#paleognaths

If you have poor eyesight, you have something in common with the kiwi! This species of bird is nocturnal, and they rely on other senses light smell and hearing to find their prey. As a result, most kiwis have extremely poor vision, and there's even small but healthy population of completely blind individuals. The best part? Scientists believe the gene responsible for the reduction in vision is the Sonic hedgehog gene.

(Image: A North Island brown kiwi (Apteryx mantelli) by Tui de Roy)

Carve Out Some Time for the Cassowary

Famous for their bright colors and short tempers, cassowaries are a group of flightless birds in the genus Casuarius. There are three species: the Northern Cassowary (C. unappendiculatus) which is found in New Guinea; the Southern Cassowary (C. casuarius), native southern New Guinea and northern Australia; and the Dwarf Cassowary (C. bennetti), endemic to New Guinea and the surrounding islands. All three species prefer tropical forests, though they are known to venture into savannahs, wetlands, and suburban areas in search of food.

Cassowaries are mainly active at dawn and dusk, and spend the time in between in their nests-- large pads of vegetation built on the ground. They opportunistic omnivores; their primary source of food is fruit and fungi, but they will also eat insects, frogs, fish, birds, small mammals, and carrion when available. Much of the fruit they eat is swallowed whole, which makes cassowaries invaluable for spreading seeds throughout their range. Additionally, due to their large size, adult cassowaries have no natural predators, and will aggressively defend their young from predators like snakes, monitor lizards, birds of prey, and wild dogs. When startled this birds can run up to 50 kph (31 mph), or lash out with their powerful legs.

Members of the Casuarius genus are solitary, save for the reproductive season. This season runs from May to September, when fruit is most abundant. Males maintain and defend territories, and call to attract mates. These calls are extremely loud, and at one of the lowest frequencies of any known bird, at about 23 Hertz. When a female approaches, the male crouches and allows the female to inspect him. She may also chase him, typically into water where the two perform a ritualistic fight before she submits. After laying her eggs, the female will move on to another male’s territory.

The eggs are extremely large and bright green, and usually laid in clutches of four. The male alone tends these eggs, incubating them and maintaining the nest for 50-52 days. The chicks that emerge stay with him for an additional 8-9 months until they become independent. Individuals take up to three years to become fully mature, and the average lifespan of wild Casuarius is anywhere from 30 to 50 years.

Southern Cassowaries are the largest of the three species, at up to 1.8 m (5ft 11 in) tall and weighing 58 kg (130 lbs) on average. Females tend to be much larger than males, and the species is considered to be the largest in Asia and the 3rd largest in the world. The Dwarf Cassowary, as the name implies, is significantly smaller at only 1.5m (4ft 11in) tall and 26 kg (57 lbs) at maximum. Northern Cassowaries lie between the two extremes. While all three species have black bodies, the coloration of their heads and necks vary significantly. Both the Northern and Southern Cassowary species have wattles-- pouches of skin that dangle from the neck-- that can be red, gold, purple, or white, which contrasts sharply with their blue necks. The Dwarf Cassowary lacks a wattle, and has a darker blue neck. In addition, it has the smallest head crest, or casque,; the Southern Cassowary’s casque is blade-shaped, and larger than the Dwarf Cassowary’s. The Northern Cassowary’s casque is more flared, and the largest of the three species.

Conservation Status: The Dwarf and Northern Cassowary species are considered Near Threatened and Least Concern respectively by the IUCN, while the Southern Cassowary is classified as endangered. All three are threatened primarily by habitat loss.

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Photos

Steve Parish

Kevin Schafer

Contrary to what you may see in cartoons, ostriches don’t bury their heads in the sand when frightened. The myth may stem from their nesting habits; parents dig holes in the ground for their eggs, and regularly turn them throughout the day.

(Image: An common ostrich couple (Struthio camelus) by Yva Momatiuk and John Eastcott)

Renowned Rheas

A distant cousin to the ostrich and the emu, rheas or ñandus are a group of birds belonging to the genus Rhea, consisting of the common rhea ( Rhea americana) and the lesser rhea (Rhea pennata). Also included as either a subspecies or a seperate species is the puna rhea ( Rhea tarapacensis). This group is found in the southern half of South America, typically in open grasslands or sparse woodlands.

Like their flightless relatives, rheas are large, flightless birds characterised by a small head, long neck, and long legs. Adults of the common rhea species can reach up to 1.5 m (4 ft 11 in) tall and 27 kg (60 lbs), while the smaller species only reach 1 m (39 in) and 29 kg (63 lbs). All members of the rhea group have dull grey or brown coloration. Males are typically larger than females, although both possess large clawed feet which are used for outrunning or out-kicking predators like cougars (Puma concolor) and pampas cats ((Leopardus colocolo), which often go after nests or chicks.

Rheas are largely herbivorous, and spend most of their days grazing. Their diets consist of grass, cacti, saltbrush, and the occasional small lizard or insect. Outside the breeding season they can be found in flocks of 10-100, with individuals taking turns watching for potential threats while the others graze. During the breeding season, from July to January, males fight each other with their sharp claws and beaks to gain dominance. The victor mates with up to 12 females, each of which produces a clutch of 20-40 eggs each season.

 Once the eggs are laid, the males provide all the care for the offspring. These eggs are laid once every 48 hours, and most are moved to a nest for protection. However, some eggs are left to rot, and the flies they attract serve as food for the brooding males and their chicks. Eggs take about 30 days to hatch, and the young are taken are of for an additional six months. Rhea fathers are extremely territorial, and will become aggressive even towards other females, all while guarding several broods of chicks. Once they reach independence at six months old, chicks join a group of young adults, though they don’t become sexually mature until they’re about two years old. In captivity individuals can live up to 13 years.

Conservation status: The greater rhea is considered Near Threatened by the IUCN, while the lesser rhea is classified as Least Concern. Their main threats are habitat destruction and increased hunting and nest poaching from humans.

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Photos

Dave Curtis via eBird

Konrad Wothe