The grey-necked rockfowl (Picathartes oreas) is a medium-sized bird in the family Picathartidae with a long neck and tail. Also known as the grey-necked picathartes, this passerine is mainly found in rocky areas of close-canopied rainforest from south-west Nigeria through Cameroon, Equatorial Guinea, and south-west Gabon. It additionally lives on the island of Bioko. Its distribution is patchy, with populations often isolated from each other. The rockfowl typically chooses to live near streams and inselbergs in its forested habitat. It has no recognized subspecies, though some believe that it forms a superspecies with the white-necked rockfowl. The grey-necked rockfowl has grey upperparts, a light grey breast, and lemon-coloured underparts. Its unusually long tail is used for balance, and its thighs are muscular. The head is nearly featherless, with the exposed skin being powder blue on the forehead and upper mandible and carmine on the hindcrown. The bird's cheeks and eyes are covered in a large, circular black patch that, though narrow, connects and divides the carmine and powder blue skin at the peak of the crown. Though the bird is usually silent, some calls are known.

This rockfowl feeds primarily on insects, though some plant matter, such as fruit and flower buds, is eaten. One feeding strategy involves following Dorylus army ant swarms, feeding on insects flushed by the ants. Rockfowl move through the forest mainly through a series of hops and bounds, or short flights in low vegetation. It travels either alone or in small groups. This species rarely flies for long distances. The grey-necked rockfowl is monogamous and pairs nest either alone or in the vicinity of other pairs, sometimes in colonies of two to five nests, though one colony of forty nests has been recorded. These nests are constructed out of mud and are formed into a deep cup that is built on rock surfaces, typically in caves or on cliffs. Two eggs are laid twice a year. Though the birds breed in colonies, infanticide exists in this species, with rockfowl attempting to kill the young of other pairs. Nestlings mature in about a month.

This species is classified as vulnerable as its dwindling and fragmented populations are threatened by habitat destruction. A conservation plan has been drawn up for this species, and research into its current distribution is ongoing. Some of the indigenous peoples of Cameroon either respect this species or, in some cases, fear it. Today, this rockfowl is considered one of Africa's most desirable birds by birders and is a symbol of ecotourism across its range.

This rockfowl measures approximately 33 to 38 centimetres (13 to 15 in) in length, with its notably long tail contributing about 14 centimetres (5.5 in). This species does not show sexual dimorphism. The adult's head is largely featherless, and the skin on the forehead and forecrown as well as the upper mandible of the beak behind the bird's nostril is a powder blue. The lower mandible and rest of the upper mandible are black. This beak is unusually large and crow-like at 30 millimetres (1.2 in) in length and is also decurved. There are some small, bristle-like feathers located on the crown that can be erected. Behind the crown, the species' bare skin on the hindcrown and nape is carmine in coloration and has a few more bristle-like feathers. The area between these patches of skin, as well as the lores, cheeks, and ear region, are featherless with black skin. Its eyes are dark brown. The grey-necked rockfowl's mantle, back, rump, and uppertail coverts are all grey. The feathers on the rump are long, dense, and silky. Additionally, the tail is grey. The rockfowl's chin, throat, sides of the neck, and upper breast are all a pale grey. This bird is buffy lemon in colour on its lower breast, belly, flanks, thighs, and undertail coverts, though the flanks can sometimes appear to be greyish. The wing is grey, though the wing's remiges are black, forming a line between the lemon underparts and grey upperparts. Its legs and feet are silver-grey and muscular. The adult rockfowl weighs 200 to 250 grams (7.1 to 8.8 oz).

The nestling is born nearly featherless except for tiny primary quills and a fine down along its spine, humerus, forearm, and femur. Its skin is dark pink but displays variable black patches on its upperside. The gape is yellow. As the nestling develops, its plumage begins to resemble that of the adult, though it has white flecks on its wing coverts and the featherless skin on the head is black or dark brown, not powder blue, on the forecrown and dark reddish brown, not carmine, on the hindcrown. After fledging, the immature closely resembles the adult except for the bare patch on the back of the head being golden yellow instead of carmine and the tail being only a third as long as that of an adult.

The grey-necked rockfowl is a relatively silent species. It has been known to give a quiet, one to two second long, hissing "wheet" call several times at intervals of about four seconds. To give this call, the rockfowl opens its beak and inflates its throat. When bringing food to their nests, the adults give one or two "peep"s. After reaching the nest, the adult repeatedly makes a low "ga-a-a" sound that has been described as being between a snore and a sigh. It also makes a hissing noise that has been described as a "shisss".