In article , david@abacus-
nurseries.co.uk says...

I don't know what has happened, from having a mass of birds on the
feeders suddenly yesterday there were almost none, I saw less birds on
them yesterday than I had been seeing in 15 mins. today is the same,
it's almost as if they have all migrated, but Tits etc. just don't do that.
Anyone else had the same?
David @ a sunny side of Swansea Bay

Strange, I posted a follow up yesterday morning, but it seems
to have disappeared into the ether!

There are a number of possible causes:

Sparrowhawk, as mentioned elsewhere
Cat sitting under the bushes
Stale food
Someone nearby has put out different/nicer feed (my experience
here)

There is also a time element. Our sparrows are alway here
around 8.30-9.00am and later on in the afternoon(counted 25ish
around the feeders, don't know how many in the ivy and bushes
nearby!). Tits and finches tend to come in 2-3's on and off all
day. Others just occasionally, nuthatches always single,
woodpeckers usually 1 or 2, although when the young were here,
there were two families around and upto 5 birds in the garden
together - although only 1 fed at a time, usually the male
first, then female, the babes in age order.

--
Roger T

700 ft up in Mid-Wales