The cuckoo

To hear the first cuckoo of the year is one of the most celebrated of all natural phenomena and this unusual bird has developed a deserved place in our culture and folklore.

The familiar ‘cuck-oo’ or ‘cuck-cuck-oo’ sound is made only by the male bird.  Should you hear a delightful bubbling response to the male’s call then you have heard a female cuckoo.

It is the cuckoo’s habit of laying eggs in the nests of other birds that has attracted a great deal of interest. The female cuckoo has the ability to lay eggs at a rate of up to one per day, for 25 days, in the nests of different birds. 

Across Europe cuckoos have been observed using one hundred different species of host, in Britain there have been at least fifty, and the most frequently used are: reed warbler, sedge warbler, dunnock, robin, meadow pipit and pied wagtail. 

Individual cuckoos tend to choose nests of just one species and their eggs have evolved to resemble those of their hosts. 

The poorest match, in terms of the egg colour, between the cuckoo and its host is that of the dunnock, the most likely species to be used in gardens. It is thought that this might be due to the dunnock being a recent target of the cuckoo and that evolution has yet to develop this match.

The cuckoo’s name was obviously derived from its call, but what is unusual is that its name has been adopted into the English language in such a wide variety of forms. The word ‘cuckold’ came about because the female lays her egg in the nest of another bird so that she has the time to enjoy herself with other males! 

The word ‘cuckoo’ is itself a term of derision and refers to the male cuckoo being taken in by the female’s actions.

Many spring flowers have been named after the cuckoo because they appear at the same time as the cuckoo returns from Africa. The cuckoo pint (Arum maculatum) and cuckoo flower (Cardamine pratensis) are two examples. 

In the insect world, the froghopper’s larva creates a bubbly mixture to conceal itself which has become known as 'cuckoo spit'.

Cuckoos can be found in a wide range of habitats but their population has been declining dramatically in recent years. In order to learn more about the migration of cuckoos the British Trust for Ornithology (BTO) caught five cuckoos last summer and put small satellite transmitters on them. All five of them made it safely to their wintering grounds but at the time of writing only two had made it back to Britain.

The BTO hope to extend this tagging system to include some Scottish birds this year and since the Scottish population is faring better we might learn why. 

To see more about the progress of these cuckoos visit:  www.bto.org/science/migration/tracking-studies/cuckoo-tracking