Judging by the size, feathers and leg colour almost certainly Quail. They are described as 'challenging and exciting' to shoot as they are small and nibble.
Most are farmed. Wild ones are migratory and the RSPB has them on their amber warning list.
There were 540 breeding males recorded in the UK, that might now be 539. Kinda sums up many of my attitudes to 'the sport' of shooting. There's about as much meat in a chicken nugget, which when I last checked isn't on the endangered list, but is not as much 'fun' to shoot.