To catch a cuckoo

It was a chilly start to the morning. For the first time in a while the temperature reading was 3° and next to the time of 4 am once again it was a bit of an urgggh moment getting up. This time dense mist hung low, the tops of the trees poking out and reaching into a clear sky above, fading from black through midnight blue to pale blue pink as dawn slowly broke.

Arriving at the grassland heath, bounded by forest and farmland, the dawn chorus was in full swing. Skylarks, garden warblers, yellowhammers, even a turtle dove calling from somewhere in the mist beyond. The occasional tall tree and low grassy humps of what were once, many many years ago, stump rows appear out of the mist like ghost ships. Movement ahead reveals the equally ghostly forms of small sheep, the maintenance team of this grassy heath.

The grass is wet, its tops drooping under the weight of water, as we make our way over to where a tree stands alone. Here a large mesh net is set up surrounding the tree and within the centre a speaker placed. The aim? To catch a cuckoo.

With the speaker on the unmistakable call of a cuckoo booms out through the mist, followed by a bubbling sound that many may not recognise but is the call of a female. We have barely retreated, when the responses start and one then two males start calling in response. A little further away and a real female bubbles also. Out of the mist and over our heads a male makes for the tree and the speaker; perching ceremoniously on the top of our pole! The slim grey body, long tail, white chest with barring and pointed wings resembles a small bird of prey. This is of course on purpose. For cuckoo’s do not worry themselves with rearing their chicks, leaving this for other birds like reed warblers and meadow pipits who in return develop ways of recognising the cuckoo and its eggs. What has developed is an evolutionary arms race. While host birds need to keep a watchful eye for cuckoos, they also need to worry about predators like sparrowhawks that rather than parasitizing their nests are looking for a meal. The cuckoo takes advantage. By looking like a sparrowhawk it causes birds to leave the nest area for that little bit longer, giving the female time (all 10 seconds of it) to lay her egg without being mobbed.

Misty morning... spot the cuckoo

As our percher disappears from the top of the pole, a second bird comes swooping overhead and low in towards the tree, finding its path ultimately stopped by our net which with its large mesh holds onto the bird safely.

Cuckoo in the net

And that my friends is how you catch a cuckoo! (Of course you have to have a ringing licence with a mist net and tape lure endorsement). Up close he is stunning, grey-blue, and perfect barring across a pale chest, bright yellow bill and eye.  And for this guy not only is a unique metal ring added to his leg, a satellite tag is strapped on with a specially designed harness. For cuckoos (and this seems to be a recurring theme for our wildlife) are in decline and we have lost over half of our breeding birds in the last 25 years. But the picture is more complicated than that. In some areas cuckoos are doing better than in other areas, in England for example the decline is greater.

What a beautiful bird!

This is where this satellite tagging project run by the BTO, and championed of course by the BBCs Spring Watch, comes into play. Already the data is showing interesting results with the suggestion of different migration routes and the indication that weather conditions across their range have a significant impact on survival.

Where will this cuckoo go? Which route will it take? How will it fair over the next few weeks, during its migration south, overwinter and hopefully on its return? With its satellite tag will have the answers to all of these questions... soon….