#bucerotiformes

The Green Wood Hoopoe (Phoeniculus purpureus) (image 2) is a cooperative breeder, living in flocks of up to a dozen birds led by one breeding pair. After the chicks hatch, the mother and nestlings are fed by the rest of the group, even after they have fledged and left the nest hole. The whole group will fearlessly defend the nestlings against intruders.

The Abyssinian Scimitarbill (Rhinopomastus minor) has been observed to nest in abandoned beehives, even though it does not consume honey or other bee products.

Hoopoes are territorial, and fights between rival males (and sometimes females) can be brutal. The birds will try to stab rivals with their bills, and individuals are occasionally blinded in fights.

Hoopoes have well-developed anti-predator defences in the nest. The uropygial gland of the incubating and brooding female is quickly modified to produce a foul-smelling liquid, and the glands of nestlings do so as well. These secretions are rubbed into their plumage. The secretion, which smells like rotting meat, is thought to help deter predators, as well as deter parasites and possibly act as an antibacterial agent. The secretions stop soon before the young leave the nest.

The diet of the Eurasian Hoopoe (Upupa epops) (image 4) includes many species considered by humans to be pests, such as the pupae of the Pine Processionary (Thaumetopoea pityocampa), a damaging forest pest. Because of this, the Eurasian Hoopoe is protected by law in many countries.

A hoopoe was a leader of the birds in the Persian book of poems The Conference of the Birds ("Mantiq al-Tayr" by Attar). When the birds seek a king, the hoopoe points out that the mythological Simurgh should be the king. The hoopoe is also the king of the birds in the Ancient Greek comedy The Birds by Aristophanes.

Hornbills are the only birds in which the first and second neck vertebrae (the atlas and axis respectively) are fused together. This probably provides a more stable platform for carrying the large bill.

The casque of the Helmeted Hornbill (Rhinoplax vigil) is not hollow, as in other hornbills, but is filled with “hornbill ivory”. The Helmeted Hornbill uses its casque as a battering ram in dramatic aerial jousts. Unfortunately this has made the Helmeted Hornbill a target for poaching as a source of ivory, and the bird is now critically endangered. There are fewer than 100 Helmeted Hornbills remaining in Thai forests.

At least 546 hornbill parts, mostly casques of Helmeted Hornbills, have been posted for sale on Thai Facebook in the past five years. According to the conservation group TRAFFIC, 2,170 hornbill casques were confiscated in just three years in China and Indonesia alone. Traders will pay villagers 5,000-6,000 baht (US$165–200) for a hornbill head. Prices double or triple in cities and increase exponentially when sold overseas.

It is a belief among the Punan Bah that a large Helmeted Hornbill guards the river between life and death, and judges the worth of those who pass.

The Iban people of Borneo regard the Rhinoceros Hornbill (Buceros bicornis) (see gif above), or Kenyalang, as the king of the worldly birds, who acts as the intermediary between man and God.

The critically endangered Walden's Hornbill (Rhabdotorrhinus waldeni) is another one of the most threatened hornbills. It is presumed extinct on Guimaras and now survives only on Negros and Panay. The total population has been estimated at less than 160. Walden's Hornbills reproduce very slowly and thus are unable to survive high hunting pressures coupled with heavy logging of the rainforests. Despite already limited forest cover, deforestation still continues thanks to both legal and illegal logging, conversion into farmland, mining, and road development. Another huge threat is hunting and capture for the illegal wildlife trade. According to the Philippine Initiative for Environmental Conservation (Philincon), up to 50% of all nests in Central Panay Mountain Range were affected by poachers who would either climb up or cut down the nesting trees to poach the nestlings and the mother. Due to this high poaching rate, Philincon has devised a nest guarding program where they pay locals US$20 a month to guard hornbill nests and offer an incentive of US$11 for each successful fledged bird.

Some species of hornbills in Africa have a mutualistic relationship with Dwarf Mongooses (genus Helogale), foraging together and warning each other of nearby predators. One viral video even shows a young Dwarf Mongoose inviting a hornbill to play.

Forest-dwelling species of hornbills are important seed dispersers. The Malabar Pied Hornbill (Anthracoceros coronatus) even has a preference for the fruits of the Strychnine Tree (Strychnos nux-vomica), which contain the potent poison strychnine, making it hard for other animals to disperse the seeds.

The largest Bucerotiform is the Southern Ground Hornbill (Bucorvus leadbeateri) (image 1), at 90 - 129 cm (2 ft 11 in - 4 ft 3 in) long.