 Incubation lasts thirteen days , although the last egg laid may take 24 hours longer than the first to hatch . Both parents share the responsibility of brooding the eggs , but the female spends more time incubating them than does the male , and is the only parent to do so at night when the male returns to the communal roost . The young are born blind and naked . They develop light fluffy down within seven days of hatching and can see within nine days . Once the chicks are able to regulate their body temperature , about six days after hatching , the adults largely cease removing droppings from the nest . Prior to that , the fouling would wet both the chicks ' plumage and the nest material , thereby reducing their effectiveness as insulation and increasing the risk of chilling the hatchlings . Nestlings remain in the nest for three weeks , where they are fed continuously by both parents . Fledglings continue to be fed by their parents for another one or two weeks . A pair can raise up to three broods per year , frequently reusing and relining the same nest , although two broods is typical , or just one north of 48oN . Within two months , most juveniles will have moulted and gained their first basic plumage . They acquire their adult plumage the following year . As with other passerines , the nest is kept clean and the chicks ' faecal sacs are removed by the adults . 
 Incubation <a href='uninflect' title='1'><mark>lasts</mark></a> thirteen days , although the last egg laid may take 24 hours longer than the first to hatch . Both parents share the responsibility of brooding the eggs , but the female <a href='uninflect' title='2'><mark>spends</mark></a> more time incubating them than <a href='uninflect' title='3'><mark>does</mark></a> the male , and <a href='drop_aux' title='4'><mark>is</mark></a>the only parent to do so at night when the male returns to the communal roost . The young are born blind and naked . They develop light fluffy down within seven days of hatching and can see within nine days . Once the chicks <a href='drop_aux' title='5'><mark>are</mark></a>able to regulate their body temperature , about six days after hatching , the adults largely cease removing droppings from the nest . Prior to that , the fouling would wet both the chicks <a href='null_genetive' title='6'><mark>'</mark></a>plumage and the nest material , thereby reducing their effectiveness as insulation and increasing the risk of chilling the hatchlings . Nestlings remain in the nest for three weeks , where they are fed continuously by both parents . Fledglings continue to be fed by their parents for another one or two weeks . A pair can raise up to three broods per year , frequently reusing and relining the same nest , although two broods <a href='drop_aux' title='7'><mark>is</mark></a>typical , or just one north of 48oN . Within two months , most juveniles will <a href='been_done' title='8'><mark>have</mark></a> moulted and gained their first basic plumage . They acquire their adult plumage the following year . As with other passerines , the nest is kept clean and the chicks <a href='null_genetive' title='9'><mark>'</mark></a>faecal sacs are removed by the adults . 
Incubation last thirteen dayz , although da last egg laid may take 24 hours longer den tdafirst to hatch . Both parents share the responsibility of brooding the eggs , but thdaemale spend more time incubating them than do the male , and thedaly parent to do so at night when the male returns to the communal roost . The dang r born blind and naked . They develop light fluffy down within seven days of hatching and can see within nine days . Once the cdaks able to regulate their body temperature , bou six dayz after hatching , the addas largely cease removing droppings from the nest . Prior to dat , the fouling would wet both the chicks  plumage and the nesdaaterial , thereby reducing their effectiveness as insulation and increasing the riskda chilling the hatchlings . Nestlings remain in the nest for three weeks , where they arred continuously by both parents . Fledglings continue to be fed by their parents fir another one or 2 weeks . A pair can raise up to three broods per year , frequently reusing and relining the same nest , although tw2roods typical , or just one north of 48oN . Within two months , most juveniles gon done moulted and gained their first basic plumage . They acquire their adult plumage the follodag year . As with other passerines , the nest is kept clean and the chicks  faecal sacs are removed by the adults .