For me, the first sign of spring is when I’m walking around and start seeing thin filaments everywhere — the little threads of silk left behind by traveling spiders. This year the first delicate threads spotted were on campus, draped over the metal signposts around the parking lots. They’re all webbed with criss-crossing strands!
I didn’t see the spiders there, not yet, just these traces. From past experience, those signs are often populated by Theridion, so I’ll keep my open for the first appearance of the little guys.