The Great Crested Newt
(Triturus cristatus)

Description

Size

The Great Crested Newt is the largest of the three British species of newt reaching a maximum adult length of 170mm, on average they are at least one and half the size of the smooth newt and nearly twice that of the palmate newt.

Colour

The upper body is dark brownish/black with a warty skin texture. The warts along the sides and top of the legs have white tips which produce a speckled effect. The belly is bright yellowish/orange with a pattern of black blotches. The contrasting colour pattern is extremely striking and is diagnostic and unique to each individual newt like a figure print is to a person. Another distinguishing feature is the toes which are black with yellow/orange stripes.

The Crest

In the breeding season the males develop a jagged crest along the back which, after a break at the rear of the abdomen, re-continues to the end of the tail. It also has a silvery white stripe along the side of the tail. Females tend to be larger than males and in spring are noticeably swollen with eggs. They lack the male's crest and silvery white tail stripe, but instead have a yellow/orange stripe along the bottom of the tail which is present all year.

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Lifecycle

Hibernation

In common with the smaller species of newt, Great Crested Newts typically spend late summer, autumn and winter months on land, hiding in small mammal burrows, crevices in tree roots, or under rock or wood piles. In gardens they seek refuge under patios, rockeries and in old walls. A study carried out in the 19990's found that the average hibernation depth was just 70mm. Reports from people finding colonies of black looking lizards in gardens usually turn out to be Great Crested Newts in hibernation. On damp mild evenings they may emerge from their resting places to forage on land. They prey on a range of invertebrates such as small earthworms, insects, spiders and slugs. They will also feed whilst under refugia.

Breeding

They return to their breeding ponds on nights when temperatures reach 5ºC or more, usually corresponding to the months of March or April but occasionally as early as February during mild weather. They may over-winter in ponds as adults, juveniles or tadpoles; however, they are the least likely of our 3 species of to over-winter in the water. During the day they hide in thick vegetation or in silt at the bottom of the pond, emerging into more open water at night to feed and to perform elaborate courtship displays. This is the best time to watch them with the aid of a torch. Adult newts whilst in the water also feed on a wide variety of prey. In early spring they will take advantage of frog tadpoles. Adults returning to the ponds to breed in late April and May will readily feed on newt tadpoles and frequent cannibalise their own species.

Eggs

Eggs are usually laid from March to May, the numbers laid each night building up as the season progresses, and a mature female may lay up to 200 or eggs by the end of the season. The eggs are laid on the leaves of water plants, which the female carefully folds over to protect the egg. She is also selective about the type of plant chosen. Floating sweet-grass Glyceria fluitans , water forget-me-not Myosotis scorpioides and water mint Mentha aquatica are the most frequently selected plants in the West Midlands . Often many eggs are laid on the same leaf resulting in an easily recognisable concertina effect. The whitish or cream coloured eggs are about 4.5mm in diameter, twice as big as the buff coloured eggs of the two smaller species of newt.

Development

The embryos take up to 3 weeks to hatch and are then about 12mm long. 50% of all Great Crested Newt eggs die at the tail bud stage due to a genetic abnormality, but this factor does not have an adverse influence on Great Crested Newt recruitment. The tadpoles have forward pointing gills and the toes are long and slender. As they grow they develop a deep tail fin with dark spots which tapers to a fine point. They also begin to develop black spots on their flanks and upper surface which as they grow gradually coalesces into the continuous black markings typical of the adult. The head of the tadpole is broadest part of the body and underbelly is silvery. It is at this stage that they have been mistaken for small fish. After about 12 weeks the gills are gradually absorbed and the tadpoles start to gulp air from the surface of the pond.

Lifespan

The tadpoles in the their early developmental stages feed mainly on water fleas and other micro-crustaceans, as they get larger they predate a wide range of aquatic invertebrates including the tadpoles of the other newt species. At the end of their third week they physically change into metamorphs, a smaller version of the adults and leave the water. Metamorph emergence is usually between the months of July and September. Males will return to water to breed after two or 3 years, the females a year later. For their relatively small size they can move great distances over land, usually up to 500m and sometimes up to 1000 metres. They do not necessarily return to the pond where they hatched, so are readily able to colonise new ponds in the vicinity. They are relatively long-lived, averaging 7 to 8 years, the oldest reaching up to 15 years.

