Wilkinson's World

The Hartlaub’s gull had adjusted well, perhaps too well, to the presence of humans and it is considered a nuisance within the Cape Town area. It becomes very tame and quite bold, but the main nuisance results from its raucous call and from the fouling of buildings. More serious is its presence at some airports where it can provide a risk to aircraft.

It is omnivorous and a common visitor to waste tips where it scavenges for any scraps of food. It also feeds on fish, mollusks and a wide range of small invertebrates which it often hunts while wading in shallow water. It is a very gregarious species and gathers in large numbers when feeding and when roosting overnight.

A very noisy bird, the Hartlaub’s gull has a raucous call that is not unlike that of a crow, “kwaarr”.

The Hartlaub’s gull is monogamous. A colonial breeder, it makes a nest of loosely woven sticks on rocky ground or, particularly in the Swakopmund-Walvis Bay area of Namibia, in a convenient reed bed. It will also commonly nest on man-made structures such as guano platforms and buildings. The female lays a clutch of between one and three blotched, light-brown or green eggs that hatch after an incubation period of approximately 25 days.

The scientific binomial for the Hartlaub’s gull is Larus hartlaubii; Larus from the Latin for a “gluttonous seabird”, hartlaubii after the German ornithologist and author Karl Hartlaub (1814 – 1900).

It’s never nice seeing beautiful raptors in cages, but it is comforting to know that those that are capable of being released back into the wild, will be, and that the others who could not survive out in nature, are well cared for and safe in their enormous aviaries.  The centre is also used for education and awareness purposes and has many unique and interesting displays to enlighten both school-going children and adults on the various aspects of wildlife and its rehabilitation and conservation.

What we enjoyed most was watching Liz and members of the club ring (or band) a few birds.  Bird ringing, according to Wikipedia, is “a technique used in the study of wild birds by attaching a small, individually numbered, metal or plastic tag to their legs or wings, so that various aspects of the bird’s life can be studied.”  The bird in the photo above was caught in a fine “mist net,” which is the main method used for capturing small birds for ringing.  These nets have to be manned and checked often as birds need to be released from them as soon as possible to minimize distress, injury and prevent death.

Raptors are mainly caught in Balchatri traps, lured in with live bait (such as mice or rats), but other trapping methods are also used for birds of prey, like the walk-in traps and drop-in traps.  Rehabilitated birds are always ringed before release.

The ringing procedure doesn’t take long, but a fair amount of skill and training (and a permit) is needed to do this.  There is a strict ethical code that must be adhered to at all times.  The ringers have specialized equipment to do the job and once the actual ringing has been completed, the bird is examined, measured and weighed, and accurate records are taken for submission to the birding data base.

According to the NARREC brochure, ringing projects assist with research and conservation, giving an indication of migration routes and wintering grounds of birds, tracking the movement of species and individuals, giving information on mating systems, population dynamics and the dispersal of fledglings, amongst other things.  Various organizations around the world, like SAFRING in South Africa, collate the information gleaned from the recovery of  rings from dead birds, or sightings of ringed birds, both captured or in the wild, and this is accessible and shared worldwide.

It was a fascinating visit and we urge our local readers to visit NARREC or,  if you’re further afield, support Liz in her work by donating to this worthy cause.

The South African shelduck is endemic to the southern African region and their preferred habitat is inland dams and rivers, especially in the more arid areas in the south and east of the region. Their distribution and range may be influenced through their preference for nesting in the abandoned holes made by aardvarks or other mammals.

The first part of the English name “shelduck”, “sheld” means “pied”, and elsewhere in the world members of the same family are called sheldrakes or, in the case of larger species, sheldgeese.

When they are in the water, South African shelducks feed on algae and crustaceans and when on land they feed mainly on grain such as maize and wheat.

South African shelducks often call in duet, particularly when in flight, with the male calling a loud “honk” and the female responding “hunk”.

South African shelducks are monogamous and build a nest in an abandoned burrow in the ground, usually that of an aardvark, although burrows of springhares and porcupines may also be used. These burrows provide a cool nesting area in the otherwise hot environment often favoured by the shelducks. The female lays a clutch of between six and ten eggs which hatch after an incubation period of approximately 30 days.

