On ev'ry tick there is a tick upon his back to bite 'em
And on that tick a littler tick
and so Ad Infinitumů.
With acknowledgements to Jonathan Swift and Augustus de Morgan
This is the third double tick I have had off my little springers this year! Two of them during a week walking on Arran at the beginning of June and these yesterday. I wonder if they were already a pair when she picked them up or they found her independently and joined up after?