Avian clutch size of increasing clutch size with increasing latitude. The proximate and ultimate causes for this pattern have been a subject of intense debate involving the ideas of group and individual selection. David Lack observed a direct relationship between latitude and avian clutch size. Birds near the equator laid approximately half as many eggs as those that resided in northern temperate habitats. He observed an increasing clutch-size from the equator towards the poles (something he referred to as the “latitude trend”) for many passerine (perching) birds, near-passerine (tree-dwelling) birds and in various other groups: Strigiformes, Falconiformes, Ciconiiformes, Laridae, Ralliformes, Galliformes, Podicipedifomes, and
Birds International exotic birds has existed for decades. In the Senate report titled "Commercial Utilisation of Australian Native Wildlife" an entire paragraph is set apart for Birds International experience based on a submission: "As an example of the potential for expansion, Ms Anderson noted that an avicultural enterprise in Manila, 'Birds International' which houses six thousand birds on a property, breeds to order large quantities of birds for overseas markets. They retain 15 per cent of stock bred each year for future breeding. Ms Anderson believes that 'similar establishments could be developed in Australia to house specifically Australian species of birds and