 The nest is 12 – 15 cm ( 4 @.@ 7 – 5 @.@ 9 in ) in diameter and 3 – 4 cm ( 1 @.@ 2 – 1 @.@ 6 in ) deep . The clutch is 6 – 14 , usually 8 – 12 eggs ; these are oval , slightly glossy , creamy or <unk> with green , blue or grey , and blotched red @-@ brown . They average 37 mm × 26 mm ( 1 @.@ 5 in × 1 @.@ 0 in ) and weigh about 13 – 16 g ( 0 @.@ 46 – 0 @.@ 56 oz ) , of which 7 % is shell . The eggs are laid at daily intervals , but second clutches may sometimes have two eggs added per day . Incubation is by the female only ; her tendency to sit tight when disturbed , or wait until the last moment to flee , leads to many deaths during hay @-@ cutting and harvesting . The eggs hatch together after 19 – 20 days , and the precocial chicks leave the nest within a day or two . They are fed by the female for three or four days , but can find their own food thereafter . The juveniles fledge after 34 – 38 days . The second brood is started about 42 days after the first , and the incubation period is slightly shorter at 16 – 18 days . The grown young may stay with the female until departure for Africa . 
