Research in the 1960's by CSIRO Division of Wildlife Research proved that there were five species of crows and ravens in Australia instead of three as previously thought. To those people who are not good at remembering bird calls, separating these five all black, all white-eyed birds is difficult and at times impossible. Knowing where each species should occur is the first step, but remembering their calls is undoubtedly the most useful aid.(Listen to all five species on their respective sound pages) Changes in land use are affecting corvid distribution and in the case of Little Ravens, the expansion of inland irrigation means that they now occur as far north-west as Bourke in NSW and further up the Darling R. system, over the border into Queensland near Dirranbandi. There are a few places where Little Ravens normally occur alone, like high country where there is winter snow, all along the Great Dividing Ra. as far north as Barrington Tops. Near Sydney, at Oberon, Goulburn, Moss Vale and Bowral they are the resident corvids. In metropolitan Melbourne and Adelaide also, Little Ravens predominate. Out on the Hay Plain in NSW they are very common and in some areas with few trees, they sometimes nest quite close to the ground. Over most of their range, the Australian Raven also occurs but these two are quite easy to tell on voice alone. Little Crows sound a bit like Little Ravens. The distribution of these two species now overlaps along a broad zone from Brewarrina in NSW to Penong in S.A. At Cobar rubbish tip, Australian Ravens, Little Ravens and Little Crows all occur together and there is no better place to compare calls than where all three species occur at once. In coastal eastern Victoria and at the Coorong in S.A. both Forest Ravens and Little Ravens sometimes occur together and in such a situation, precise identification can be very difficult.