May 2014
One of the scientific tasks that Vivien and I do each year is to participate in the National Breeding Bird Survey. To do this we survey a single kilometre square that has been randomly allocated to us by the local section of the British Trust for Ornithology. Our square is just SE of Ringmer. The survey involves getting up at 05:00 hrs. on a bright calm morning and walking 2 transects of the square. This is done twice, once in the early part of the breeding season usually during early April, and again in the later weeks, usually in June. We did our early visit yesterday (12th April). We were delighted to hear our first cuckoo, whitethroat and lesser whitethroats. Each of these had flown all the way from Africa to sing to us that morning, and we did appreciate it.
Cuckoos specialise in feeding on hairy caterpillars, well I suppose something has to. They can lay up to twenty-five eggs, each one in the nests of other birds. Each cuckoo tends to be a specialist at using a host species of a particular type, for example robin, dunnock, meadow pipit and wren, but around 100 different host species can be used.
When the laying of eggs is over, all adult cuckoos fly back to Africa again, usually by July. Apparently, cuckoos are rather promiscuous, and will mate with any cuckoo of the opposite gender that they encounter. To do that, the male sings its famous cuckoo song to attract a female, or the female makes a kind of bubbly call to attract a male. After they mate, the female has to go off to find the nest of its chosen host and lay just one egg in it. She then goes off to mate again and find another nest until she has no more eggs left. The adults then fly back to Africa, leaving their young to be raised by their chosen host.
The thing I find amazing is that the baby cuckoos never meet their parents. However, they still know what calls to make when they return the next year, and more amazing still, know that they have to fly back to Africa, and not only that, but they know the way!
A plant that flowers at about the time the cuckoos arrive is the beautiful pink/purple cuckoo flower, also known as ladies smock and milkmaids. This year has been particularly good for this plant with a particularly good showing on the Little Horsted roundabout on the A22/A26 intersection on the Uckfield Bypass.