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Habitat

Landscapes

Great Crested Newts generally prefer larger, well established ponds with open areas for display and courtship and plenty of weed for shelter, smaller ponds, including garden ponds in the vicinity of ponds with established breeding populations are also colonised. In England and Wales there are landscapes which support many ponds in close proximity Newts will move between ponds within a landscape provided they are within a reachable distance. Landscapes rich in ponds tend to support more robust population of newts because if conditions become unfavourable in one pond, for example if it gets swamped by bulrushes and dries out, they can move to and breed with in an adjoining suitable pond. Where such landscapes exist with lots of ponds supporting Great Crested Newts they are known as meta-populations because of the regular movement of individuals from pond to pond.

Fish

Great Crested Newts will generally avoid ponds with fish. Recent research has indicated that they sniff the air when nearing a pond and avoid ones in which they can smell the presence of fish. Ponds which drawn-down rapidly in summer or even dry up in dry periods are not a problem for newts as periodic desiccation eliminates fish

Suitable sites

The terrestrial habitat is extremely important and a factor that is often under-estimated. Surrounding habitats, as mentioned above, needs to provide foraging and hibernation sites as well as dispersal corridors to other ponds, so features such as scrub, long grass, hedgerows, and piles of logs or stones in the immediate vicinity are important. Large populations will generally only establish where both the aquatic and terrestrial habitats meet biological requirements.

Decline

The decline in Great Crested Newt numbers is attributed to the infilling of ponds and a deterioration of both aquatic and surrounding habitats. Although pond losses have largely halted and new ponds are being constructed many of these are managed as fish ponds, and as fish prey on the newt larvae, they are of little or no value for breeding newts.

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Status & Legal Protection

Great Crested Newts declined significantly throughout most of the 20 th Century largely due to pond losses and habitat destruction. It is the least common of our three species of newt and is the least able to adapt to changes in the landscape. As a consequence of declines in numbers the Great Crested Newt is protected under the European Habitats Directive and is also fully protected under the Wildlife and Countryside Act of 1981 such that it is illegal to intentionally capture, kill, injure, or disturb them in their place of shelter. In addition, Great Crested Newt habitat is also protected. It is thus an offence to damage or destroy their breeding pond or resting place. In order to carry out legitimate surveys for scientific or educational purposes whereby disturbance and handling is necessary, a specific licence is required from English Nature or the appropriate statutory nature conservation agency.

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National and Local Distribution

National

Internationally lowland England and Wales are the main centres of distribution for this species. It is far rarer in occurrence in mainland Europe . However, its distribution across the United Kingdom is somewhat irregular. It is absent from Ireland and Cornwall and rare within Scotland but is locally common within parts of the North Wales, the West Midlands, Cheshire and north-west England . The Herefordshire Ponds & Newts Project revealed that 46% of ponds within the county supported Great Crested Newts. Nationally, this is very high pond occupancy for this species and ranks Herefordshire alongside counties such as Worcestershire, Warwickshire, Cheshire and Gloucestershire , Kent , Sussex and Essex where the Great Crested Newt can be said to be locally common in occurrence . However, it appears to be locally deficient in some parts of county; in particular areas where there are few ponds such as highly intensively managed agricultural land on the Herefordshire Plain

Herefordshire

They are quite able to occur in atypical sites. In Herefordshire Great Crested Newts were found in a large farm reservoir covering of 1.2 ha and over 3m in depth just a few miles to the north of Hereford City . A torchlight survey of the reservoir on 15 th May 2005 revealed 96 adult Great Crested Newts. It had been constructed over two pre-existing ponds which presumably had previously supported breeding populations. Unfortunately the upper reservoir which flows into the bottom now supports carp and stickleback. A newly constructed pool of about 750m 2 metres with a depth of over 2 metres on the edge of the Black Mountains was also found to support Great Crested Newts. Great Crested Newts were also found in three out of five kettle holes surveyed, which are natural pools originated from melting blocks of ice during glacial periods.

The largest of these covers about 2 ha but is semi-permanent. In the floodplain of the River Wye Great Crested Newts commonly co-exist with three-spined stickleback. Five ponds with mature sticklebacks and Great Crested Newt tadpoles have been found. Typically these ponds have good vegetation structure with a good cover of submerged plants and draw down rapidly in summer due to the porous substrate.

Other sites

Great Crested Newts regularly occur in garden ponds in Herefordshire, this is especially where garden ponds are located within 500m of field ponds supporting breeding colonies. A good population was found in a series of lily ponds belonging to a stately home in the Golden Valley . Great Crested Newts also occur in disused sections of the abandoned Gloucester and Hereford Canal . A colony of great created was also found in a school in Hereford City in a square space completely surrounded by buildings measuring just 16 x 10 metres the breeding pond was just 6 metres by 4 metres in length with a butyl liner and permanent water supply.

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