"With all the terrible things going on in America right now — and you know exactly what I’m fucking talking about — the thing that drives me the most crazy are the people who see all this awful stuff happening and they still flip out over the little things. My biggest pet peeve in America today are people who see all this horrible stuff going on and yet they still overreact to shit that just doesn’t matter."
— Anthony Jeselnik
Regular readers know that I no longer log my avian observations into eBird, but I do occasionally browse it for recent sightings. After Sunday's fantastic warbler outing, I did take a peek to see what other birders were reporting at the Pheasant Branch Creek Corridor. This can help me further appreciate the level of diversity on a given day by checking for species I might have missed. Sometimes, though, a species on someone’s checklist raises an eyebrow. This is one of those stories — and all names have been omitted to protect the inexperienced.
On one particular checklist, the moment I saw Louisiana Waterthrush (LOWA) on it I knew it was likely a misidentified Northern Waterthrush (NOWA). I knew this from what I know about this species' phenology and distribution. When one considers summer/fall departure dates for LOWA (July into early August) — and the fact that Wisconsin is the limit of its northwestern range — the likelihood of a LOWA being here right now is astonishingly low, nearly zero. When observing a waterthrush in Wisconsin during fall migration, you’ve got to be careful about using superficial non-diagnostic field marks that do not a LOWA make. Thus, a September 17th LOWA report was met with great skepticism on my behalf, and when I saw the photograph, I was certain of the errant ID.
Consider the above LOWA range map. Because a warbler can fly 200 or so miles in a single night of migration, the entire Wisconsin population can vacate the state in a matter of a week or two. For what it's worth, how many September/October LOWA records have been reported in the Dane County area? Just one ... from 1934 — this is an excellent data-point for hypothetical likelihood:
I’m pretty cautious even during spring migration unless I hear their diagnostic songs.
Both waterthrush species can:
1. Have throat markings.
2. Have a long or short appearing supercilium varying in width.
3. Show pink-colored legs (sunlight).
4. Show brown-colored legs (dirty).
5. Render a yellow or white tint on the breast, belly, and throat (ground lighting).
6. Have strong or weak breast/flanking stripes.
7. Bob/pump their tail in every-which direction possible.
None of the above features are diagnostic but can be used to help build a case for one of the two species. Whenever I’m dealing with a non-singing waterthrush, I initially check for:
1. Tail projection length (not always easy to see, but LOWA’s is quite short).
2. A supercilium that appears whiter than the throat and/or flank color.
3. And then some of the other above features.
Most images © 2023 Mike McDowell
If I'm simply unsure, then I don't nail it down to species "waterthrush sp." is good enough.
There are many dimensions to making an accurate field identification and for many birders the entire endeavor is simply about visual field marks, even less about behavior, and generally nothing else. But it can be very important to consider things like range, habitat, historical records, and phenology (time of year). This, in my view, is a part of the disconnect that some birders have with fully appreciating an organism and its natural history versus simply looking at pretty things. To be sure, there isn't anything wrong with the latter, but maybe don't commit to the identification. Getting an identification wrong isn’t going to bring on a Spanish Inquisition, but if you want to up your avian field identification kit, I encourage you to apply knowledge beyond avian topology.