The Cuckoo. Cuculus canorus.

The cuckoo belongs to the Family Cuculidae and the Order Cuculiformes. The common cuckoo is placed in the genus canorus from the Latin canere meaning to sing.

The well known vernal call note of this species is generally heard first in the south of England in about the second week of April. If the weather is affording a cold snap or in any other way bleak, even if the birds have arrived, their call note is seldom repeated.

The call is thought to be, at all times, affected by the weather. According to the British Cyclopedia of Natural History 1853-37 which states--" During a long continuanceof drought it {the call" becomes more and more hoarse, till at length it seems to be uttered with considerable effort and the first syllable of it is broken in to two or three. But no sooner does the wind veer to a rainy quarter, than before even a change is visible in the sky, it immediately softens and is pronounced quite melodiously and distinct."

The note is repeated either when the bird is perched or as it flies across a field, sometimes also during the night.

                                " In April come he will,

                                  In May he sings all day,

                                  In June , he changes his tune,

                                  In July off he will fly,

                                  but in August -go he must"

The above words, and many variants of it, summarise the cuckoo's stay with us here in Britain.

The cuckoo-image taken in Bhutan

Courtesy of Dr Raju Kasambe  CC BY-SA 4.0 License

Description of the cuckoo C.canorus.

Adult birds are uniform grey above and on throat, they are barred below. Male also has a grey breast. White spots on wing and tail. Juveniles may be grey or reddish brown, both are barred all over. There is a pale spot on the nape of the neck.

In relation to the size of its body the wings are medium long, the neck medium short, the bill which is short is thick with a yellow base, legs are short or very short.

The flight of the cuckoo is direct, when in flight the tail is often wedge-shaped with white spots showing. from below pale bands can be seen on the under wings, the tips are dark. Hops on the floor.

Cuckoos can be mistaken for birds of prey, especially the male sparrow hawk, however, the wings of the cuckoo are long and pointed and the tail is graduated. The bill is not hooked. They have likewise been mistaken for the kestrel, stock dove and collared dove especially at a distance. The cuckoo tends to hold its head up whilst in flight.

They measure 33cm {13+ inches} in length. The wingspan 58cm {19 inches}  The male weighs 130g the female 110g.

Breeding and eggs.

Cuckoos are summer visitors to our shores and when they arrive they have but two things on their mind. One is feeding and the other is breeding. Once mating has occurred the female seeks out the nests of small birds. this may occur on bushy moorland and heaths, in woods, on well wooded farmland and around reed beds.

Meadow pipits are a favourite nursery of the cuckoo. The female may be observed loitering with intent, seeking out some unattended nest to deposit her egg in. Other favoured species is the dunnock**, sedge warbler, pied wagtail, robin** and skylark**.

In Britain the eggs are rarely coloured like those eggs of the foster parent. Two cuckoo eggs may be encountered in the same nest, however, this is thought to be due to two separate females.because the cuckoo does not build a nest, she does not have to undertake the laborious task of incubation  her eggs thus she can afford to lay many more eggs than normally be the case for a bird of her size. This may be as many as 25 eggs per season however, 9-10 seems to be the average number.

The cuckoo egg is remarkably small for the size of the bird, hardly bigger than those laid by the much smaller skylark. But when one considers the size of the nests in which they are deposited they are much more proportionate. They are usually oval in form of a reddish white colour, thickly sprinkled or blotched with reddish brown spots, which, are rather more numerous at the large end, like other eggs it is subject to variation.

Once the young have hatched in 11-13 days, the chick will thrust out its nest mates to perish. the curious hollow in the cuckoo chicks back seems designed for such an operation, which fills in within a couple of weeks of the operation being completed. according to the British Cyclopedia of Natural History {1835-37},  the cuckoo seems to lay her egg into the first suitable nest she happens to locate. Whatever the species of bird is, for example a seed eater, or as the cuckoo herself an insectivore species. the book states--" It is one of the most curious facts of natural history, that many smaller finches, which never themselves touch any sort of insect food, and even their own young exclusively on softened vegetable food ejected from their own craws, will notwithstanding, rear up the young cuckoo upon caterpillars and other insects"

The young cuckoo remains in the nest for 17-21 days and the foster parents has to persevere with some tedious labour to fulfil the chicks increasing demand for food. In the latter stages of its nest bound days the baby cuckoo is often much larger than the foster parent providing the food for it.

Big job for a small foster mother

Photograph courtesy of Per Harald Olsen via Ravenloft  CC BY-SA 3.0 License.

Even after fledging the foster parent will follow the cuckoo and continue feeding it. When they are capable of feeding themselves they tend to eat large hairy caterpillars, often poisonous species,which they seem to eat with impunity, while other species of birds leave these well alone.

Whilst feeding on a tree the cuckoo leans well forward upon the bough on which it is sitting, as it examines the foliage for caterpillars, its tail being generally raised, and it frequently takes considerable leaps from bough to bough, considering the shortness of its legs.

Cuckoos leave on their remarkable journey to Africa without ever knowing who their  parents are. Click on Cuckoos Blog 2011 and Cuckoos Blog 2012 in the content banners on the right hand side of this page for a remarkable insight into this journey.


Courtesy of Vogelartinfo  GFDL 1.2 License.

Conservation issues--Source BTO

In the UK the cuckoo is on the Red List of Conservation concern, and as such is a Priority  species subject to a species action plan {SAP} under the auspice of the UK Biodiversity Action Plan {BAP}.

In the years 1996-2001 the cuckoo was on the Green list of conservation concern indicating there were no concerns at that time.

In the years 2002-2007 the cuckoo had been added to the Amber list indicating that there had been a decline in population numbers/distribution of between 25-50% .

2012-- the cuckoo, because of declines in population/distribution numbers of over 50% the bird was added to the Red list of conservation concern.

In England the long term trend is a rapid decline. Scottish and Welsh populations appear to be stable. In Europe including the Republic of Ireland they are not a species of conservation concern.

The Irish name for the bird is cuach and a good area to see/hear them is Connemara. 

There is an estimated 14,000 pairs in Britain during the summer.


Cuckoo in flight.

Courtesy of Vogelartinfo GFDL 1.2 license

Reuse of images. 

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UK Conservation status 2021

UK-Red list of conservation concern. Due to declines in population/distribtution.


RED because Recent Breeding Population Decline (1981-2010), Recent Winter Population Decline (1981-2010), Recent Breeding Range Decline (1981-2010), Recent Winter Range Decline (1981-2010) 
 Past Assessments2009-2014 RED  2002-2007 AMBER  1996-2001 GREEN 

 Europe-Species of least concern.

Courtesy of the BTO. 

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Birds of the world -11 Cuckoos of the genus Clamator.



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