RSPB Big Garden Birdwatch

This weekend just gone, was the annual RSPB Big Garden Birdwatch.  This is where the public are asked to watch their garden for an hour and record which birds visit.  A form is filled in online or you can send a form in.  All information is collated and there is a report later in the year, which gives a nationwide view of garden bird distribution.
Its a great thing to do because it gets loads of people interested.  However, I’m not too sure of the scientific credibility of it?  Anybody???
My count was done on Sunday and I didn’t get as many birds as I have done on other days.
Blue tit 2
Great tit 2
Bullfinch 2
House Sparrows 10
Dunnock 1
Blackbird 2
Brambling 1
Goldfinch 1
Robin 1
Greenfinch 2
Collared Dove
Long tailed tit 3
Coal tit 1
Actually, I suppose I did get most of the species I usually get, but not as many.  I didn’t get any Starlings which is unusual or any Wood Pigeon, or Magpies or Chaffinch.
Anybody else????