I have spent the last 3 summers monitoring cuckoos and their reed warbler hosts at Wicken Fen Nature Reserve, guided by the vast wisdom of Nick Davies: a master cuckoo whisperer. What an immense privilege it has been to learn about this fascinating system and landscape first-hand! If you also want to immerse yourself in the intricacies of life as a cuckoo on Wicken fen, then read Nick's exquisite book 'Cuckoo: cheating by nature'. To see the fen and it's inhabitants through Nick's eyes is to unlock a secret world. And this little world has firmly etched a place in my heart.
When I first started out on this project, it was a massive sensory adjustment for me to be surrounded by water and lush greenery after 6 years of Kalahari desert and red dust. I can't help but identify with the reed warblers and cuckoos who excitedly sing with the arrival of spring, and then pack up in search of Africa before the autumn seeps in. Late September every year I experience my own 'Zugunruhe', and dream about filling a backpack for African migration. But in summertime, I have begun to feel quite at home amongst the reeds.
This season's cuckoo highlights have been....
Watching a reed warbler build a nest insulated with sheep's wool and then discovering that a cuckoo had been watching too! She certainly laid her egg in the cosiest of nests that was available in mid-May. I thought to myself, that's where I'd put my egg if I had one! But of course, cuckoos lay lots of eggs, so not all of the nests that she used were so superb.
Observing the fascinating deimatic behaviour of cuckoo chicks. Cuckoos remain dependent in the nest for much longer than the reed warbler's own young. Presumably the reed warbler nestlings leave as soon as they can in order to avoid predation, since the longer they spend in one spot and the bigger and noisier they get, the greater the risk of being discovered and eaten. The cuckoo takes longer to fledge and uses a different strategy - any predator approaching the nest by this stage will presumably be as surprised as I am to see a flash of flame red and a lunging, snapping mouth, rearing up out of the nest! It definitely doesn't evoke the impression of a delicious baby bird.
As this season draws to a close, although slightly weary and worn from fieldwork, I am already missing the sneaky cuckoos and the gentle reed warblers. The ephemeral nature of this habitat makes it feel as though it might have all been a dream - one day a peacock butterfly can be feeding on lush blossoms as swifts scream above, but soon enough the same scene might feature only the rustle of dry yellow reeds and a sullen sky.
Even though there will be no chance of cuckoos, the pink skies and starling murmurations will entice me to return to visit the fen over the winter. Or perhaps because absence truly makes the heart grow fonder, I will simply visit the winter fens to mourn the summer, with regret for any day that I took for granted amidst the hustle and bustle of busy data collection.
behaviour and evolution