The scientific binomial for the South African shelduck is Tadorna cana; Tadorna from the French for “a shelduck”, and cana from the Latin for ”grey”, referring to the head of the drake. Thus the name describes a shelduck with a grey head. Can’t say clearer than that.

As we got closer we saw that this activity was generated by a male Pin-tailed whydah conducting an energetic courtship routine for the benefit of a rather disinterested-looking female perched on a branch, about four metres above the ground. They both flew off as we approached, but we positioned ourselves nearby, trying to look unobtrusive, in the hope that the pair would return and pick up where they left off. Trying to look unobtrusive was quite difficult in the absence of any cover!

In the event, the male Pin-tailed whydah and his harem had other things on their little minds and they virtually ignored our presence! The male, glorious in his pied plumage and with a tail that trebled the length of his body, buzzed after the nondescriptly brown females as if they were the most gorgeous creatures on earth. These females, for their part, very often displayed no interest whatsoever in his impressive display, and seemed to be far more enthusiastic about the seeds that they found in the grass below the trees.

Some of females were simply teasing, though, and one-by-one they flew up into the tree and perched quietly while the hormone-driven male hovered in front of them, bobbing vertically and weaving from side to side, his impressive tail waving below. It was a wonderful display to watch and we were totally enthralled. The amount of energy displayed by the little bird was amazing. Just supporting that tail up as he hovered, holding his body vertical, must have been an effort. Still teasing, some of the females would drop to the ground and the seed, seemingly unimpressed by the display.

But then one of the females decided that she was ready! She remained on her perch as the male completed his display and maneuvered himself behind her. The courtship was a drawn out affair; the mating was competed in seconds. The event looked quite violent as the male all but smothered the female, his wings hardly missing a beat as he tried to maintain his balance and position above and behind her. His enthusiasm exceeded his aptitude though and the performance was concluded when he managed to knock the little female right off her perch. Just as well birds can fly.

Each male Pin-tail has a little harem, though, and for him it was only Act One of the performance that was over. A short rest and he was flitting about looking for another female to woo. You have to stand in awe of his stamina!

We never did get any decent photos of the waterbirds.

Read more about this bird on my previous blog :    <Bird of the week :  Pin-tailed Whydah

The Pin-tailed whydah is a fairly small bird, with a length of approximately 13 cm. During the breeding season the males and females are very different in plumage, and the breeding male grows a tail that adds 20cm or so to his length. During this time the male has a black crown and back and the long tail is also black. The wings are black with white patches and the under parts, including the throat, are white. The eyes are dark brown; legs and feet are dark grey and the bill is bright red. The females and non-breeding males are similar, rather nondescript with streaked brown upperparts and white to buff under parts.

The call of the Pin-tailed whydah is a high-pitched, sustained series of “swirt swee swirt” and similar sounds. They feed mainly on grass seeds and grain, for which they forage on the ground, and also on termites.

Pin-tailed whydahs are both polygynous and promiscuous. The males are aggressively territorial, and each make has a small group of females in his territory, but these females will also mate with other males who may venture into the territory while the main man is otherwise engaged. The males mating display involves a great deal of hovering in front of the female in order to display his tail, and only about one in ten of these displays will result in mating.

They are brood parasites, and do not build a nest of their own. They parasitize mainly Common waxbills (Estrilda astrild), and the female whydah may destroy one of the waxbill’s eggs before laying one or two of her own. The eggs hatch after an incubation period of about eleven days and the gape of the newborn whydah will be similar to that of the host bird.

The scientific binomial for the Pin-tailed whydah is Vidua macroura; Vidua from the Latin for a widow, referring to the black plumage and the long black tail; and macroura from the Greek for a large tail. Thus the name describes a widow with a large tail, which does nothing to capture the essence of this beautiful little bird!

I managed to get some excellent photographs of Whydahs courting.   Read :  Courtship Routine of Hormone Driven Pin-tailed Whydahs