Song Thrush (Turdus philomelos)

Song Thrushes or Throllies as we called them when I was a lad are not doing well they have been declining in numbers for a while.  Over the last year we have been getting one visiting the garden.   A result of lockdown?   I have no idea.

Today I thought I had made a scientific breakthrough, I know why they are declining.  Blackbirds!   Sorry I am only joking but I did see behaviour I have never seen before.  The Thrush was wandering across the grass and bothering nobody.   A male Blackbird spotted it flew down and chased it under the Holly.   Then followed.   The Thrush popped out the otherside  pursued by the Blackbird.   This went on for some minutes until the Thrush gave up and flew away.   Why?   Again I have no idea, it isn't as if they are the same species competing for either mates or nest sites/territory.