“Incidental” sounds right for the eBird list type. If birdwatching wasn’t your primary activity that’s the one to use.
On the duck, if you think there was a fair amount of mallard going on, “Mallard (domestic type)” is what I would probably use. But “duck sp.”, maybe with some additional text explaining things in the observation detail, sounds perfectly fine to me. It’s really up to you. In general I like to make my checklists as specific as I reasonable can, but I don’t know much about domestic ducks, so I don’t stress about that stuff.
Good call on being careful with taking Merlin Sound ID’s suggestions as gospel. Today I was hearing a bird singing that I kind of thought sounded like a house wren, but also might have been a warbler. (There are a lot of new songs being sung these days with the arrival of spring, and I’m kind of rusty.) I tried Merlin Sound ID on it, and it suggested yellow warbler. But when I got a look at the bird it was indeed a house wren.
I think that’s probably a Black-headed Gull in the back. The foreground bird is interesting; the dark mantle makes me think it’s likely either Greater or Lesser Black-backed Gull. The leg color looks better for Greater.
Size-wise it’s tough for me to tell; I don’t have a lot of experience with relative sizes of these species. Lesser Black-backed Gull is the only one of them I’ve ever seen in person, and that was a single individual seen on a couple of different occasions at some distance.
Sibley gives the following lengths:
BHGU: 15.7″
LBBG: 21.7″
GBBG: 28.7″
So I guess I have to ask myself, does that foreground bird look like it’s 13 inches longer than the background bird? Or only 6 inches longer? I think I’m leaning toward GBBG, since if its head weren’t tucked in I suspect it would look a lot bigger than the COGU. That plus the leg color isn’t enough for me to feel like it’s a slam-dunk, but I’m at least leaning in the GBBG direction. I wonder if there are any photos that show the foreground bird better. It would be interesting to see the extent of dark streaking on the head and nape.
Anyway, I knew that both of the black-backed species were potentially present in @seeseagulls’ vicinity, but hadn’t seen one show up in their blog before. Cool!
