The Yellow-billed Spoonbill Platalea flavipes is very similar in appearance to its close relative, the royal spoonbill. It differs in a number of aspects. The royal spoonbill nearly always has immaculate white feathers, while the yellow-billed spoonbill often has a rather dirty appearance. Where the royal spoonbill is black (bill and legs) the yellow-billed is, of course, yellow, but instead of having a black face, the yellow-bill has a white to pale grey face and its head feathers wrap around the eyes a little. In adult birds the face is separated from the white head feathers by a thin black line. Young birds, the majority of individuals seen so far in the Goulburn Wetlands, have no such line.
When yellow-billed spoonbills are in breeding plumage the black lines are more distinct and dark streaks (lacy feathers) appear on the back between the wings. In addition, the feathers on the breast become longer and project out, as can be seen in the photo at the top of this page.
All spoonbills — unlike herons but like ibis — fly with their necks stretched out (the herons and egrets tuck them in).
Unlike royal spoonbills, yellow-billed spoonbills are pretty anti-social. While they get along peacefully with other species, they tend to prefer their own company and are usually found alone. This has mostly been the case in the Goulburn Wetlands except for the few weeks when food was in superabundance as the water dried out. Then there were two to four yellow-billed spoonbills at a time, feeding separately, whereas the royal spoonbills that were often grouped together, sweeping the waters cooperatively.
While royal spoonbills sweep the waters rapidly, mainly looking for fish, yellow-billed spoonbills tend to take their time and eat less fish and more small water insects.
Interestingly perhaps, recent DNA analysis has shown that yellow-billed spoonbills are out on a separate branch from the other spoonbills and that their closest relative, also on this branch, is the bright pink Roseate Spoonbill from the southern USA, Central and South America. How this happened is a mystery worth solving.
The royal spoonbills need waterless than 40 centimetres deep in which to feed, as does the yellow-bill, but yellow-billed spoonbills are also able to utilise tall grassland. Unlike the royals, they can survive where all the fish have been removed. Perhaps it is because the yellow-billed spoonbills have a greater environmental tolerance that they tend to outnumber royals, at least in the inland. As for the Goulburn Wetlands, after the frosts had shrivelled what was left of the water ribbons into yellowish mush, the drought had reduced the water to a few shallow puddles and the massed flocks of waterbirds had removed the vast majority of food and turned the mud into a quagmire with plentiful holes pierced by hundreds of ibis beaks, there remained a solitary yellow-billed spoonbill, clearly still able for a few weeks at least to feed itself on what little was left.