| |
Diederik Cuckoos are
sometimes confused for Klaas’s Cuckoo, but does not have the white patch
behind the eye and green half collar that extends onto the sides of the
breast in the male.
They have a very
distinctive persistent, plain-tive song of 5-7 high-pitched fluty whistles - dee-dee-deederik, rising and falling in pitch, repeated at regular
intervals. Introductory dees may vary in number and song may be followed by
shorter rapid di-di-di-di-di falling in pitch. In display, males give a
wavering weah-weah-weah- weah when presenting food to a female. Females solicit
courtship feeding with a deah- deah-deah-deah call.
Diederik Cuckoos are
found throughout South Africa but are largely absent from central and north
western Karoo and the Namib Desert.
They normally
inhabit the Forest edge and open arid savannah and more mesic savanna and
closed woodlands, drainage-line woodlands, semi-arid scrublands, parks and
gardens. However, they are uncommon in mopane woodland.
They are normally
solitary or in pairs but are conspicuous in the breeding season with the
males calling for extended periods from prominent perches. Females are less
conspicuous, but are often seen in interactions with males.
The sexes are similar in colour. The head and back is a
metallic green with bronze patches on the back of head and nape and a stripe
on the mid-crown. The forehead and supercillium is white and the wing
coverts are a glossy bronze green with large white spots. Wings are
blackish with white bars across the inner vane of primaries. The tail is a
dark green with white tips and white spots along both edges of the rectrices.
The central pair is without spots. The belly flanks, thighs and under-tail
coverts are white with green bars and the underwing coverts are darker with
white bars. The bill of both sexes is black and the eyes and eye ring is red
with grey legs and feet.
Adult females are
similar in colour to males, but duller, with or without the streak on the
forehead.
As with the adults,
the juvenile sexes are also alike. The back is a dull green or bright rufous
colour or intermediated with green and rufous bars. Some birds are rufous
only on the crown, and have pale spots on their upper wing coverts (except
in the rufous-phase). Their undersides are white with dark greenish or
rufous streaks on the breast and belly and blackish or dark green spots. The
bill is coral red and the eyes are grey to brown. Legs and feet are dark
brown. The eye ring becomes red while the birds are in juvenile plumage.
Their diet consists
mainly of hairy and smooth caterpillars, including the Chestnut Eggarlet
Anadiasa punctifascia, the caterpillars of which occur in a protective
woolly cluster, second stage larvae of Mopane Emperor Moths (mopane worm)
Imbrasia belina, larvae of the Barred Eggarlet - Bombycomorpha bifasciata,
larvae of distasteful Acraea species, termites, grasshoppers and adult
butterflies and the contents of host eggs removed during laying.
Caterpillars are
grasped near the head, and shaken to get rid of the guts. Juviniles have
been feeding on a caterpillar by skinning it by holding it at one end,
flicking it until the skin separates from the body, then shaking it so that
the skin comes off.
As with many
Cuckoos, the Diederik Cuckoo is brood parasitic. Females are probably
territorial, defending a colony of potential hosts from other females.
Males seem to range across female territories. |
|
In aggressive, male-to-male
competition for access to females, males chases another male, sometimes for
30 minutes or longer, flying with rapid, deep wing beats, calling a fast,
high-pitched version of the Diederik song.
Males may also
pursue females in a rapid twisting flight. In their advertising display,
males call day after day, in the early morning and late afternoon from a
regular call site, a prominent perch close to potential host nests, to
attract females. In courtship, males feed females caterpillars (so this is
what chocolate bearing human males are mimicking!).
In courtship feeding
behaviour, males fly to females with wings stiff, fluttering and kept below
horizontal, constantly calling. While perched with a caterpillar, males give
a low-pitched weah-weah-weah-weah and females respond to the males with a loud
deah-deah-deah-deah, rising in pitch and amplitude. During the courtship
feeding the males perches near the female while facing her and leans
forward, tail spread and held down. He bobs his head up and down, or swings
his head from side to side while presenting the caterpillar. The female
leans back and then forward to take the caterpillar, wipes it on her perch
and swallows it.
Diederik Cuckoos use
a wide range of host species in South Africa as foster parents. These hosts
are mainly Southern Red Bishop, Southern Masked-Weaver, Cape Sparrow, Cape
Weaver, Cape Wagtail, Village Weaver Lesser Masked-Weaver, Spectacled
Weaver, Yellow Weaver, Chestnut-vented Tit-Babbler, Golden Weaver,
Golden-breasted Bunting, Karoo Prinia, Red-headed Weaver, Mountain Wheatear,
Southern Grey-headed Sparrow, White-winged Widowbird, White-browed
Scrub-Robin, Karoo Scrub-Robin and Great Sparrow. Other hosts include Marico
Flycatcher, African Paradise-Flycatcher, Kalahari Scrub-Robin and Rattling
Cisticola.
Small colonies of
Southern Red Bishop are disproportionately more frequently parasitized than
large colonies. It is thought that this is due to the fact that the female
has to be furtive when laying the egg and getting rid of one of the host
eggs. With may eyes around, this may be a bit more difficult to achieve in
the short time span the Cuckoo has while the hosts are away.
Females usually lay
only 1 egg per nest, very rarely 2. Females may lay as many as 20-24 eggs
in a breeding season which lasts for approximately 10-12 weeks. Females
will match the size, look and feel the specific host’s eggs.
Newly hatched young
are naked, pink skinned which rapidly darks to a blackish colour and is
largely black at 3 days. The bill is pink and broad gape, deepening in
colour with age. The edge of the gape is yellow. The eyes are grey,
changing to brown as the chick matures.
The chick evicts the
host’s eggs and young at 2 days old and continues until they are all gone.
Eyes start opening on 7 days and are fully open by 10 days.
The young cuckoo
remains with it’s hosts for around 21 days after fledging. Nestlings raised
by bishops are largely independent when they leave the nest and are not fed
by the host. Young cuckoos in nests of bishops are reared in part on seeds,
at least late in their nestling period. Weaver hosts feed mostly
invertebrates, especially insects.
|
|
