Prairie Warbler
Setophaga discolor

Early records for Illinois in eBird
as of the July 2024 release

While working on the Spring 2024 Illinois-Indiana seasonal report for North American Birds, I noticed that support for many/most/all of the earliest Prairie Warbler records was minimal. Here are the 10 earliest eBird records (in the July 2024 release) along with comments.

1. 12 March 2007, https://ebird.org/checklist/S2833568
   There are no comments in the checklist to support this sighting, and there are no reviewer notes.
2. 18 March 2012, https://ebird.org/checklist/S10201663
   This is a heard-only record. I think perhaps that it is likely correct, but it is about two and a half weeks ahead of the record early arrival date and three weeks ahead of the average arrival date (as determined at the time of the sighting), making me think that the observer did not realize how very early this observation was (the observer's comment is that "it is a bit early"). The observer Tyler Hallman was in a master's program in zoology at Southern Illinois University at the time of this sighting. He subsequently did his PhD in wildlife science at Oregon State University and now in an academic position at Bangor University in the United Kingdom. The reviewer notes imply to me that the full checklist comments were added following a prompt by the reviewer.
3. 2 April 2024, https://ebird.org/checklist/S167080081
   There are no comments in the checklist to support this sighting. The reviewer notes this as not an exceptional record.
4. 3 April 2020, https://ebird.org/checklist/S66577053
   There are no comments in the checklist to support this sighting. The reviewer notes this as not an exceptional record.
5. 5 April 2020, https://ebird.org/checklist/S66685636
   This one is strange. There are no comments in the checklist to support the sighting. The review record shows the sighting being questioned by a reviewer, followed the next day by the species being changed from Prairie Warbler to Eastern Meadowlark, and then the following day the species changing from Eastern Meadowlark back to Prairie Warbler. What is happening with these species changes and why is there no review associated with the change back to Prairie Warbler?
6. 6 April 1986, https://ebird.org/checklist/S21716683
   This record of Doug Robinson's references his 1996 Southern Illinois Birds book. I am happy with this being considered valid, but why is there no record on any eBird review? Does 6 April not trigger a filter?
7. 6 April 2019, https://ebird.org/checklist/S54620153
   There are no comments in the checklist to support this sighting, and there is no record on any eBird review. Does 6 April not trigger a filter?
8. 7 April 1999, https://ebird.org/checklist/S16252981
   This checklist of Keith McMullen's appears to be an upload of an AviSys checklist. The "/h" notation in the comment is an AviSys "heard only" indicator. Keith also adds a "/?" meaning perhaps he had lingering questions about the sighting? There is no eBird review.
9. 7 April 2019, https://ebird.org/checklist/S54665582
   There are no comments in the checklist to support this sighting, and there is no record on any eBird review. It seems 7 April does not trigger a filter.
10. 7 April 2000, https://ebird.org/checklist/S16254905
    There are no comments in the checklist to support this sighting, and there is no record on any eBird review. It seems 7 April does not trigger a filter.

Here are totals of confirmed eBird records for slightly later dates.

Based on published sightings in Illinois Birds and Birding and in Meadowlark during 1985 to 2021, the average arrival date for Prairie Warbler over that period of time is 10 April, the median arrival date is 11 April, and the earliest is 3 April. This shows that anything from 11 April or so or earlier is an early record. Here are the dates of the earliest Prairie Warblers.

1. 3 April 2020 -- Rhonda Rothrock record (#4 above), included by me in the Spring 2020 Meadowlark report.
2. 5 April 2020 -- Wayne Ryan record (#4 above) from Sangamon County, and so the earliest central Illinois arrival record. I included it in the Spring 2020 Meadowlark report, though looking at it now, perhaps that wasn't wise to do.
3. 6 April 1986 -- This is the earliest date appearing in Dave Bohlen's The Birds of Illinois; it references Doug Robinson's record (#6 above). The second earliest date in Bohlen's book is 13 April (from 1984).
4. 6 April 2019 -- Craig Taylor record from Hardin County (#7 above), included by me and Tyler Funk in the Spring 2019 Meadowlark report.
5. 7 April 1999 -- a Keith McMullen record from Union County noted by Paul Clyne in his Spring 1999 Meadowlark report as the second earliest Illinois arrival. This is sighting #8 in the eBird listing above.
6. 7 April 2000 -- a Keith McMullen record from Union County, included by Paul Clyne in the Spring 2000 Meadowlark report.
7. 7 April 2019 -- Michael Morin record from Menard County (#9 above), included by me and Tyler Funk in the Spring 2019 Meadowlark report.
8. 8 April 2015 -- a record from Champaign County with Nicolas Sly, Dallas Levey, and Jason Newton as the observers, included by me in the Spring 2015 Meadowlark report.
9. 8 April 2020 -- Judy Groskind record from Crab Orchard NWR, including by me in the Spring 2020 Meadowlark report.
10. 9 April 2011 -- a Keith McMullen record from Massac County, included by me in the Spring 2011 Meadowlark report.
11. There are six or more records on 10 April, with at least one from each of the following years: 1988, 1992, 1995, 2001, 2005, and 2010.

Based on all this, I am thinking that any Prairie Warbler observation in the state on 11 April or earlier should be flagged for review. I suggest also re-reviewing (or reviewing for the first time, as appropriate) the records from 11 April or earlier.