Garden gems
Text: Tim Jackson. Photography: Various. Article from the August 2013 issue of Africa Geographic Magazine.
As birds go, sunbirds must be among gardeners’ favourites. Why? Well, apart from being seriously attractive, they go for gaudy flowers, particularly in the red spectrum. And that, explains science editor Tim Jackson, gives gardeners the perfect reason to grow brightly coloured flowering plants that will attract these little beauties.
Wherever you may be in sub-Saharan Africa, there’s a good chance you’ll have sunbirds in the garden. In nature, these diminutive birds occur in a wide range of habitats. There is, for example, the dry-country dusky sunbird of the semi-arid coastal plains, dry savanna and Karoo scrub of south-western Africa, or the orange-breasted sunbird, a fynbos specialist restricted to South Africa’s southern and south-western regions. At the other extreme is a species like the northern double-collared, a forest sunbird that frequents densely vegetated areas such as Bwindi Impenetrable Forest in Uganda and the montane forests of East Africa, or the red-chested, which occurs near rivers, marshes and lakes in Uganda.
And whereas species such as these may have relatively specific habitat preferences, others are much more cosmopolitan. The amethyst sunbird occurs in the miombo and baikiaea woodlands of Malawi and Zambia but is equally at home on hills covered in flowering aloes and proteas in the Eastern and Western Cape provinces of South Africa respectively. Of course, all these species also thrive in gardens. In Harare, Zimbabwe, variable sunbirds have found the suburban set-up so much to their liking that they have become the most common sunbird in the city.
Sunbirds may be as noticeable by their absence as by their presence – in other words, they can be seasonal. In Gauteng, South Africa, gardens well stocked with flowering plants teem with these busy little birds in winter and spring, but come summer the sunbirds have mostly gone. Similarly, in Knysna in the southern Cape, southern double-collareds suddenly appear in June as the aloes begin to flower. In Uganda, bronze sunbirds are found in Kampala gardens from December to April and then disappear.
Such movements can be attributed largely to the fact that sunbirds are great travellers in their search for the best areas to feed in at any given time of the year. And some are greater travellers than others: a malachite sunbird has been logged flying more than 500 kilometres in its quest for food, whereas collared sunbirds have been recorded moving no more than a few kilometres.
Some species are altitudinal migrants, like the amethysts that, depending on the season, fly some 26 kilometres from the suburbs of Lydenburg in Mpumalanga, South Africa, into the nearby mountains – and back again. East Africa’s golden-winged sunbirds are also climbers, shifting up and down mountains in accordance with flowering times.
Response to rainfall is another factor underlying movement. On Zimbabwe’s central plateau, scarlet-chested sunbirds are seen in suburban gardens during the dry season, having arrived probably from northern Botswana. There are similar influxes in Kenya when it’s dry, whereas in Namibia scarlet-chesteds tend to move in during the wet season.
The prize for aggression must go to the malachite sunbird, which has been known to attack birds as large as an Egyptian goose
Of course, the follow-the-food imperative is at work even during the season of bounty. Where supplies are localised or patchy, sunbirds are opportunistic and move around in search of rich pickings. Malachites in particular tend to be nomadic if there is a shortage of flowering plants where they are; in South Africa they have been recorded travelling as far as 150 kilometres and in Kenya they wander altitudinally.
Sunbirds’ breeding behaviour can be quite entertaining and is worth watching if you’re lucky enough to have them nesting in your garden. The males are energetic about guarding their territories (and their mates), and often sing from a prominent perch in their patch. Scarlet-chesteds, for example, are well known for proclaiming their space from a conspicuous branch. They readily chase other birds away, be they rival males or members of other species. Tacazze sunbird males defend their territories against malachite males where both species occur in East Africa, while bronze sunbird males chase away all-comers in the sunbird world, and even other species such as African paradise flycatchers and village weavers. Copper sunbirds can be extremely territorial too, attacking other garden birds such as Kurrichane thrushes, common fiscals, dark-capped bulbuls and house sparrows. The prize for aggression must, however, go to the malachite sunbird – he has been known to attack birds as large as an Egyptian goose!
