The family Threskiornithidae includes 34 species of large wading birds. The family has been traditionally classified into two subfamilies, the ibises and the spoonbills. Members of the family have long, broad wings with 11 primary feathers and about 20 secondaries. They are strong fliers and, rather surprisingly, given their size and weight, very capable soarers. The body tends to be elongated, the neck more so, with rather long legs. The bill is also long, decurved in the case of the ibises, straight and distinctively flattened in the spoonbills. Ibises all have long, downcurved bills, and usually feed as a group, probing mud for food items, usually crustaceans. They are monogamous and highly territorial while nesting and feeding. Spoonbills are most easily distinguished from ibises in the shape of their bill, which is long and flat and wider at the end. The nostrils are located near the base of the bill so that the bird can breathe while the bill is submerged in water.