Herons are a familiar sight in many of The Royal Parks. Hunched over and watchful from amongst lakeside willows, slowly stalking prey through reeds or with their lumbering flight and harsh call, they provide an impressive spectacle for visitors. A priority for nature conservation in London, Regent’s Park supports one of London’s most important heronries.
There have been herons visiting Regent’s Park since the early 1930’s, with the first pair recorded as breeding in 1968 on what is now called Heron Island. Against a backdrop of slowly increasing heron populations in London, possibly helped by general improvements in water quality, in the park the birds initially nested in three large elm trees and a horse chestnut tree on the island, and the population steadily grew. Tragically, the elms were infected by Dutch Elm disease and had to be felled on health and safety grounds, as this disease wiped out elm trees across the country in the 1970’s.
We were concerned that this would cause the birds to move away from the park. Fortunately, the population was maintained. The herons continued to breed in the remaining horse chestnut tree on the island, where they still nest today.
A helping hand
We also made an effort to encourage the herons to also use nearby Bandstand Island, to increase the resilience of the population. Our initial attempts to create artificial nest platforms used bundles of pea sticks and wooden pallets, before we joined forces with a willow weaving company to create a more robust nest structure. Out of the first batch of six installed, four were used successfully with chicks raised for six years until the willow nests fell apart.
Unlike today, the herons in the Royal Parks used to be very shy and only used the park for breeding. With few suitable habitats in the park for them to hunt for fish and amphibians, the herons would instead forage further afield, as they do in the wild, flying to The Thames and other suitable stretches of water. In London they will also visit people's gardens, and soon learnt that their neighbours in London Zoo were very generous with their fish – although we suspect the penguins, pelicans, flamingos and sea lions did not have much choice in the matter!
Improvements for nature
We have introduced a wide range of other measures to improve the park for wildlife, including herons. In particular, the creation of reedbeds, introduction of meadow areas and creation of shallow pools and ponds has provided more opportunities for amphibians (and other wildlife), providing additional food for herons. This has also provided opportunities for visitors to enjoy this noble species, although there is concern that the feeding of herons is doing them more harm than good – reducing their hunting activity and changing their diet - so please don’t be tempted to feed them.
Herons in the UK do not tend to migrate unless there are long periods of severe winter weather. These conditions seem to be a thing of the past, and with continued improvements in water quality the UK population has steadily increased, with the Regent’s Park heronry reaching a maximum of around 28 pairs. Herons will lay eggs from as early as December, whilst the last young can still be on nests late in September. It is believed that some pairs may lay a second clutch of eggs, but it is also likely that birds who were unable to occupy a nest in early spring wait until a nest vacancy appears later in the year. This makes confirming the annual nesting count challenging!
The willow trees on the lake edge are very popular for nesting these days. The branches are very pliable and light, making it easy for herons to carry them and weave them into their nests. They will add material to the nest throughout the breeding season, keeping the nest as clean as possible by burying branches which are covered in droppings and rotten food.
The herons also must contend with other wildlife to protect their nest sites. For example, the relative newcomer the Egyptian goose will happily use an abandoned nest given the chance, with the predation of heron eggs and conflict between birds observed.
This year the first eggs were laid in mid-January and even though they had to contend with wet weather and strong winds the colony is doing well. At the end of March, 17 nests were occupied: 15 nests on Heron Island and two on the western end of the Bandstand Island.
We will continue to keep a close eye on the herons of Regent’s Park. They made the most of the quiet conditions in the park during the lockdown, continuing to build their nests, raise young and forage through the park. Before long they'll be nesting again, with some herons laying eggs as early as February.