Prey availability is known to limit reproduction of some species of nesting birds, but identifying the primary prey types of a species with a flexible diet can be challenging. For the White Ibis Eudocimus albus, a tactile feeding, medium‐sized wading bird, nestling prey composition is suggested to depend on landscape water depths/availability of foraging habitat at the time of nesting and on historical drying events affecting prey production. We collected and compared inter‐ and intra‐annual diet variation of White Ibis chicks reared in the Everglades over two years that were independently identified as being relatively good (2006) and poor (2007) nesting seasons. We collected 127 nestling boluses and analysed the temporal variation in biomass of eight functional prey groups using multivariate techniques. The boluses from 2006 in the central Everglades were dominated by fish, but in 2007, after fish had been reduced by the previous year of drying, the boluses from the same region were more variable and dominated by garbage (i.e. scavenging). Analysis of five different collections taken from a different colony in the northern Everglades indicated that boluses were characterized by crayfish and had fewer fish or less garbage when landscape water depths were relatively higher and more preferred habitat was available. At lower landscape water depths in 2007 the bolus composition shifted away from crayfish towards small fish and urban food (terrestrial insects and garbage). Our results support the suggestion of depth‐dependent diets; prey composition depends on the current landscape water levels around the colonies, and also suggests that previous drying events can lead to increased reliance on alternative food sources. White Ibis partially compensated for unavailable aquatic prey with alternative urban foods, but their nesting success appears to have suffered.

We propose that effective community size can be defined on the basis of the web of indirect interactions experienced on average by each individual species. Indirect interaction chains are composed of links provided by direct interactions. We analyzed previously published data on 20 assemblages of species. Chain strengths were estimated by the weakest link and by the product of link strength. The average strength of the interaction chain decreased with increasing numbers of links with both models. Positive indirect interactions in chains with an even number of links offset negative direct interactions. We set the community size by the chain length where 95% of the indirect interactions are weaker than 10% of the mean of the absolute value of direct interaction strength. Using the multiplicative model, seven assemblages had a community size (web of interaction length) of three links, one of four links, and the remainder of communities were too small to set community size. The analysis suggests that communities of effective size are rarely investigated in ecological experiments.

The Menindee Lakes system in the Darling Riverine Plains bioregion in western New South Wales supports a diverse terrestrial vertebrate fauna. A survey of this fauna in spring 2000 and summer 2001 for the New South Wales Department of Land and Water Conservation revealed 12 mammal families (representing 25 species), 60 families of birds (164 species), eight reptile families (39 species), and two families of frogs (at least 7 species). Several new vertebrate species for the area were recorded, including the Stripe-faced Dunnart Sminthopsis macroura, Regent Parrot Polytelis anthopeplus and Woodland Blind Snake Ramphotyphlops proximus. Including historical records, the Menindee Lakes supports at least 305 terrestrial vertebrate species, including 18 species that are considered officially threatened in an international, national, or state context. At least another 18 terrestrial species are considered threatened regionally. Eight bird species are also protected under international agreements (JAMBA and CAMBA). The amount of woodlands in the region is relatively small, typically restricted to floodplains and the periphery of lakes, and usually dominated by either Black Box Eucalyptus largiflorens or River Red Gum E. camaldulensis. These woodlands, particularly the Black Box-dominated communities, were found to support relatively high numbers of terrestrial species because the Lower Darling River, its lakes and floodplains, provide resource-rich habitats in an otherwise resource-poor landscape.