Starlings, sparrows and even doves are set to swoop in and be counted by families as they help assess the health of our countryside.
Half a million people - many from the comfort of their own home - counted seven million birds last year but the Royal Society for the Protection of Birds wants to smash those figures this weekend.
Surveys help keep track of our birds and gives a great indicator of the health of the countryside so twitchers will be counting the likes of wrens, tits and robins for the 37th Big Garden Bird Watch.
Blackcaps and siskins should also sweep in to birdtables and feeders along with dunnocks and blackbirds - which feed on the ground.
Watchers commonly use seed cakes and bug mixes to tempt in the colourful varieties and provide clean, shiny water for them to bathe in.
Families are challenged to make a day of it by building jazzy bird feeders from plastic bottles or make jelly worms to snack on while they watch.
Last year, the house sparrow was the most spotted bird but figures show numbers are down by 62 per cent since the fist birdwatch in 1979.
Many birds have been badly hit by changes in woodland management, the decline of wild flowers and the use of pesticides but a definitive answer is hard to establish.
John Gearing, chairman of Bucks Bird Club, said the plummeting figures are a worry but the drop in sightings throughout Bucks is ‘not as severe’ as it has been nationally.
He said: “There isn’t a clear answer to why the numbers are going down but what would the county be like without birds?
“The way bird life has changed is quite dramatic. If you said to someone 20 years ago that there was a red kite in their garden, they would have been startled.
“I think we will find that the tops of the charts will be tits and especially the long-tailed tits.
“They have had two very good breeding seasons - after a poor season previously, they then got their breeding in early. And robins have had quite a good year.
“A few species have crept in too like the great white egret. People would never have dreamt of having that in their garden.
“And at this time of year, there are a lot of immigrant species like the winter thrushes from Scandinavia or Siberia. People think golly gosh, they’ve come all the way from there.”
The starling, ranked third last year, is red-listed like the house sparrow as numbers have plummeted by 84 per cent while the great spotted woodpecker made the top 20 for the first time ever.
Some of the rarer varieties included the barn owl which was spotted 107 times and the waxwing which visited 30 gardens.
But with just one sighting, the yellow-rumped warbler was the rarest bird to be spotted in the UK last year - registered by Emily Power, 12, and her nine-year-old brother, Thomas.
Simply register online and then spend just one hour over this weekend counting the birds in your garden or nearby green space.
Watchers can even download a live bird counter to save the trees and make it even simpler.
There is also an indoor meeting in Aylesbury with guest speaker Chris Ward talking people through his Wild Britain diary.
It takes place on Monday at the Prebendal Hall Community Centre in Fowler Road and starts from 7.30pm.
Find out more about the Bucks Bird Club at www.bucksbirdclub.co.uk and for more information about the Big Garden Bird Watch, visit www.rspb.org.uk