I was rather confused by the name you were given, as the result through Yahoo! Korea's online dictionary has nothing to do with birds, and the term doesn't show up in the online dictionaries offered through Naver or Nate.

I think I have it figured out, though! Parsing the word into its component parts gives "참" and "세", with the former often used with the connotation of "true" or "factual" and the latter … well, I wasn't that sure. However, I got lucky while looking up bird names in Korean and I think the person who wrote out the name for you either spelled it wrong or unclearly, as it should be 참새 instead of 참세.

참새목 is the Korean word for Passerines (Passeriformes order in the Linnean classification system, formerly known as 'songbirds'). Unfortunately, this is the largest grouping of birds, but I got lucky by going back to Naver and trying 참새. Turns out that it means 'sparrow'. And, to get back to the use of 참 to mean 'new', within the order Passeriformes is the family Passeridae — known as the Old World Sparrows or True Sparrows. (Interesting how that distinction crosses the language divide.)

There are five genera in the family that live in Korea, with Passer the only with species that include 'sparrow' in the (English) common name. Those particular species are Passer montanus saturatus (Eurasian Tree Sparrow), Passer rutilans rutilans (Russet Sparrow / Cinnamon Sparrow), and Passer domesticus domesticus (House Sparrow). The bird in your photo is a juvenile, which makes it hard for me to narrow things down to the particular species, but the (male) Russet Sparrow seems to have less black on its throat than the other two species, while the (male) House Sparrow has a patch of gray on the forehead that I didn't spot in your photo.

No idea how common any of those species are, which would also influence the likelihood of encountering one over the others. I'll go out on a limb (no pun intended) and say it's a Russet Sparrow. I'd be more than happy to be corrected by someone more knowledgeable though!

That was probably one of the more interesting 60 minute stretches I've had over the last few days, so maybe having to look the information up for myself worked out for the best! Funny, too, that the word verification for this comment is 'pretend' — as I'm going to pretend like I know what I'm talking about and hit the send button now.

Also, the old map of Seoul is awesome. I can see the older name for 북한산 – 삼각산 (三角山) – posted at the very top, which is rather neat. The Hanja for "Han River", by the way, is 漢江. It's hard to make out some of the characters on the image you posted, but hopefully that will help if you have a larger-sized version to consult! 🙂