 The Australian pelican has two reproductive strategies depending on the local degree of environmental predictability . Colonies of tens or hundreds , rarely thousands , of birds breed regularly on small coastal and subcoastal islands where food is seasonally or permanently available . In arid inland Australia , especially in the endorheic Lake Eyre basin , pelicans will breed opportunistically in very large numbers of up to 50 @,@ 000 pairs , when irregular major floods , which may be many years apart , fill ephemeral salt lakes and provide large amounts of food for several months before drying out again . 
