My old Tigger (sadly passed away now) used to sit and watch our clock, which is one of the synchronized type, when it turned itself forward or back to fit in with daylight saving hours - it used to make a bit of a buzzing noise when it did it, which probably woke him up (he used to sleep in the same room) and he would sit absolutely bolt upright in front of it, staring at it hard. And then when it stopped, he would get up, and go back to bed. The hour change this weekend reminded me of that.