Posturing and display are an important part of the aggression, and in many species the flashing of yellow pectoral tufts is part of the show. In orange-breasted sunbirds, raising the feathers on the back of the head signals a mild threat, whereas stooping forward with wings and tail held down stiffly means that the male really means business. Greater double-collared males perch about 30 centimetres apart and sing at each other, swaying from side to side. The display of an adult male amethyst faced by a juvenile is particularly bizarre: he advances upon the younger bird with a butterfly-like flight, wings flapping slowly and body moving at an angle down towards the upstart.
In some instances threat displays may escalate into fights. Amethyst males are sometimes seen flying at one another, interlocking their claws and ‘fencing’ with their bills as they tumble towards the ground.
Male-female interactions are no less fascinating. Male malachites mate by flying vertically and then hovering over the female before dropping down to copulate, wings quivering rapidly. Their habit of mating with more than one female if given half a chance goes a long way towards explaining the aggressiveness between males. And in malachites, as in a number of other sunbird species, cloaca-pecking is associated with courtship. The function of this behaviour is possibly to remove any packets of sperm in the female’s cloaca that had been deposited by a rival.
In collared sunbirds, the male’s courtship display involves leaning slightly forward and then jumping from side to side on his perch, calling and flapping his wings as he does so. The amethyst male has different tactics: he hops around dropping first one wing and then the other, then both at once and finally fluttering each one.
One of the most acrobatic displays of all is that of the miombo double-collared sunbird, in which the male swings upside down on a perch while singing to a female with nest material. Together, the pair pivot very quickly in half or full circles on the perch for as long as five minutes.
Pre-copulatory bowing follows, the male singing all the while, and then the pair face each other, bow, throw their heads back – and repeat the sequence for 10 seconds before mating.
When it comes to nest-building, it’s mainly the female that collects material and fashions it into a structure, although she is almost always accompanied by her mate. He makes no attempt to assist her, but is more likely ensuring that no clandestine mating takes place. Only variable sunbird males participate in constructing the nest.
The structures generally comprise grass and other fine material like rootlets and lichens, are held together with spider web and have a soft lining on the inside and some form of decoration on the outside. In the main,they are pear-shaped and enclosed, and in many species the entrance hole is protected by a porch. Nests tend to be suspended, and in suburban environments they have been found hanging from a rope in a disused room (collared sunbird), from an electric flex and a clothes line (amethyst) and from an iron bar (scarlet-chested). Thorny bougainvillea shrubs make attractive nest sites for garden sunbirds.
One of the most acrobatic displays is that of the miombo double-collared sunbird: the male swings upside down on a perch while singing to a female with nest material
Malachite and southern double-collared sunbirds can take up to 30 days to build a nest, whereas the olive and scarlet-chested are much faster, completing the task in as little as two days and three to six days, respectively. The fact that the female scarlet-chested has been recorded stealing material for the lining, especially feathers, from the nests of penduline tits and variable and purple-banded sunbirds may explain her speed. The structure’s outer decor often reflects its suburban location, with scraps of paper, silver confectionery wrappings and bits of plastic added to the mix.
Having built their nests on their own, female sunbirds also incubate their eggs without help from the males. This stage in the breeding cycle lasts for two to two-and-a-half weeks, depending on the species. A crooked tail seen on a female orange-breasted sunbird is a giveaway that she is incubating, as her tail is twisted to one side while she is in the confines of her nest.
Males finally take up parental duties when the chicks hatch, helping to feed the youngsters both in the nest and after they have fledged. Food items for their fast-growing progeny include small moths, beetles, aphids, grasshoppers, fruit flies, spiders and nectar. Keeping the nest clean is also part of parenting, though the chicks of bronze sunbirds do their bit by poking their beaks out of a hole they make in the back of the nest while presenting their cloacas at the entrance so that their parents can more easily remove their faecal sacs. Even after fledging, chicks continue to use the nest for sleeping for a few days or, in the case of malachite sunbirds, as long as a couple of weeks.
