Amazing footage shows two birds building a nest from scratch in just 15 days.<br /><br />Marta, 34, who wishes to keep her surname private, first spotted two western house martins setting up shop on the wall outside her office window on May 14.<br /><br />Marta documented the building process as the birds used dirt and their own saliva to construct the home.<br /><br />The birds will continue to live in the nest, as long as it goes undisturbed, until the season is over in autumn.
