CHENGDU?-?Construction on a subway line in Chengdu city in southwest China was put on hold as workers waited for a nest of vinous-throated parrotbills to mature.

The five young birds flew the nest recently, allowing work to resume on the city's new line seven on Wednesday afternoon.

Children from the Golden Apple Emiile Kindergarten spotted a nest containing the bird's blue eggs on April 9 near their school's back door.

On April 18, just four days after the eggs had hatched, the construction team informed the kindergarten that its back door needed to be relocated to make way for the subway.

Fearing that noisy building work would scare away the nestlings' parents, children and staff of the kindergarten sent a letter and drawings to the construction team, requesting that work be postponed until the birds were strong enough to fly away, according to Mao Weilin from the kindergarten.

China Railway Engineering Corp.'s Chengdu branch agreed.

"I hope the little birds will return one day with their children," one student, nicknamed Abu, told his mother.