Wilden Marsh herons are getting ready for their breeding season now: starts in February and ends in June. There are a few herons at the heronry already, waiting for females to arrive.
The grey heron flies slowly with its long neck retracted (S-shaped). This is a characteristic of herons and bitterns, distinguishing them from storks, cranes, and spoonbills, which extend their necks. It flies with slow wing-beats and sometimes glides for short distances. It soars, circling to considerable heights, but not as often as the stork. In spring, and occasionally in autumn, birds may soar high above the heronry and chase one another, undertake aerial manoeuvres and swooping towards the ground. The birds often perch in trees, but spend much time on the ground, striding about or standing still for long periods with an upright stance, often on a single leg.
Herons eat fish, amphibians, small mammals, and take insects in shallow water with the their long bill. I’ve seen dead pike floating in North Pond, each with the characteristic stab wound in the head from the heron’s bill. It has also been observed catching and killing juvenile birds such as ducklings, and occasionally taking birds of water rail size. It may stand motionless in the shallows, or on a rock or sandbank beside the water, waiting for prey to come within striking distance. Alternatively, it moves slowly and stealthily through the water with its body less upright than when at rest and its neck curved in an “S”. It is able to straighten its neck and strike with its bill very quickly.
Small fish are swallowed head first. Larger prey and eels are carried to the river or pond bank, where they are subdued by being beaten on the ground or stabbed by the bill. They are then swallowed, or have hunks of flesh torn off. For prey such as small mammals and birds or ducklings, the prey is held by the neck and either drowned, suffocated, or killed by having its neck snapped with the heron’s beak, before being swallowed whole. The bird regurgitates pellets of indigestible material such as fur, bones and the chitinous remains of insects. Toads are eaten by turning the body inside out, to avoid ingesting its unpalatable skin. The main periods of hunting are around dawn and dusk, but it is also active at other times of day. At night it roosts in trees, where it is often gregarious.
The oldest recorded heron lived for 23 years, but the average life expectancy in the wild is about 5 years. Only about a third of juveniles survive into their second year, many falling victim to predation.