A widespread and common species throughout the country and their calls accompany one on any walk through the countryside, though they are also in urban environments. Great Tits have a wide variety of calls and it is often said that if one hears a creaking gate anywhere in the woods - well, it's a Great Tit.
Males and females, though superficially similar, are told apart by the black longitudinal line down their chest and belly. The male's is wide, unbroken and spreads as it approaches the vent, whereas the female's tapers to a diffuse break low on the belly.
Like the Blue Tit, they are thinner on the ground in southern Portugal than further north.
Joomla Gallery makes it better. Balbooa.com