Blue tits and great tits are now regular visitors to our bird feeder. While there are similarities in colour, the blue tit is the smaller of the two birds. Both birds have white cheeks but the blue tit has a blue cap and a black stripe that passes through the eye.
The larger great tit has a black cap and a distinctive black stripe down the breast. Both birds will often tolerate each other at the bird feeder but great tits are frequently more aggressive and chase of other smaller birds.
Check out the bird feeder webcam for live steaming of birds visiting the feeder.
https://www.railwaylandlive.org/live/bird-feeder/