Above: White-eyes, such as this Cape white-eye (Zosterops virens), eat a range of fruit. Wild birds often move though fruit trees piercing one fruit after another © Shutterstock.com/Simon_g

 

Known to birdkeepers chiefly by a few favourite species, the white-eyes form a large, fascinating group of Old World nectivores. BILL NAYLOR offers a necessarily brief overview

WHITE-EYES are one of the few groups of birds whose scientific name, Zosterops, is used as frequently to describe them as their common name. A white-eye’s eyes are actually dark and their name derives from the white orbital feathered ring around the eye, usually lightly edged with black, which varies in width, being largest in the African species.

The white-eyes’ closest relatives are babblers, specifically yuhinas, and the family Zosteropidae now consists of the yuhinas, some similar small babblers and the 97 species of white-eyes in the genus Zosterops. White-eyes are often viewed as the tropical equivalent of our warblers. They are found in Asia, Australia, Africa, Indonesia and numerous islands in the Southern Hemisphere. Yet the similarity is superficial. Warblers are largely insectivorous, while white-eyes are omnivorous, eating a variety of invertebrates, seeds, fruit and nectar. Similar to other nectar feeders, they have brush-tipped tongues.

The Oriental white-eye, also known as the Indian white-eye (Zosterops palpebrosus) was the most commonly kept white-eye and most frequently imported into Europe prior to the import ban. There are 11 subspecies in which the olive-green plumage varies in intensity or lacks the grey plumage, which is replaced with yellow. The chestnut-flanked white-eye (Z. erythropleurus) was a similar species frequently imported, but less so than the Oriental. It’s the only Zosterops in which the sexes are different. The male has a large chestnut brush stroke on its flank, which is much reduced in the female.

White-eyes were at one time thought of as a beginner’s nectar-feeding bird; the cheapest and easiest nectar feeder to keep. But due to the price of these birds having sky-rocketed, they are no longer considered to be a “starter bird”.

In the wild, before and after the breeding season, white-eyes congregate in loose colonies, moving from one feeding area to another, often in the company of finches and other small birds. They are frequent visitors to gardens and, if tempted with nectar, will tolerate the presence of humans. The majority of their livefood is acquired from the leaves of trees and shrubs. In captivity, foliage not only attracts invertebrates, but also provides enrichment. They do nip buds and young leaves from plants and trees, though no more than finches are inclined to do. Mealworms, wax moths, crickets and especially fruit flies, are the usual livefood provided in captivity. Birdkeepers in countries where termites occur often include these in the diet, as white-eyes are particularly fond of them.

Outside of the breeding season, white-eyes are generally kept in small groups. They are highly social birds, perching and roosting tightly together and constantly indulging in mutual preening. Pairs can sometimes be over-zealous and preen colleagues to the extent they cause feather loss. But this is more likely to occur when white-eyes are housed in cages, which is inappropriate accommodation for such an active, inquisitive bird. In the Far East, they have been kept as song birds for centuries. Only the males sing, usually prior to and during the breeding season.

Carotenoids in food will enhance the colour of the plumage. It’s rarely seen now, but when deprived of a varied diet the white-eye’s green-yellow plumage becomes dull and faded. Feeding white-eyes is very easy; they are inquisitive birds and will sample any food. A softbill mixture should ideally form the basis of their diet to ensure they are getting a balance of nutrients. They are fond of all fruit and particularly like oranges; they also pierce grapes and drink the juice. There is no need to dice fruit, since they will peck pieces from virtually any halved fruits, as well as probing to drink the juice.

Fruit is often provided daily, impaled on nails affixed to branches. White-eyes’ predation on cultivated fruit is notorious; in the wild, they move through fruit trees piercing one fruit after another and these small, industrious birds are considered a pest in a number of fruit-growing areas.

Some birdkeepers supply plenty of juicy fruits and mix honey with the softbill mixture, under the impression that they don’t have to provide extra nectar. Although white-eyes can be kept on a nectar-free diet, they do benefit from it. In the wild, they drink nectar by inserting their beaks into the trumpet of the flower or, as flowerpeckers (Dicaeidae) do, pecking a hole in the base of the flower.

Nectar should always be provided in a nectar-feeding bottle; if placed in an open dish they will usually try to bathe in it. A pond or appropriate-sized water receptacle is appreciated, as they are enthusiastic bathers, drenching themselves at each session and bathing several times a day, even in winter. In the wild, they eat tree and plant seeds and are pollinators of a number of plants species. In captivity, they will also eat small seeds.

White-eyes have a reputation for not being easy to breed and, in an aviary, this is often the case. However, in well-foliaged tropical free flights and tropical botanical collections, where they are frequently kept for biological control of invertebrate pests, as they have proved to be free breeders.

White-eyes become territorial and aggressive when nesting. Both sexes take between four and seven days to build a tight cup nest, resembling that of a sunbird or hummingbird, constructed from mosses and fine grasses, held together with spider webs and lined with hair or wool. The nest is either slung on the end of a slim branch or nestling in ivy or hanging plants. Two or three turquoise eggs are incubated by both sexes for 10-12 days, with eyes open after four days.

The youngsters have feather tufts on their heads and are very small, but they can be successfully hand-reared on diced pinkies, mealworms and pureed fruit baby food. Hand-reared birds don’t become imprinted. They fledge at between 10 and 13 days, fly well after fledging, and are feeding independently after three weeks.

A new nest is constructed for a second clutch a week after the first youngsters have fledged, while one parent continues
to care for the brood from the first clutch. Insect food must be provided regularly or the second clutch will fail. Young birds can breed within the first year, at nine months old. There is an interesting account in the Avicultural Magazine Volume 68 (1962) about this species being bred at liberty in the early 1960s, nesting in a nearby pear tree. The male disappeared when the hen was incubating her eggs. A second male released from the aviary immediately assisted in parental duties and a single youngster was reared.

A hardy species
Provided they have heated indoor quarters in the winter, white-eyes can be kept in an outdoor aviary, but have a tendency to roost out of doors in foliage. Though few modern keepers of white-eyes in the UK would allow their birds to roost outside in the winter, they are robust and do acclimatise. In the 1850s one of two species of Australian Zosterops (Z. lateralis) naturally colonised New Zealand over 2,000 miles away, where they are known as silver-eyes. They subsequently spread to virtually all nearby islands and survive the cold New Zealand winters on South Island, where temperatures can plunge to ten below freezing.

Bill Naylor has enjoyed a 40-year career in ornithology and aviculture.

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