Where are all the birds?

There has been a strange absence of birds in the garden recently and still today. Not one blackbird, robin, finch, sparrow or tit has visited but besides that, we have heard no bird calls.
We would normally have lots of birds visiting as we feed them all year round and have 2 bird baths we keep topped up for them.
The hedgehogs are still coming but the birds seem to have vanished.