HokkaidoHachi · Hokkaido, JP · Gear · Aug 21, 2026
Mouse guards — when do they actually go on, and do mice really chew through the plastic ones?
Fourth year in Hokkaido, where autumn arrives early and hard. I lost a colony two winters ago to mice — found the nest in spring, a fist-sized hollow chewed through two combs, everything soaked in urine. Not repeating that.
Question one: timing. My instinct says guards go on when nights get cold enough that the cluster pulls up off the floor and stops guarding the entrance — for me that could be mid-September. But I've also read 'before first frost' and 'when you see the first mouse droppings' which seems... late?
Question two: I have the cheap plastic guards from the co-op and a strip of metal queen excluder someone recommended. A club member insists mice gnaw straight through plastic guards over a winter. True, or is he selling me on unnecessary metalwork? The plastic ones were certainly cheaper.
#mouse-guards#winter-prep#entrance#hokkaido
▲ 7 votes💬 4 replies✅ Solved
4 replies
QuebecBees · Aug 21, 2026 · ✅ Accepted answer
Quebec, so we share a winter. Your instinct is exactly right: the guard goes on BEFORE the cluster abandons the entrance — a mouse that gets in on the first cold night settles in for the season, and droppings mean you're already too late. I put mine on when overnight lows hit low single digits, mid-September some years. Your club member is right too: mice absolutely gnaw plastic, I have three guards with neat tooth-holes to prove it. Metal only — the excluder strip works well, or punched metal guards with 9-10mm holes. Bees pass (minus the odd pollen load), mice don't.
VTBeeHannah · Aug 21, 2026
Seconding the timing warning from experience. Vermont, last year, I put guards on in mid-October feeling all organized — spring revealed a mouse had beaten me by weeks. It had eaten a grapefruit-sized cavity in the outer combs and the smell was unforgettable. The colony survived, angry and cramped. This year: September 15, in my calendar, with an alarm.
AlpineCarnica · Aug 22, 2026
Metal, always, and check them monthly through winter — snow piling against the entrance can push a guard loose, and I've had a shrew slip a bent one in Tyrol. Shrews are the sneakier enemy at altitude, they fit anything over 8mm. If your winters are as hard as ours, that queen-excluder strip at 4-and-something mm is honestly the safest gauge there is.
HokkaidoHachi · Aug 22, 2026
Decided: metal excluder strips on all four hives, cut this weekend, installed mid-September when the lows drop. The plastic ones can retire to holding open the shed window. Thank you QuebecBees — 'droppings mean too late' is the sentence I needed.