so it may not be a deal-breaker to have a species coded outside this window, but it’s worth examining. Here you can see the number of total occurrences (uncoded and coded) of a species in a block, the first and last date a species was coded, and the number of days present (calculated off the first and last date – even though those mays be different years). Similarly, most blocks will have a few species only coded once. Maybe it’s a species that’s hard to detect or a habitat not visited often. But maybe it’s not a very likely species for the block. Again, use your knowledge of the block to scan the species for your block. Overall, we’re not trying to be super picky at the expense of species that likely nested here, but these screens are a good way to find the species you should be skeptical about.

To dig into the specific records, pull up the companion file called YOURBLOCKNAME_CODE_DOWN_CHECK_details. Here you can view more details on these records, visit the checklist link, see the location and comments and try to determine if these species deserve a code or not. The only dates for Red-tailed Hawk and Northern Harrier are a bit late – does the habitat look good in this block? How does the habitat look near the locations where Orchard Oriole and Yellow-billed Cuckoo were reported?  The date for Hairy Woodpecker may be a bit late too but that’s a fairly common species, so we may give that one a bit more leeway.  As far as the blue species above, even though they had few records in the block, the dates look very reasonable for the most part – maybe the habitat and details should be checked for Mourning Warbler as a possible late migrant.

Step 4: Email Nick at with details so we can investigate, fix if appropriate, and check off as complete
When you email:
1. Let us know which blocks you checked (or which counties) – including blocks where things looked fine.
2. Tell us if you would recommend changes for any species in any blocks.
3. If changes are needed, copy and paste the relevant checklist URL for records that should get a code (e.g. or let us know there are multiple block records that need to come down
4. Provide context about why species is or is not a local breeder
5. If you have multiple corrections, please send them in the same email rather than multiple emails

That’s it! Thanks for helping us catch data quality errors for the atlas.


*FYI — continue to ignore the following species for this process. (These should NOT be in the spreadsheets anyway). Observed and Possible codes for summer records will show together on the final product for this set of species.
Spotted Sandpiper
Laughing Gull
Ring-billed Gull
Herring Gull
Great Black-backed Gull
Forster’s Tern
Common Tern
Caspian Tern
Double-crested Cormorant
American White Pelican
Turkey Vulture
Bald Eagle
Great Blue Heron
Great Egret
Snowy Egret
Cattle Egret
Black-crowned Night-Heron
Yellow-crowned Night-Heron