Understanding Waxbill Behaviour.

MUCH has been written on the care and keeping of waxbills
in captivity but there is a dearth of information on why
these wonderful birds behave in the way they do. In this
article I aim to help shed some more light on these and
other estrildids, and much of the information can be applied
to finches in general.

Although most waxbills are primarily seedeaters not every
species will rely on grass seed for its subsistence diet,
eating other plant seeds instead. Nevertheless, almost all
will partake of it some of the time and most will eat it most
of the time. Only the aberrant allies the antpeckers,
nigritas and olivebacks, with one exception, are truly
independent of any plant seeds (though the seeds found in
fruit are consumed by some species), because these have
developed specialised feeding habits more akin to insectivores
and frugivores.

The exception is the white-collared oliveback (Nesocharis ansorgei), which is believed to feed entirely on the seeds of the composite quarantine weed (Melanthera scandens). Those waxbills that are heavily dependent
on grass for food lead lives inextricably linked to it in other ways. Besides the provision of seeds, the grass yields up succulent young shoots and abounds with tiny insects.

The grass also affords the waxbills protection - foraging for seeds that have fallen to the ground means they are often free to eat while remaining hidden from predators. Finally, its long leaves and inflorescences are gratefully accepted for use in nest construction.

The grass family is one of the largest in the plant kingdom and contains about 10,000 species. Fundamental to its growth is good light; it cannot survive in the deep shade of a forest.

Some species of waxbilllive and breed on the forest edge and so are able to dart quickly into the bushes and trees at the first sign of danger. However, for sustenance they, too, rely on the grass seeds and its harboured community of aphids, bugs and beetles like their cousins who prefer or have to feed in the open. To survive, the grass and its insect community needs water and this comes with the rains. During and after rain the grass immediately undergoes a remarkable transition. Green leaves are produced within a day or so, followed by fresh ripe and half-ripe seeds. The insects, taking advantage of this succulent fresh vegetation to munch and sap to suck, are fast stirred into action. So, too, are the waxbills. With food of the right kind abundant, they are stimulated to breed.

Hard seeds, which are unlikely ever to be as hard as the commercially available type, are overlooked in favour of the ripe and half-ripe ones, while the infinite number of insects makes easy pickings for any birds with a growing family of hungry nestlings.

Protein is essential for the rapid and healthy growth of the young and that found in seeds is augmented in a form that may be assimilated quickly and easily. It is also a form that only a soft-bodied insect can provide, and which the parents are able to regurgitate to their offspring quickly for the best results.

The chicks are really getting two meals for the price of one, because the insect's innards will inevitably contain some nutritious undigested plant matter.

In the wild, waxbills ordinarily drink several times a day. The violet-eared waxbill (Uraeginthus granatina granatina), however, has been recorded as living for six months or more in areas bereft of surface water. In all likelihood moisture is being obtained through its diet of termites.

This is borne out by Mark Anderson, a nature conservation scientist in South Africa's Northern Cape Province, who told me that he measured the water content of the snouted harvester termite (TrineIVitennes trineIVoides) every month for a year.

The termites were 70-80 per cent water (the moisture content of the workers being about 10 per cent greater than that of the soldiers). It is possible waxbills in other arid areas obtain moisture in a similar way.
As is found with most other birds, waxbills usually drink by dipping the bill into the water then lifting the head and tilting it back to swallow, but some also appear able to suck up water pigeon-fashion. Looked at more closely, this sucking consists of continuous scooped doses entering the oesophagus in a way similar to that used by zebra finches (Taeniopygia guttata castanotis).

Drinking method.
IN SUCH a case the bill is kept in contact with the water for a longer period and without the need for the head to be lifted repeatedly. Generally, the sucking method is used when there is a small or shallow area of water, such as a droplet left on the leaf of a plant after it has rained or been sprayed.

Estrilda and cordon-bleu species are particularly adept at imbibing water in this manner. All waxbills love to bathe in water, though it is not known how frequently this action is performed in the wild. Captive birds tend to bathe daily and, providing there is enough surface water, the likelihood is the wild bird does also. For example, ten minutes after a summer thunderstorm had passed a green-winged pytilia (Pytilia melba) was observed by Dr Skead bathing in a roadside pool where previously there had been no water.

Usually, bathing starts off with some hesitation and apparent nervousness, possibly a reaction to a fear of lurking predators or the uncertainty as to the depth of the water. But once a bird starts to bathe, it is soon joined,
especially in captivity, by conspecifics and other species. Indeed, if the bathing dish is too small to accommodate all the birds at once they are apt to queue up or jostle each other to find a place in the water.

