Autumn is a season of subtle charms. Summer woos us all with its cascading colours and bright blue skies, and spring s rush of new life is inspiring. It takes time to get to love autumn, particularly as it marks the end of the long, hot days of summer. I

Autumn is a season of subtle charms. Summer woos us all with its cascading colours and bright blue skies, and spring's rush of new life is inspiring. It takes time to get to love autumn, particularly as it marks the end of the long, hot days of summer.

I am growing used to the mournful song of robins as a prelude to every day as I leave my house. It adds a pleasant backdrop to any venture outside at the moment. The song of this much-loved bird lacks the variety and excitement it has in spring during autumn and winter and is slower and less varied musically.

Having completed their late-summer moult to replace tatty feathers that failed to stand up to the extreme test of raising a family, they are now ready to set up their non-breeding territories.

Both male and female robins defend their own territories outside the breeding season. You'll see regular skirmishes now as the birds cement the boundaries. There are always those that stray into another's territory, and this is not wise. Robins are fiercely territorial. They look so placid and friendly, but this is misleading. There are few other birds in the garden that can be as aggressive as the robin. Fights to the death happen occasionally, but these are usually during the breeding season.

For me, the robin is very much a bird of autumn (despite its association with Christmas). Its dominating birdsong and these territorial disputes make it a very obvious part of this season.

In addition, visits to the coast coinciding with periods of east winds can bring encounters with hundreds, sometimes thousands, of Scandinavian robins that come here for winter. It is an amazing experience to be walking through the dunes with a robin popping out of every bush. It is an almost unreal situation.

I've been lucky enough to experience a few spectacular 'falls' of Scandinavian migrants and one particular 'day of robins' about 10 years ago up on the Norfolk coast really sticks in my mind. If only there were always so many birds around.

These birds soon filter inland and increase the nation's robin population. Arrivals start about now and continue right through October, so keep an eye out for any sudden increases in robins in areas you watch regularly. You may have been invaded.