The Botanic Garden, a waterbird favourite and tracking down the butcher of Comberton

The Botanic Garden is well worth visiting at any time of the year, and even now in the cold of winter it is still rewarding.

Snowdrops and aconites are in full flower and in the winter garden the fiery shoots of dogwood blaze in the sunshine. This spectacular variety, Cornus sanguinea or ‘Midwinter Fire’, has yellow stems topped in bright orange-red, and is now at its best.

After a recent overnight frost, much of the main lake had a thin layer of ice with just a few areas where the water had been kept open, partly by the activity of the mallards, the drakes now in splendid breeding plumage.

One of my favourite waterbirds is the little grebe and a pair usually nests each year at the edge of the lake. These tiny birds spend most of their time swimming or resting on the water, occasionally diving for small fish and other aquatic prey.

The air was still cold, but the sun took some of the chill away as I watched a little grebe behaving rather strangely.

Between each dive to feed below the surface, on bobbing back up it would position itself precisely, with its rear facing directly into the low sun.

I raised my hand to cover it with shadow and it immediately shifted into the sun, adopting the exact same posture with the fluffy feathers around its tail fanned out into a flat circle and the skin partly exposed. I assume this heats the grebe’s body in what is a neat form of thermoregulation.

On checking the literature, I later found a couple of scientific articles in which this behaviour is described, not just in little grebes, but also in other small grebe species, especially those living on lakes in cold regions.

I find there is always something new to learn from studying nature, especially if you watch quietly and observe with care. Certainly, I had never imagined a waterbird would warm itself up by using its bottom as a solar panel. The scientific name Tachybaptus ruficollis translates as ‘red-necked quick-diver’, which sums up this bird well, as does its common name of dabchick.

There were not too many visitors that day so I hoped to spot a kingfisher, but I couldn’t see one around the lake.

Then as we walked alongside the stream that feeds the lake from Hobson’s Brook, we spotted one perched close to the water where it had found an ice-free hunting site.

The wary bird soon spotted us and zoomed off towards the brook beyond the trees.

Every so often, usually in autumn or winter, a particular rare and elusive bird makes an appearance in the countryside, and I have lost count of the times I have tried in vain to see it. So, when I heard that one had been spotted nearby, I decided to try again, but without much hope of success, having long since decided that this was a species I was fated never to encounter, at least not in Britain.

We duly found ourselves, armed with binoculars, trudging along a lane near Comberton, then gazing across an open field towards a distant hedge. There, at the very top of a small tree sat a medium-sized bird with quite a long tail, silhouetted so we could see no colour, but unmistakably the species we had come to find.

The great grey shrike then flew off behind a nearby wood, but we followed it in the hope of getting a better view. We joined a small party of fellow birdwatchers, some equipped with impressive long-lensed cameras, and tracked down the shrike which was now much closer and in better light so we could clearly see its essential features.

It seemed untroubled by us and obligingly moved even nearer, setting off clicks and whirrs from the cameras. The great grey is the largest European shrike and is a splendid bird with a hooked bill and striking grey, black, and white plumage.

Shrikes are known as butcherbirds for their occasional habit of storing prey by pinning them on thorns. After years of failure, I had finally struck lucky with my bogey bird – the butcher of Comberton!

Martin Walters is a Cambridge-based writer and naturalist

Read more on Martin Walters’ author page

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