Flanders Moss NNR
The Flanders Moss cuckoos are starting to quieten down. The bog is a hive of cuckoo activity through the breeding season and an important site for this iconic species locally. Last week there was a bit of cuckoo activity with 3 in the same tree at once (see picture above – 2 can be seen) and there was still one calling on Monday but usually by the end of June they won’t have as much to say for themselves. That is understandable because their pairing activity is timed to peak with the host birds in whose nests they lay eggs in. On Flanders this is most probably meadow pipits. Most meadow pipits are feeding their chicks now so it is too late for a cuckoo to lay its eggs in those nests but this nest is one I found last Friday and it still has eggs.
The mating system that cuckoos use is not well understood but it seems that the males have overlapping song ranges and females have overlapping egg ranges so there is likely to be a bit of mix and match going on!
Also with cuckoos, mating can be instigated by the male or the female and then once the female is ready to lay she starts scoping out potential nests sites. She does this by sitting and spying meadows pipits behaviour and also moving around and gauging how agitated the birds get to her presence. In this way she can pin point a nest and then she will remove any host birds eggs and then lay hers in the nest. The meadow pipits might lay some of their own eggs but once the cuckoo chick hatches out it disposes of these so that it gets all of the food itself. The nest below is a meadow pipits nest on Flanders that has been found by a female cuckoo, The bottom left egg is paler and bigger but is a pretty good match to the meadow pipits eggs so you can see why the meadow pipits take it as their own. These cuckoos have an amazing lifestyle!