Last year, almost 400,000 people joined in the popular survey that provides a vital snapshot of the UK's winter garden bird population.
The annual count, which has been going since 1979, helps the RSPB monitor which bird species' populations are increasing or decreasing. Sarah Kelly, Big Garden Birdwatch co-ordinator, said: "We had no idea the survey would prove so popular, but it just goes from strength to strength each year.
"It's really important for us as it helps identify which bird species are in decline and which are flourishing, so we can better use our resources to help them."
Taking part couldn't be easier. All you have to do is spend an hour watching and recording the maximum number of different bird species visiting your garden or local park at any one time.
The RSPB has put together a guide to help you identify some of the UK's most popular garden birds and the Mercury has reproduced the pictures and descriptions on these pages.
The best time to complete your survey is early morning as that's when birds are most active. It's also a good idea to put out a selection of foods, such as peanuts, seeds, fats and kitchen scraps, as you'll attract a greater variety of birds.
Download a survey form from www.rspb.org.uk/birdwatch and then record your findings on the website.


House sparrow
The noisy house sparrow is one of our most frequent garden visitors and is affectionately recognised as being a cheeky rogue with a promiscuous nature. Males have a grey crown, black bib, reddish-brown back and grey breast and belly, while females have brown, streaky backs and are buff below.

Starling
The starling is famed for its ability to mimic the calls of other birds and the mechanical noises in its varied repertoire of song. Smaller than blackbirds, with a short tail, pointed head and triangular wings, a starling looks black at a distance but when seen closer it is very glossy with a sheen of purples and greens.

Blackbird
The males live up to their name but, confusingly, females are brown often with spots and streaks on their breasts. The bright orange-yellow beak and eye-ring make adult male blackbirds one of the most striking garden birds. The blackbird has a long tail and often hops along the ground with its tail up.

Blue tit
Its colourful mix of blue, yellow, white and green make the agile blue tit one of the most attractive resident garden birds. Almost any garden with a peanut feeder will attract it. In winter it forms flocks with great tits, long-tailed tits and other woodland species as they search for food.
Chaffinch
The chaffinch is the UK's second commonest breeding bird, and is arguably the most colourful of the UK's finches. Its patterned plumage helps it to blend in when feeding on the ground and it becomes most obvious when it flies, revealing a flash of white on the wings and white outer tail feathers.

Woodpigeon
The UK's largest pigeon, pictured at the top right of the page, it is largely grey with a white neck patch and white wing patches, clearly visible in flight.

Collared dove
Distinctive with its buffy-pink plumage, black neck collar and long, white tail with a black base, the collared dove is usually seen singly or in pairs. After rapidly spreading across Europe in the early 20th century, the collared dove is now one of our most common birds, and its monotonous cooing is a familiar sound.

Robin
With its bright, orange-red breast, brown back and dumpy shape, the robin is a familiar garden bird and was officially adopted as Britain's National Bird in 1960. The robin sings nearly all year round and despite its cute appearance, it is aggressively territorial and is quick to drive away intruders.

Great tit
Bigger than the blue tit, the great tit is green and yellow with a striking glossy black head, white cheeks and a distinctive two-syllable song. The woodland bird has adapted to man-made habitats. It can be quite aggressive at a birdtable, fighting off smaller tits.
Goldfinch
A small, dainty, highly coloured finch with a bright red face and yellow wing patch. Goldfinches often feed in small flocks, and its twittering call and black and yellow wings draw attention to it.
They sometimes decorate the outside of their nests with aromatic flowers.

Greenfinch
Its twittering and wheezing song and flashes of yellow and green as it flies make this finch a truly colourful character. Although quite sociable, it may squabble among other greenfinches or with other birds at the bird table.
Has a forked tail and stout beak.

Dunnock
A small, easily overlooked bird, the dunnock creeps around under bushes in a mouse-like way.
It is a brown and grey bird with a slender beak, which it uses to catch its insect and spider food.
The dunnock is sedentary, rarely moving more than one kilometre from its birthplace.

Magpie
With its noisy chattering, black-and-white plumage and long tail, there is nothing else quite like the magpie in the UK.
When seen close-up its black plumage takes on an altogether more colourful hue with a purplish-blue iridescent sheen to the wing feathers, and a green gloss to the tail.

Long-tailed tit
The long-tailed tit is easily recognisable with its distinctive black, white and pink colouring, a tail that is bigger than its body, and undulating flight. Gregarious and noisy residents, long-tailed tits are most usually noticed in small, excitable flocks of about 20 birds.