I've noticed over the years that blackbirds don't generally take food from bird feeders, unlike the bluetits and goldfinches who frequent our garden. Instead they scuttle around the earth below, picking up the crumbs dropped by those feeding overhead. In recent weeks I've often seen as many as six blackbirds, bickering over the leftovers and chasing each other around the flowerbed.
Since we replanted our birdfeeder tree into a more upright position and reorganised the feeders though, a few of these intelligent birds have used some lateral thinking. They realised they can stand on one of the branches to reach the fatball feeder, from where they can scoff much tastier and larger morsels of food. This particular branch is now frequented by a steady stream of blackbirds, all stuffing their beaks with high energy food, to keep them fuelled through the tough winter months.