The Egyptian plover, also known as the crocodile bird, is a wader, the only member of the genus Pluvianus. Formerly placed in the pratincole and courser family, Glareolidae, it is now regarded as the sole member of its own monotypic family Pluvianidae. The species is one of several plovers doubtfully associated with the "trochilus" bird mentioned in a supposed cleaning symbiosis with the Nile crocodile.
Description
The Egyptian plover is a striking and unmistakable species. The 19–21 cm long adult has a black crown, back, eye-mask and breast band. The rest of the head is white. The remaining upperpart plumage is blue-grey, and the underparts are orange. The longish legs are blue-grey. In flight, it is even more spectacular, with the black crown and back contrasting with the grey of the upperparts and wings. The flight feathers are brilliant white crossed by a black bar. From below, the flying bird is entirely white, apart from the orange belly and black wing bar. After landing, members of a pair greet each other by raising their wings in an elaborate ceremony that shows off the black and white markings. The sexes are similar, but juveniles are duller and the black marking are intermixed with brown.
Habitat and range
The Egyptian plover is a localised resident in tropical sub-Saharan Africa. It breeds on sandbars in very large rivers.
Behaviour
This usually very tame bird is found in pairs or small groups near water. It feeds by pecking for insects. The call is a high-pitched krrr-krrr-krrr.
Breeding
Its two or three eggs are not incubated, but are buried in warm sand, temperature control being achieved by the adult sitting on the eggs with a water-soaked belly to cool them. If the adult leaves the nest, it smooths sand over the eggs, though if it is frightened the job may be hasty. The chicks are precocial, and can run as soon as they are hatched and feed themselves shortly afterwards. The adults cool the chicks in the same way as with the eggs. The chicks may drink water from the adult's belly feathers. The adults bury the chicks in the sand temporarily if danger threatens.
Supposed relationship with crocodiles
The bird is sometimes referred to as the crocodile bird for its alleged symbiotic relationship with crocodiles. According to Herodotus, the crocodiles lie on the shore with their mouths open and a bird called "trochilus" flies into the crocodiles' mouths so as to feed on decaying meat lodged between the crocodiles' teeth. The identification of the trochilus with any particular plover is doubtful, as is the cleaning symbiosis itself; no known photographic evidence exists, and the written accounts are considered suspect by the biologist Thomas Howell.
