Budgerigar-Fancier’s Lung is a form of extrinsic allergic alveolitis, resulting from sensitization to budgerigars, or parakeets as they are known in North America. Skin tests have revealed sensitization to the birds’ droppings and/or serum. As it is estimated that budgerigars are kept in 5-6 million homes in Britain, current figures suggest that anything up to 900 per 100,000 of the population are exposed to the risk of developing this condition.