Birdwatcing: The Heron

The heron is up before daybreak to use every opportunity in the hunt for food

IN THE early hours of the morning on the River Dee in Aberdeen a silent stalker can sometimes be seen on the banks, hunting for fish in the shallows. It might still be dark with the full light of dawn an hour or two away, but this grey heron is a resourceful bird and it is using the orange glow from the nearby streetlights to aid its quest for fish.

Its feet move with exaggerated caution with head and body tilted forward, careful not to cause a ripple or splash that may disturb a feeding trout or salmon smolt. The heron stops, it stares intently into the dark choppy waters and then – like the unleashing of a coiled spring – the long sharp bill quickly stabs downwards to grab a wriggling fish, which is then nimbly juggled in the air before being swallowed head first.

I often used to witness herons hunting in such a manner on the River Dee just upstream of the Victoria Bridge near Torry in Aberdeen and had assumed fishing during darkness was an unusual piece of localised behaviour, given that the heron is widely regarded as a diurnal bird.

However, I recently saw a heron behaving in exactly the same way in a burn lined with street lamps that runs through the village where I now live on the edge of the Ochils in central Scotland. It would seem that the heron is an adaptable bird, quick to exploit any feeding opportunity that comes its way, and it wouldn't surprise me if it utilised the soft white illumination of the full moon for nocturnal forays in areas away from our towns and villages.

Such opportunistic behaviour was further illustrated last autumn when I watched a heron at the weir on my local river which had quickly cottoned on to the fact that salmon trying to negotiate its tumbling rapids provided an excellent chance for an easy meal. The heron would hang around the weir edge waiting for a small salmon to come within striking distance, although usually the fish were tantalisingly out of reach.

The heron is one of our largest and most distinctive birds, but always very shy and quick to take flight at the approach of a person. Such wariness perhaps stems from the persecution it once suffered from fishery managers concerned about salmon and trout, although today it is a protected bird that thrives in many parts of Scotland.

For such a large bird it is a very secretive breeder, usually nesting in small colonies of six to ten pairs with the bulky nests well hidden in the tops of high conifers. The ground beneath the nests can often give an insight into the feeding habits, with it not being unusual to find the remains of dropped fish. I once found a flounder under one such colony in south-east Scotland several miles from the coast, which highlights the large distances birds travel in search of food.

Frogs form an important part of the diet in the spring and it is thought that egg laying is timed so as to coincide with the abundance of spawning amphibians, providing a bounty of food at a crucial time.

Herons may also occasionally take mice, voles and large insects such as dragonflies. The seashore on the west coast is a good place to see herons hunting for rockpool fish at low tide.

Unsurprisingly, given its stature and prominence, the heron is a bird that features widely in folklore. It was said that a heron's foot exudes a scent that is attractive to fish and fishermen would carry a heron's foot in their pockets to try and boost catches. But the most engaging tale is surely the delightful image conjured by the long-held belief that a heron's nest has two holes in the bottom to allow the long legs to dangle through when it is incubating eggs.