After their astonishing flights back from Africa house martins have been feeding up to get their strength up and this month they start nesting. The nests can take up to a fortnight to build and created from mud, grass, feathers and vegetal matter. They are grouped together in small colonies. Both parents sit on the four or five white eggs in each nest and it takes just two weeks for them to hatch. The chicks are without feathers for the first week so the female broods them to keep their temperatures up but both parents feed them. After around three weeks thee chicks are ready to fledge.