In June this year I was in Alberta, visiting family, going to Women's World Cup games, and, of course, birding. I have birded in the summer in Alberta before, so I had a relatively short list of target birds, some of which meant going north to the boreal forest. After doing research in eBird and getting advice from a couple of local birders, I went to Sir Winston Churchill Provincial Park, which is an island in the lake Lac La Biche, connected to the mainland by a causeway. I booked a campsite and headed there with great anticipation, and I was not disappointed. It is a birder's paradise, at least in June.
One of the main targets here was Connecticut Warbler. I didn't know much about this warbler other than it's hard to find. It skulks around on the ground in forest with dense undergrowth. I had looked at photos and had a mental image of a bird with an olive-green back, yellow underparts, a gray hood, and distinct, complete, white eye-ring. One had been found along a trail called the Boardwalk Trail. On my second pass along this trail, I found it - a warbler with an olive-green back, yellow underparts, that gray hood, and the distinct eye-ring. It was making a soft chipping sound as it foraged down low in the undergrowth. It was carrying food, presumably for a nearby nestling. This was fortunate, since birds are reluctant to go to their nests if they know they're being watched, and therefore allow you better views and an opportunity for a photo.
Once I had the photo, I left the bird alone, and happily checked the bird off my mental list of targets.
A few days later I posted a note about my trip to Lac La Biche to the Albertabirds discussion group, with links to some of the photos. One person wrote back to me and kindly pointed out that this bird was NOT a Connecticut Warbler, but the smaller, similar Nashville Warbler. The biggest difference is in the throat - the gray hood of the Connecticut Warbler extends down to the breast, whereas on the Nashville, the throat is yellow.
Well, that was embarrassing.
I've been birding long enough now I shouldn't be making such mistakes. I have excuses - I'd never seen a Connecticut Warbler before, I wasn't expecting Nashville - this was the very western edge of its range and they are not commonly found in Alberta. I've seen Nashville Warblers multiple times, but the possibility didn't even cross my mind. What I found was what I was looking for. I was in a place where Connecticut Warblers had been reported, and I found a warbler that fit my mental image, however poorly constructed that was.
It happens all too frequently. Once you see something, convince yourself that it is what you think it is and apply a label to it, it can be very difficult to view that object in any other way. It applies not just to birds, but to many aspects of life - politics, religion, and so on. There are probably whole books on the subject. This is just one example. I wanted to write about it partly as a reminder to myself to check my facts more diligently, and keep an open mind. I hope any readers will find this example useful too.
As a footnote - I went birding north of Edmonton a couple of days later with a local birder. We found several real Connecticut Warblers, of which I was able to get a blurry photo of one. Had I known then that the Nashville Warbler photo I had was not a Connecticut, I would have tried harder to get a photo with the Connecticut Warbler in focus!