Photo: © Shutterstock.com/wannachat. Nicobar pigeons: even from this angle the nest looks more solid than the flakey affairs built by most species of pigeon
With its odd stocky build and ornate hackles, the Nicobar pigeon doesn’t look an ace flyer – but it is. What’s more, it is a most enjoyable species to keep in an aviary, says Bill Naylor
POSSESSING stunning iridescent and exotic tasselled plumage, the Nicobar pigeon (Caloenas nicobarica) is one of the most eye-catching and unusual pigeon species. Its gentle nature and the fact that it can be housed in groups have made it a favourite among exotic-pigeon enthusiasts.
When it’s on the ground, its long wings and dumpy shape remind you of a gamebird. Only when it’s perched on a branch does it appear to stand upright. Its most notable feature is the long hackle feathers, which encircle the neck and mantle. These are found in both sexes and are reminiscent of the ruff of hackles surrounding the neck of gamecocks. Its head is covered in a thin layer of tight dull-grey feathers, which make it look as though it has a featherless skull. This, combined with the hackles, has earned it the alternative name “vulturine pigeon”. Male Nicobars are distinguished by being larger and having longer hackles.
A dark-grey fleshy carbuncle at the base of the beak, found in both sexes, is larger in the male. The Nicobar’s plumage owes its colour to the refraction of light, producing combinations of metallic bronze, purple and green iridescence depending on light intensity. Its large purple-red scaly feet, which seem out of proportion to its body, are equipped with long nails for digging in the earth.
Owing to its habits and anatomical features, it occupies a genus of its own and is believed to be directly related to the extinct dodo and solitaire. Its closest living relatives are the New Guinea crowned pigeons (Goura species) and the tooth-billed pigeon (Didunculus strigirostris) of Samoa.
Nicobars are found in New Guinea, Indonesia, Malaya, Thailand and, of course, the Nicobar Islands. This species is frequently seen on the offshore islands of Australasia and, in 2017, one was recorded in mainland Australia for the first time. They are mobile, breeding and roosting on small, uninhabited islands and inlets, and flying to bigger islands during the day. This daily commute is mainly to avoid predators and is their key to survival, as Nicobars roost and breed in close-knit colonies, sometimes hundreds of birds.
In the wild, they feed on seeds, fallen fruit and invertebrates. In captivity, pigeon mix, millets, fruit, peas and cooked soft-maize forms their basic diet. They will eat mealworms and softfood, but too much corn can make them overweight. They don’t require fruit to be diced, but they enjoy pecking halved soft fruit, such as pears, into pieces small enough to swallow. As an aid to digestion they swallow pebbles and grit, and the gizzard is large and muscular even by pigeon standards, with the ability to digest large fruit stones. Appropriate-sized grit is required in captivity and they will swallow any small pebbles they find. Some of these stones, worn smooth by the millstone of a gizzard, take on the shiny appearance of jewellery. Indigenous tribes once wore these as jewellery and, sadly, Nicobars are killed by wildlife criminals for their “jewels”.
Despite being heavier than pigeons of a similar size, Nicobars have long wings and are very strong flyers. Consequently, they require an aviary that allows them plenty of wing exercise. In the wild, unlike most pigeons, they don’t fly in groups but in columns or single file. They breed best in groups, in which they will form pairs and are thought to pair for life. Obviously, the size of an aviary will vary depending on the amount of birds housed. A flight 25m x 10m x 3m (82ft x 33ft x 10ft) can accommodate a colony of six pairs. Nicobars breed best in aviaries with shade, which probably reminds them of their forest habitat. Evergreen shrubs, such as acuba, are ideal for providing shade and cover.
In the wild and captivity, they spend much of their time foraging on the ground among leaf litter, and so they thrive best in aviaries with earthen floors. This is much better for their feet, as they can develop foot problems on hard surfaces. A combination of coarse sand and dry organic compost provides the best medium. Above all, the aviary mustn’t be damp or muddy and a covered or semi-covered roof is advisable. Nevertheless, a natural floor will invite soil-dwelling parasites and Nicobars should be wormed at least once a year after breeding.
They will live in harmony with many types of birds, even other species of doves, which is unusual for pigeons. Species they have been kept with include turacos, starlings, parakeets, crowned pigeons, waders and fairy bluebirds.
These are highly social birds and colony breeders. Pioneering naturalists in New Guinea recorded nesting colonies of thousands of birds. In captivity they can initially be reluctant breeders, but once they go to nest they can be prolific. They appear more contented and breed more readily in groups. When I worked at Taronga Zoo, Australia, there was an aviary referred to as “Nicobar City”, which housed 30-40 pairs of dedicated breeders. The contagious stimulation to breed was obvious. At most times of the year, those birds that weren’t on eggs or feeding young would be involved in nest construction, providing a ready supply of birds for other collections. The social density of the birds didn’t cause unrest; quite the opposite. The odd squabble usually involved birds that pilfered choice sticks from neighbouring nests. Any fledglings that left the nest prematurely and ended up on the ground (a common occurrence with pigeons) would be brooded and fed by other birds.
Nicobar nests are more rigid than the average pigeon nest. Large sticks form a base, which is lined with smaller twigs and covered with grass. Like most other pigeons and doves in captivity, they also make use of baskets and nest-boxes. Ideally, these should be about 12in (30cm) square and fairly deep to allow for the large nest. They will also nest on ledges and roofs of nest-boxes, practically anywhere. The single bluish-white egg (rarely two) is incubated in the usual pigeon routine: the hen sits by day and the male by night, for 28, sometimes 30, days. For the first 10, like other pigeon nestlings, they are fed pigeon milk, a protein-rich cheesy secretion produced by both parents. Later, they are fed regurgitated fruit pulp and seeds. Initially, youngsters grow fast. Even though fledging usually takes place after 30 days, nestlings sometimes stay in the nest for up to two months. The young are darker than the adults; for the first year the tail is grey and they lack the iridescent hackles.
Being listed on CITES 1, Nicobars can no longer be traded internationally. But their long-distance movements make them vulnerable to poachers and hunters in unprotected areas. Logging now threatens former strongholds, as do introduced predators such as cats. Happily, captive populations exist in Europe, America, Asia and South Africa. There is little chance of them going the way of their extinct colony-nesting relative, the passenger pigeon (Ectopistes migratorius).
Bill Naylor has enjoyed a 40-year career in ornithology and aviculture.
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