Where's the birds

Usually lots of birds in my garden.

Especially Gold finches ( often 5+ at any time ), blue tits and robin, yet the Garden Birdwatch arrives and only saw a couple of species and not one gold finch, they are back in number today.

I note many other having similar problem with usual busy garden becoming deserted typicaly for just the one day

It was the first day of the thaw here and the melted snow revealed lot of grass, shrubs etc that had been covered for 10 days could this have revealed alternative food sources that presented a good alternative to my offering?