Wednesday, 15 November 2006

Heron drops by

We had a new bird in the garden last week - a grey heron. Although not the most popular of visitors for some, we were delighted to see such an impressive bird. The heron was perched on a wall; stiff and erect, it was alert to any danger but seemed uneasy within such urban surroundings. It must have been attracted by the presence of three ponds, one in each of the neighbouring gardens. At least two of these are free of fish, designed as they are with wildlife in mind, so it seemed unlikely that the heron would find them quite as attractive as they may have appeared from the air. Perhaps sensing this, the heron laboured up into the air after a few minutes to disappear behind neighbouring houses.

Herons have done well in recent years, their numbers increasing thanks to a run of mild winters. Cold winters, leading to frozen waterbodies, can spell disaster for herons, isolating them from their feeding grounds and increasing mortality levels within the population. The influence of winter weather on the heron population has been documented thanks to the British Trust for Ornithology’s annual Heronries Census. The study has been carried out annually since it was launched in 1928 by the late Max Nicholson, making it the longest running study of a bird population in Britain (and possibly the world). Although many heronries contain just a few nests, some can contain dozens or even hundreds. I used to live next door to a small heronry at Wolterton Park, to the north of Aylsham. Each spring, the ekk ekk ekk calls of the young herons could be heard, as they demanded food from their parents. The ground beneath the colony was splattered with droppings and pellets, the latter containing the coughed-up hard remains of unfortunate fish, eels, voles and amphibians.

Nowadays, I tend to see herons on the coastal marshes or along the river valleys well inland but, as my recent sighting shows, they will also visit garden ponds, a habit that can cause consternation for some. Discouraging herons from taking fish is not straightforward. A net covering the entire pond is the only truly effective deterrent.  Plastic herons, sold on the notion that having one by your pond will discourage a “real” heron from visiting, are useless since herons are not territorial and will often feed communally. Intersecting wires, placed a foot or so off the ground around the pond, may work because herons do not like stepping over objects. Of course, you could just add more cover within the pond itself, accept that you may lose the occasional fish, and enjoy the sight of such an impressive bird.

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