WS #7: Acrobatic Multi-Vocalist
The cache, a camo-taped plastic pot, is hidden near the river and a large sycamore in which this common, widespread and distinctive bird was calling strongly.
To reach the cache location: (from the west) park @ or near N 53 54.957 W 1 44.698 on the approach road to the old mill complex and after securing your car, cross the road and pick up the small trail heading across the top of the woodland, down to and along the river.
(from the east) park @ or near N 53 54.578 W 1 43.635 in the lay-by and pass through the gate at its west end into the field and cross the short distance to the cache location by the river.
The great tit (Parus major) is a passerine bird in the tit family Paridae. It is a the most widespread species in the genus Parusand common throughout Europe, the Middle East, Central and Northern Asia, and parts of North Africa where it is generally resident in any sort of woodland. Most great tits do not migrate except in extremely harsh winters. There are some 15 subspecies of which P.m. newtoni is the one found in Britain.
It occupies a range of habitats and is most commonly found in open deciduous woodland, mixed forests, forest edges and gardens, where it is a popular visitor to bird-feeders - being particularly fond of sunflowers seeds and then, as a 2nd choice, peanuts.
It is a distinctive bird with a black head and neck, prominent white cheeks, olive upperparts and yellow underparts, with some variation amongst the numerous subspecies. It is predominantly insectivorous in the summer, but will consume a wider range of food items in the winter months - including small hibernating bats!
Like all tits it is a cavity nester, usually nesting in a hole in a tree. The female lays around 12 eggs and 
incubates them alone, although both parents raise the chicks. In most years the pair will raise two broods. The nests may be raided by woodpeckers, squirrels and weasels and infested with fleas, and adults may be hunted by sparrowhawks.
Like other tits, it is a vocal bird, and has up to 40 types of calls and songs! The calls are generally the samebetween the sexes, but the male is much more vocal and the female rarely calls. Soft single notes such as 'pit', 'spick', or 'chit' are used as contact calls. A loud 'tink' is used by adult males as an alarm or in territorial disputes. One of the most familiar is a 'teacher, teacher', often likened to a squeaky wheelbarrow wheel, which is used in proclaiming ownership of a territory. In former times, English folk considered the 'saw-sharpening' call to be a foretelling of rain. Listen to calls here, here, here and here.
One explanation for the great tit's wide repertoire is the Beau Geste hypothesis. The eponymous heroes of the famous novel propped dead soldiers against the battlements to give the impression that their fort was better defended than was really the case. Similarly, the multiplicity of calls gives the impression that the tit's territory is more densely occupied than it actually is. Whether the theory is correct or not, those birds with large vocabularies are socially dominant and breed more successfully.
It is a popular garden bird due to its acrobatic performances when feeding on nuts or seed. Its willingness to move into nest boxes has made it a valuable study subject in ornithology; it has been particularly useful as a model for the study of the evolution of various life-history traits, particularly clutch size. Other research suggests that British great tits are evolving longer beaks as an advantage in accessing food at bird feeders/
It is more common and has better breeding success in areas with undisturbed forest cover, but it has adapted to human modified habitats and can be very common in urban areas - the breeding population in Sheffield (pop. 500,000) has been estimated at some 17,000 birds. In adapting to human environments its song has been observed to change in noise-polluted urban environments. In areas with low frequency background noise pollution, the song has a higher frequency than in quieter areas.
See here for more information on this great little bird.