While taking my coffee into the garden on a sunny if cool May morning, and listening to the birdsong, it occurred to me that one bird I was not hearing was the cuckoo. The sound of the year’s first cuckoo used to be the subject of competitive letters in the national newspapers, though none that I could remember recently.

Many Royal Society correspondents took a great interest in such features of the natural world – for example, William Cole, who wrote to Robert Southwell in 1693 about a cuckoo’s egg in a sparrow’s nest. In November 1738, a letter from a Mr Cox describes his observations of cuckoos, discussing their characteristic marks and stating that ‘They sleep all the winter, and in summer, feed upon insects young birds and eggs.’ Cox refers to earlier reports by the naturalist John Ray, who had described cuckoos as ‘very indolent … and will not make their own nests, nor hatch their young’; Cox proceeds to observe that ‘the species is preserved because they suck wagtails eggs. And lay their own in the same place, so that the wagtail considers them its own and feeds them … when they are arrived to their full degree of magnitude, they eat up the old wagtails, and fly away’.

I love this assertion by Mr Cox – with no proof provided – that these are facts, because he has seen cuckoos in a cage fed by a wagtail, and that the servants of a local landowner would seek them, and always found them ‘in wagtails nests and nowhere else’. Cox’s account was considered interesting enough to be worth recording in the Register Book in 1738, but it does not appear to have been published in the Society’s Philosophical Transactions.


Illustration by Henry Jenner of a young cuckoo being fed, from his brother Edward’s paper ‘Observations on the natural history of the cuckoo’, Royal Society L&P/IX/80.


The major article on cuckoos was written by Edward Jenner, who is better known for his researches into vaccination and smallpox than for natural history. Jenner was a pupil of the surgeon John Hunter, who encouraged Jenner to produce an article, ‘Observations on the natural history of the Cuckoo’, which was read to the Society on 13 March 1788. This was a much more scientific article, based on proper observations and referring also to those of another Fellow, Daines Barrington, the barrister, antiquarian and natural historian.

Jenner describes the first appearance of the cuckoo in Gloucestershire on 17 April, and notes how its song is well known, though that of the female ‘is most peculiar’ and resembles the call of a ‘dab chick’. He lists its habits, and the many small birds’ nests into which the cuckoo puts its eggs, including the hedge sparrow, the ‘water wagtail’, the yellowhammer and the whinchat. Jenner’s observations run to 41 handwritten pages, and were considered of sufficient quality to be published in the Philosophical Transactions.

The peculiarities of the cuckoo have always fascinated researchers, none more so recently than Nicholas Davies FRS, who was interviewed on Radio 4 on his current extensive research on how parasitism by cuckoos and rejection behaviour by hosts co-evolve. He is our Croonian Lecturer, and will be presenting his research findings at the Royal Society on 14 May.


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