Larger traps will work, but if you have no plans to go trapping and want something to carry with you, then snares like those mentioend by mtnlvr68 seem like a good idea. Snares weight as much as the length of wire and little more and are easy to stick almost anywhere.

In theory, to catch birds, you can use 4-8 snares attached to two pieces of wood, attached to and perpindularly bisecting each other. Attach the snares to the ends of the wood, lay out the loops to form a circle, and spread something the birds will want in the middle. I'd try it out, but it's just not going to happen in my area of Manhattan.

I have some snares in my BOB that will hopefully never be used.