ANIMAL ESTATE client 8.9: GREY HERON
FOR ANIMAL ESTATE 8.0: LONDON
SCIENTIFIC NAME: Ardea cinerea
RANGE: They are found all over the UK and in Ireland – apart from mountainous regions of Scotland that lack water reserves. They rarely migrate out of the UK anymore, except in extremely cold weather, or if there is need for better foraging after breeding season. If the heron migrates, it will travel to the Netherlands, France, Spain, and Portugal. Northern European herons are known to fly over to the UK for winter period – some crossing the Sahara Desert.
HABITAT: Ground, wetlands, lakes (particularly the edges and the shallow parts), rivers (especially slow-flowing rivers), swamps, marshes, ponds, parks, high woodland, estuaries, seashores, cliffs, manors/stately homes/castles. Shallow water, garden ponds.
HOME CONSTRUCTION: Reed beds, tall trees. Nests are 3 foot long platforms or cups in trees. Nests are heavy and large (to support up to five babies and the adults). Nests are re-used unless they get blown away.
BUILDING MATERIALS: Sticks, twigs in bushes or trees, rich oak, dense pines.
BUILDING MOTIVATION: Mating, raising young.
THREATS: Human construction (e.g. homes, airports, and other construction). Other birds attack and try to eat them in hardy times. In 1950s it was thought that herons would not breed in London again - only better quality water in the city has encouraged them back. Herons need sufficient numbers of their potential prey in order to survive – mainly fish.
INTERESTING FACTS:
One in every 30 or 40 herons are in London.
You can see them all year round.
In 1949, Richard Fitter the naturalist said, ‘It can be asserted with a fair degree of certainty that neither the heron nor the spoonbill will ever again breed in London.’
In 2003, Regents Park held a Heron Weekend to celebrate the bird - the royal park had the largest colony of herons in the capital. In 2007, herons were thriving at a record 32 pairs in Battersea park.
They are very tame birds.
They are silent birds unless in flight or in nesting colony, where they will make a ‘kaark’ cry and a variety of other calls.
Herons fly slowly with their legs trailing behind. They can circle so high that they get mistaken for birds of prey.
Herons stab their prey (frogs, fish, young birds, small mammals such as voles, and amphibians) with their long thin sword-like bill, and swallow it whole. They can be spotted in fields seeking out prey such as rodents.
Their crests become ruffled and breast plumage agitated when intruders are nearby.
Male herons fly about wildly and offer female herons a stick when they anticipate mating. Once the female is accepted, there are ‘greetings displays’. Their bills and legs are brighter in colour during mating season.
Heron babies are considered ugly. Young herons grow within a matter of days to adult-size and cannot be told apart from their parents. Older herons strut with their feathers raised to protect their territories.
Colonies can be between 25 and 40 metres off the ground.
Herons are becoming very bold as predators for food - they like meat and fish scraps and will even queue for food. One of the top predators in the freshwater food chain, the heron eats a variety of fish, frogs and birds which helps to keep their numbers down.
Most herons stay for the winter but some fly out to other parts of Europe, such as France, Spain and Portugal. There are 14,200 nests in Europe.
The oldest known heronry in UK is near Chilham in Kent, and dates back to 1280AD. The longest running bird survey in Britain is the heronry census - 1928.
One individual heron was known to survive for 35 years.
RESOURCES:
Londonist
BBC
Royal Parks
RSPB
Brittanica
Wildlife Whisperer
Books and internet sources used as research: Birds, Reader’s Digest Wild Britain, The Reader’s Digest Association Ltd, 2007; Garden Birds, Reader’s Digest Wild Britain, The Reader’s Digest Association Ltd, 2008
COMPILED BY: Fliss Collier