Tropical Audubon Society

South Florida’s Voice of Conservation

To examine if weather could have played a role in the occurrence of this bird, I looked at weather maps at the NOAA/Physical Sciences Division Climate Analysis and Plotting Tools website. The link is https://www.esrl.noaa.gov/psd/cgi-bin/data/getpage.pl . (I am an atmospheric sciences professor. My email is sbf1@psu.edu)

I have attached 5 weather maps (see the above eBird link or go to https://ebird.org/checklist/S62795465) showing wind vectors for the 925-hPa surface, which corresponds to a height of about 800m above the surface. These maps are for 12/27/2019 at 18z through 12/28/2019 at 18z. (Note that 5 hours need to be subtracted for the local Florida time, i.e., 18z corresponds to a local time of 1:00pm.) As can be seen, the winds are favorable for a vagrant White-cheeked Pintail from the early afternoon of 12/27 and the entire day of 12/28. The wind vectors are oriented westward from the Bahamas toward the southern tip of Florida, and farther to the west, the winds are oriented northwestward in a direction parallel to the southwest coast of Florida. Therefore, if the White-cheeked Pintail is indeed a natural vagrant, and it flew parallel to the local wind vector, it could have flown westward from the Bahamas to the southern tip of Florida, and then parallel to the southwest coast of Florida, coming down in Naples.

The wind direction was less favorable on the morning of 12/27, since the wind was westward. As a result, the bird would have had to cross all of southern Florida to reach Naples. On 12/26, the winds were much weaker. The only other date with moderately strong westward winds in December was 12/12, However, to reach Naples on that day, the bird would have had to fly cross all of southern Florida, as on the morning of 12/27. Therefore, if this bird is a natural vagrant, as indicated above, it likely arrived in Naples on the afternoon of 12/27 or on 12/28, 1-2 days before it was first seen.

Also, note that there are higher resolution maps at the NOAA/PSD. However, those maps are not yet available.