Breeding

Blue tits breed wherever there are areas of trees with suitable nest holes. They start looking for nesting sites about February, preferring small holes or narrow cracks in trees about 1 - 15 metres from the ground. Nest-boxes in gardens are readily used, especially if there is a shortage of natural sites in an area. Both males and females search for nest holes, but when the male finds somewhere suitable, he displays by fluttering his wings and calling to his mate; he will then go into the hole, calling the female and hoping she will follow and approve the site. She doesn't always approve it and may reject several before deciding on the one she wants! She builds the nest alone, collecting moss, dried grass, dead leaves and wool to fill the bottom of the nest hole; she forms a cup-shaped structure with this material and finally lines it with soft feathers or hair.

A clutch of 7 - 13 eggs is laid from mid-April to early May. The eggs are white with reddish-brown speckling and are laid at the rate of one a day. Incubation begins only when the clutch is almost complete - the female usually covers the eggs with some nest lining if she has to leave them for a while.

Incubation lasts almost two weeks and whilst the female is sitting on the eggs, the male defends the area around the nest site from other blue tits, so protecting the available food needed for both adults and, later, the young. He also brings food to his mate. The young hatch at a time when food is at its most abundant. They are fed by both parents, mainly on small caterpillars, and stay in the nest for two or three weeks. The adults also remove the droppings regularly, to keep the nest clean.