In many species, the pair have two or more breeding attempts in one season, and bronze sunbirds in the tropics may even have five broods a year. Pairs of this species remain together outside the breeding season and it is believed they mate for life – there are records of at least one bronze sunbird pair that nested together 15 times over a four-year period.
When not breeding, sunbirds tend to be fairly relaxed and in many species pairs and small groups may be seen together. Collared, green-headed and orange-breasted sunbirds are generally gregarious and where there are rich pickings for all – a coral tree in flower, perhaps, or a bed of wild dagga in full bloom – they are often seen in association with other sunbird species.
Filling the garden with indigenous flowering plants is a sure way to attract sunbirds. Red is a favourite colour, but orange, yellow, purple and blue flowers will also bring them in. And the plant can be any size, from a tree – like tree fuchsias and coral trees – to a shrub, such as wild honeysuckle, strelitzia, wild dagga, red-hot poker and most aloe species. Some acacia trees, which are themselves attractive to sunbirds, bring a bonus in the form of parasitic mistletoes, whose flowers also provide nectar. And if you want to supplement the plants’ bounty, you can also dot nectar-feeders filled with a sugar solution around the garden. (Send in a photo of birds in your garden and you could win a Takalani feeder; see page 79.)
Most sunbirds honour their ‘deal’ with plants by inserting their tongues down the flower’s corolla to probe for nectar – and thus do their part in pollination. Some, however, are cheats, accessing the nectar through a hole in the side of the corolla. The copper sunbird is a notorious nectar robber, as are the amethyst and miombo double-collared, which steal from hibiscus flowers. Scarlet-chesteds shortcut their way into the large, red flowers of the sausage tree, and southern double-collareds do likewise into strelitzia flowers.
Most sunbirds perch when foraging on flowers but some, like amethysts and miombo double-collareds, sometimes hover in front of the flower as they access the nectar. White-bellieds are even noted for being able to fly backwards as they hover.
But nectar isn’t the only bounty for sunbirds. Green-headeds feed on the sap from oil palms, while both southern and greater double-collareds are partial to the fluid that oozes out of figs where fig wasps have tunnelled out of the fruits. Greater double-collareds also feed on the juices of fruits such as figs and grapes.
Insects and other invertebrates, including butterflies, moths, grasshoppers and flies, also make up an important part of the sunbird diet, and there is even a record of a malachite feeding on small lizards. Green-headed sunbirds are so partial to spiders that one has been recorded with no fewer than eight in a single beakful. In fact, spiders get a rough deal from sunbirds: they are eaten by the birds, their webs are key building blocks in sunbird nests and some species, notably the scarlet-chested, also rob their webs of trapped prey. Bronze sunbirds have been known to enter an occupied classroom to feed on insects and spiders in the cobwebs.
Well adapted to the garden setting, amethyst sunbirds have been observed scouring rose bushes for aphids, and other species probe the bark of trees for insects. But most sunbirds hawk insects from a perch or, in the case of the bronze sunbird, catch them in free flight. Golden-winged sunbirds, too, regularly catch flying ants in mid-air. In contrast, orange-breasteds sometimes go the terrestrial route and feed on the ground.
Although sunbirds are accustomed to bathing in the dew or raindrops that collect on leaves, they will make good use of a birdbath in the garden. And while some birds may be fazed by irrigation systems and garden sprayers, malachite and southern double-collared sunbirds happily bathe by flying through the jets of water. Not only are sunbirds both attractive and interesting, but they have adapted well to living around humans – and there seem to be 101 ways in which you can lure them into your garden.
Sunbird enemy no. 1
With a range covering almost all of sub-Saharan Africa excepting the arid parts of Namibia, Botswana and South Africa, Klaas’s cuckoo cuckolds many of the continent’s sunbirds. These cheats are prodigious egg-layers too; a single female lays about 24 eggs per breeding season, one per host nest, and removes one of the host’s eggs when depositing her own.The cuckoo’s incubation period is shorter than that of the host species, enabling the newly hatched cuckoo chick to evict the host’s eggs and any small chicks from the nest.
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