In the gathering gloom under a light drizzle one late December afternoon, a flock of seven mistle thrushes fly from tree to tree, all uttering their staccato contact calls which remind me of someone whirling an old-fashioned wooden football rattle.

The birds seem agitated and don't settle for long so this could be a demonstration of early season courtship behaviour. Suddenly a male begins to sing, if his offering can be called a 'song' as it is nowhere near so melodious as that of his cousin, the song thrush.

Nature Notes: Where will all the birds go?

Mistle thrushes are the birds mainly responsible for spreading mistletoe by eating the indigestible seeds of the berries which then emerge in the bird's droppings, stick to branches and create new plants.

Then on the morning of December 12, I went into the garden to hear a loud 'kronk-kronk' call above and was amazed to see a raven flying north east towards Wimbledon common. All the local crows had spotted the raven and got in quite a flap, flying around cawing, loudly protesting about their much larger relative above. Ravens are mainly residents of mountains and wooded cliffs in the west of England and ravens in the tower of London have their wings clipped so can't fly far.

Nature Notes: Winter birds of prey

Perhaps the bird had escaped from a private collection? But what was the raven doing over south west London? The answer remains a mystery.