Extreme foster care

Last weekend we spend a glorious two days at Walkersons outside Dullstroom on the way to Lydenberg in Mpumalanga. As is usually the case in this area the weather can be highly variable. We were fortunate enough to get one blue sky early morning.

‘Look deep into nature, and then you will understand everything better’

 Albert Einstein

One of the species of birds I have found difficult to see, let alone photograph, have been Cuckoos. You would think that with fifteen types of Cuckoo seen in southern Africa  there would be common sightings, but there are not. You are more likely to hear them especially the Red-chested, Klaas and Diderick Cuckoos which are often heard but seldom seen.

Most of the Cuckoos seen in southern Africa are large, between 28cm and 40 cm. The largest Cuckoos are the Striped and Great Spotted being between 38 and 44 cm. The next smallest group of Cuckoos are around 28mm to 34 mm in size and include the Common, African Red-chested Black, Thick-billed and Jacobin. The smallest Cuckoos are the green Cuckoos, the African Emerald, Klaas and Diderick Cuckoo.

The Cuckoos you hear most often are the Red-chested Cuckoo also called the ‘Piet-mevrou’,  an onomatopeic name. You will also often hear the Diderick and Klaas’s Cuckoo. Last Saturday morning, I was fortunate enough to see a Common Cuckoo chick being fed by a female Cape Wagtail. The African and Common Cuckoos are difficult to distinguish apart without hearing the African Cuckoo’s call or seeing the markings under their tail feathers.

Weekend at Walkersons Weekend at Walkersons

All Cuckoos are brood parasites but they are not the only ones. Honeyguides, Honeybirds, Indigo birds and Whydahs are too. This behaviour is characterised by  the female Cuckoo waiting for the host nesting bird to leave its nest to feed. The Cuckoo lays one egg in the host’s nest. The parasite’s egg is usually similar in colouring to the host bird’s eggs. Critically, the incubation period of the Cuckoo’s egg is shorter than that of its host’s eggs, giving the Cuckoo’s chick an advantage over the host’s chicks. The result is that the host bird normally only rears one chick, the parasitic Cuckoo chick.

I was fortunate enough to see what I think was a Common Cuckoo chick being fed by a female Cape Wagtail.

Weekend at WalkersonsWeekend at Walkersonss

Weekend at Walkersons

Weekend at Walkersons

Most Cuckoos parasitise a number of different host species. Typical host species are robin-chats, shrikes, starlings, babblers, bulbuls, warblers, sunbirds, weavers and wagtails. I find the choice of sunbirds and wagtails surprising given their small size.

Weekend at Walkersons

Weekend at Walkersons

Weekend at Walkersons

Usually the Cuckoo chick has the same colour gape with similar markings as the host bird’s chick. It is this colour match when the outsized chick opens its beak which is thought to induce the host bird to feed the chick.

Weekend at Walkersons.

This little Cape Wagtail female worked endlessly to feed this African Cuckoo chick. The chick called perpetually with its squeaky wheeze. The Cuckoo chick would watch the Wagtail and as soon as she had something in her beak, the Cuckoo chick would fly over to her and demand to be fed.

Weekend at Walkersons

Weekend at Walkersons

Rael and Helene Loon have a very good chapter on brood parasitic behaviour in their book, Birds -The Inside Story.

A Cuckoo is distinctive in flight. It has long and pointed wings and usually flies fast and direct. Cuckoos are generally insectivores so presumably they choose their host on that basis. Being insectivores they usually migrate north during the cold months because of the dearth of insects in southern Africa in winter. This is common among many bee-eaters, swifts and swallows and some Kingfishers and storks.

Only about one percent of birds use brood parasitism as a breeding technique. Using almost no energy to build a nest and raise their chick improves the adult Cuckoo’s survival rate. Some Cuckoos can lay over 20 eggs in a breeding season. The Cuckoo chicks are altricial meaning that must be reared and fed by the parent/host from birth until they are developed enough to feed themselves. I find it incredible that Cuckoos all have their own calls and songs (except the Common Cuckoo which makes almost no sound) despite not being reared by its parent.

Cuckoos do not have it all their own way. Host birds will mob an adult Cuckoo if they see one. Some hosts such as weavers even try to make the entrance to their nests too small for the Cuckoo to get in to lay its egg.

Nature uses only the longest threads to weave her patterns, so each small piece of her fabric reveals the organization of the entire tapestry.

 Richard Feynman

Cuckoos add one extra weave of colour and texture to mother nature’s tapestry. In nature, the more you look the more you find and more you learn.

Seek to understand nature, marvel at its interconnectedness and then let it be.

Have fun

Mike

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