Diamonds in the Dirt

Great crested newts are significantly larger than the small smooth newt, here two females can be seen side by side.

In some of Britain's ponds there lies an almost mythical creature, a creature who's name is known to many, yet few have ever actually seen it. A shy, retiring, nocturnal creature which is right up there with Britain's most iconic species. This is the great crested newt an absolute giant when compared with our other newts, the smooth newt and palmate newt. In fact great crested are so much larger, that the two smaller species occasionally become a light snack. Great crested newts are our most striking amphibian, a large black (or dark brown/green) salamander like newt, with a bright orange/yellow marked underside. The male has a well developed crest and bright flash along the centre of the tail (during the breeding season). Female crested newts occasionally reach 16cm making them just about our largest native amphibian.

A male (bottom) and female (top) during their terrestrial phase, not the pale line on the males tail. The female has a orange/yellow base to the tail which the male lacks. 

Britain supports a significant proportion of the European population, making it an important stronghold for the species. This leads to one of the reasons for the species notoriety as it is protected by European law (as well as British). The species has quite specific habitat requirements and is less of a pioneer in comparison to common frog and smooth newt. The preference for large-medium, mature, moderately  vegetated, ponds, with open lecking areas and a reasonable depth with no fish, means populations can quickly stop producing if these factors change or such ponds are lost. Hence why the species like most of our amphibians have declined over the past century, but perhaps at the most rapid rate than any of the other species of reptile or amphibian and a further reason for its high level of protection.

The underside of a female crested newt, showing the orange/yellow tail base and markings of the belly and throat. Each marking on the underside is unique to the animal like a finger print. 

Great crested newts are typically a lowland species (although I did curiously find one in a small valley in raised moorland a number of years ago) which occupies hard, circumneutral water. As mentioned the species have a clear preference for large mature ,well vegetated ponds which do not contain fish, especially where these exist in clusters and meta-populations (a group of interlinked populations) can exist. If one pond is lost the meta-population remains in the area. Terrestrial habitat is also important where it surrounds ponds and links ponds together with a preference for hedgerows, woodland, scrub and rough grassland. As woodland progresses to climax and has more fallen deadwood it generally becomes better. These newts are perhaps our most aquatic amphibian species but when on land occupy voids between tree roots, rotten stumps, disused small mammal burrows, rubble piles and similar habitats with dry, frost free, tight gaps in which they can squeeze themselves (they like to be secure).

By their 1st spring juvenile great crested newts are almost the same size as smooth newts. 

Like our other amphibians great crested newts hibernate over the winter and generally start to return to ponds from as early as February. A catalyst of damp nights above 5^oC tends to spark migration to the breeding pond (most adults hibernate within 500 metres of this). Males tend to arrive at ponds slightly earlier than females, a pond I looked at last night had about 90% of males out of 35 individuals, possibly as a result of this. Crested newts are far more nocturnal than our other amphibians and also tend to be more benthic (bottom dwelling) and are only occasionally seen during the day, which probably results in so few people seeing them. They tend to leave the pond over a protracted period between May and September, with males often leaving first.  

Great crested newts are also known as warty newts due to their rough skin. 

Breeding courtship is an elaborate activity, with a lot of tail waggling and dancing, which ultimately results in external fertilisation. Once fertilized the female lays between 250-300 eggs individually within aquatic vegetation, carefully folding each egg. Favoured egg laying plants include water-forget-me-not (about the best plant for these newts), water cress, water speedwell, floating sweet grass, water mint and great willowherb. Interestingly due to a genetic defect (development arrest syndrome) about 50% off all eggs in every population abort around the early "tailbud" stage. It remains a evolutionary mystery as to why a species has evolved such a wasteful means of reproduction.

A water forget-me-not showing a typical great crested newt egg fold (centre of the picture). 

As mentioned earlier adult smooth newts are periodically taken, however the diet largely consists of water bugs, beetles, leeches, worms and tadpoles. Terrestrial prey is similar and as a generalist almost any invertebrate (or vertebrate) which fits in the mouth is eaten. Great crested newts use both vision and electric impulses to locate their prey. Foraging usually occurs during the night, when few predators are around.

I am a licensed great crested newt ecologist and all photographs were therefore taken legally. It is an offence to disturb, catch or handle, this species unless it is in immediate danger, without a Natural England license. All photos taken with a compact camera whilst working. Like many of the YETI posts it is a quick overview and I will try to revisit this species and take a more detailed look at its ecology.