After bathing the bird flies to a relatively safe perch and dries itself by shaking and ruffling its plumage and by vibrating its wings and tail. Preening and oiling of the feathers always follows bathing.

Preening consists of a number of different movements that tend to be carried out in an orderly sequence and at great speed. Immediately after bathing a waxbill will shake its body and whirr its feathers to rid its plumage of excess water.

The bird then usually wipes its bill on a perch before extracting a waxy and fatty oil from its preen gland (a prominent gland found in most species of birds located above the root of the tail and covered by overlapping feathers). Then it smears the substance over its feathers. The oil seems to keep the feathers from becoming brittle and it also has anti-bacterial and fungicidal properties. Research is being undertaken into these properties and the anti-parasite and possible pheromone content.

As the bird needs to regain full powers of flight as quickly as possible the pinions are preened first, with the remainder of the plumage being dealt with in a more leisurely fashion. The whole session may only take around 20 minutes and ends with a vigorous shake of the body to settle the feathers.

Debilitating moult.
DESPITE the daily servicing of the feathers they will still wear out eventually. Continual abrasion against foliage or the ground, continuous rubbing in the nest and flying itself all take their toll on the plumage. The old set of feathers must be replaced as quickly as possible, but it must be done at the best time for the bird, which is when it is not breeding and at a time when it avoids the coldest periods, or other periods when food is short.
The moult is a time of increased energy expenditure as new feathers have to be manufactured.

For a waxbill this is the equivalent to more than a quarter of its total body protein, so it will need to eat more food to replace the energy lost as heat through the patchy feather covering.

Flying also becomes more strenuous due to the gaps in the wings. New flight feathers are distinguished by their fresh appearance, and the gap between the worn, faded feathers is partly filled by the 'pin' or growing feathers that are still in their waxy sheaths.

When a feather is about one-third grown it breaks out of the waxy sheath and before long attains its full length. A short time later the blood supply to the new feather ceases and it becomes a dead structure, the sequence continuing down the line of feathers.

As each new feather is half-grown, its old neighbour drops out. If the bird has been fed a nutritious diet during the moult and is also allowed ample exercise the moult is usually accomplished quickly and problem-free.
All waxbills seem to enjoy sunbathing, and the benefits of this are believed to include the removal of ectoparasites and the absorption of vitamin D, so captive birds should be given every opportunity to sunbathe. However, plenty of shade should also be made available because, in hot weather, many waxbills prefer to spend the hottest hours of the day under cover.

At one time it was believed that estrildine species did not indulge in dust bathing - even species of arid country - and I have to admit to never having seen any of my own birds dust bathe.

Russell Kingston, who has a bird farm in Queensland, Australia, recommends providing an earth floor for captive cut-throats because, he says, they enjoy a good dust bath.

Kingston's cut -throats were housed in a fully roofed aviary that prevented the earth from getting wet. The birds were seen dust-bathing.

Anting' is the term coined for the act of a bird rubbing ants into its skin or feathers. This act is known to be performed using, for example, a centipede or millipede, or even a camphor ball or pungent fruit. It is known to have been performed by some waxbills but does not seem to be widespread in the group as a whole.

After assuming the characteristic anting posture, the bird sweeps the insect or object over the inner surface of its half-spread wings or the underside of its tail and anoints these feathers with formic acid, or some other secretion, and then drops or swallows the insect. It is unclear as to the real function of this behaviour but is commonly believed to help control ectoparasites, keep the feathers in good condition and to provide some form of stimulation.
Unlike the true finches, which construct open cup-shaped nests, waxbills generally build structures that are completely enclosed without any firm anchoring attachments. These can be removed quite easily in their entirety from the vegetation in which they have been built.

Nesting materials.
DRY grass and other fibres are used for the outer shell and softer finer grasses, inflorescences and feathers, usually white, form the lining. Such nests are typically described as being globe-shaped with an entrance hole on the side, but the truth is most are irregular in shape more or less rough ovoids with the axis slightly tilted - and frequently built among stems, leaves, or branches.

Invariably, the entrance faces where it best provides clear views of the nest for the approaching male or female, and affording best views of the vicinity when exiting. In this sense it is at the front, but the entrance is anything but a simple hole. Several species (though not always) construct a long, downward-sloping tube-like extension to the nest entrance, which can vary in length between species and even between conspecifics. At times an overhanging porch or canopy may be built over the entrance hole.
Many of the typical Estrilda waxbills take nest-building one step further and construct an elaborate second storey nest on top of the real nest and 'decorate' this and the outer layer of their nests with small odoriferous objects.

_{source Bird Keeper Mag.}