How the goldfinch brings life to the bird in 'the laburnum top'

In the morning Goldfinch used to go to find food to feed her children's. In this poem goldfinch has referred  as engine of her family and children has referred as machine.Goldfinch used to go to find food and feed her children's. Food is like fuel in this poem for children's. similarly,feeding birds by goldfinch brings life to the birds.