Great Crested Newt (GCN) Surveys
Why might I need a GCN survey?
Great crested newts (GCN) and their habitats are fully protected under UK law. So, if your site or the surrounding area contains potential breeding sites, then you may need a newt survey before site works can begin.
The easiest way to gain expert advice is to get in touch – we’re always happy to discuss your site and provide free advice without obligation.
What types of newts exist in the UK?
There are three native species of newt in the UK: smooth or common newt, palmate newt and great crested newt. Smooth and palmate newts are typically 10cm in length, are often brown to dark green in colour and can be difficult to tell apart.
Great crested newts are much bigger, up to 17cm in length, and black in colour with a warty appearance to the skin. The males develop a jagged crest along the back and tail during the breeding season. Breeding male smooth newts also develop a crest and they are often mistaken for great crested newts. Recently, introduced species have appeared in the UK with the Alpine newt being the most common. These are a similar size to the smooth newt but are darker in colour with an almost scaly appearance to the skin.
Why do I need a licence?
It is an offence to carry out works within an area where great crested newts are present without a licence and is likely to result in the prosecution of the developer. This is the case for all development whether or not it requires planning permission.
Of the three native newt species, only the great crested newt has full protection under UK law, including the places it inhabits (i.e. aquatic breeding habitat as well as terrestrial habitat). Smooth and palmate newts have protection only from being bought or sold.
Where are great crested newts found?
Great crested newts are a lowland species found throughout Britain being most common within central and southern England but are rare in central and west Wales, Scotland and Cornwall. They are absent in Ireland.
Being amphibians they require both aquatic and terrestrial habitats. Breeding sites tend to be small to medium sized ponds with submerged plants for egg laying and more open water areas for courtship display. They tend to prefer ponds that are unshaded on the southern margin, they are not too fussy about water quality but tend not to be found in ponds where fish or water fowl are present.
They also use ditches and canals for breeding but do not breed in flowing water. Adult great crested newts spend a majority of the year away from water. Being largely nocturnal they need a daytime refuge for instance under logs, stones or in mammal burrows and so areas of rough tussocky grassland, scrub or woodland are favoured. Such habitats also provide good foraging potential as they emerge after night fall.
Hibernation requires similar features to daytime refuge and so over winter great crested newts can be found in wood piles, under stones and underground in mammal burrows or in hollow tree roots.
What happens during a GCN survey?
GCN surveys often start with a Habitat Suitability Index (HSI) assessment. HSI is a daytime assessment, with the methodology devised to evaluate the suitability of the pond habitats for GCN. HSI is not a substitute for GCN surveys, as on its own it cannot be used to state whether the pond definitely does or does not support GCN, but it is a useful tool when scoping survey requirements.
It is important that waterbodies surrounding the site are also assessed as newts can be found up to 500m from their breeding pond (or further, if suitable breeding waterbodies are present in the landscape). HSI surveys can be carried out at any time of year but they are best done in the spring or summer.
If any waterbodies are considered to have the potential to be a breeding habitat, then a number of exploratory survey methods are usually employed which look for direct evidence that great crested newts are present.
eDNA is a daytime survey that can be carried out by a GCN-licensed ecologist between 15 April and 30 June (inclusive). The ecologists collect water samples from the pond which are then subsequently analysed in a laboratory. The eDNA test confirms the presence or absence of GCN. If GCN presence is confirmed, follow up survey work is required to determine the GCN population size.
If the HSI results/eDNA survey indicate that follow up survey work is required, the following further techniques are available to GCN-licensed surveyors to confirm GCN presence and determine the population size.
Bottle traps (made from 2 litre water bottles and bamboo sticks) are placed in the water around the pond edges (density of c. 1 bottle every 2m). The bottles must be carefully secured, taking care not to damage aquatic vegetation. The bottles are left in the water overnight and the newts are recorded and released in the morning.
Guidelines on suitable weather conditions and animal welfare must be strictly adhered to in order not to kill or injure newts (and other wildlife).
Surveyors check submerged vegetation for newt eggs, looking for leaves with sharp folds, created when the female lays the egg and folds the leaf (using her hind legs) to protect the egg. Care must be taken not to trample vegetation, and as soon as the first GCN egg is found, the egg search stops. GCN eggs are easily identifiable as they are larger than palmate or smooth newt eggs and white/cream in colour, rather than buff/grey.
In ponds with little or no vegetation, or heavy duckweed cover that affects visibility during torching, the surveyors can create artificial egg laying material by attaching strips of bin bag to a bamboo stick which is then submerged and secured in the pond.
Surveyors slowly walk the pond perimeter after dark and check the waterbody margins for newts by using a strong torch. This survey technique is only used if the pond is relatively free of weeds and not turbid, as this would affect visibility.
Netting can also be used to capture GCN by using a net with a long handle, taking care not to injure GCN. Netting is usually used to indicate presence/ absence rather than for population size surveys, but can be a useful substitute for torching.
Terrestrial searches should not be used on their own to determine absence of GCN, but can be used in conjunction with surveys of aquatic habitat if suitable habitat is present on site. The surveyor checks GCN resting places such as stones, wood, and discarded items such as cardboard boxes, furniture, carpet etc).
Refugia used for reptile surveys can also be used to create additional habitat that can be searched during the aquatic surveys.
Newt Survey Frequently Asked Questions
Our survey calendar will help you to ensure that GCN surveys are scheduled as part of your project planning.