Amphibians
Common frog (Rana temporaria)

A tailless amphibian with a smooth skin which tends to jump rather than walk. The pupil of the eye is horizontal ovoid, its dorsal surface (back) and flanks are very variable in colour - yellowish brown or brown but can also be olive green and some individuals can also be black, reddish or golden.

The back of the frog can also be spotted and/or striped. The ventral surface (belly) is normally dirty white or pale yellow speakled with grey or brown (male) females tend to have pale yellow to orange bellies.

The most consistent markings are the dark patch behind the eye and the strong barring on the hind limbs.

Length: 6 - 9 cm

 

Common frog Rana temporaria

Breeding and Spawn

Emerging from hibernation in late February spawning usually takes place in early March. Though occasionally the frogs will emerge sooner and spawn as early as January.

The females are ready to spawn immediately after hibernation and the animals enter into amplexus very soon after arriving at their breeding ponds.

The spawn is laid in clumps and typically consists of 300 - 400 gelatinous eggs containing black embryos with a white spot.

The very young tadpoles are black but soon become speckled brown in colouration making them distinguishable from the permanently black tadpoles of the common toad.

Text Source RAUK Forum Idenfification http://www.herpetofauna.co.uk/common_frog.htm

 
Common toad (Bufo bufo)

Tailless amphibian. Warty Skin.

Distinct bulges on back of head, known as the parotoid glands

Tends to walk not jump

Covered in obvious warts

Horizontal slit pupil yellow/golden brown iris

Dorsal surface and flanks, fairly uniform brown/greenish grey

May appear light sandy brown in warm weather

Ventral surface, dirty white/cream with speckles

Some colour variation occurs and individuals have been recorded with brick red spots.

Length: males up to 8 cm females up to13 cm

 

Toads crossing road in Little Leighs, Chelmsford

Sexing

Males have dark nuptial pads on three inner fingers that are very noticeable in the breeding season. Females are generally larger than males.

The spawn of the common toad is easily distinguished from that of the common frog as it is laid in strings not clumps. Closer examination shows that the spawn string contains a double row of eggs. Toadlets metamorphose in June and July.

Breeding and Spawn

Common Toads emerge from hibernation in late February and start a hazardous journey to their breeding ponds. Many toads are killed, as they attempt to cross busy roads. Toads return to the same pond year after year. Males clasp the females in a special hold known as "Amplexus" during mating. They remain like this for a few days as the female lays her spawn.

The male Common Toad has a loud release call that he will use if he is grasped by another male. This sound is the most commonly heard from breeding toads, though the males will croak occasionally to attract a mate.

Text source RAUK http://www.herpetofauna.co.uk/common_toad.htm

 
Palmate Newt (Lissotriton helveticus)

Tailed Amphibian-Smooth velvety skin

Dorsal surface and flanks, Females - yellowish to olive brown, with dark freckling.

Males - Olive brown, spotted and marbled with darker colours which may fuse to form two lines along the back

Ventral surface, uniform creamy yellow or orange occasionally some brown spotting on the belly.

The throat is pure white or pinkish and rarely spotted.

Dark stripe passing through the eye on either side of the head

Length: The smallest of our native newts, 7-11 cm, in some populations the adults only reach 6.5 cm.

Sexing

Males are smaller than females and tend to have larger spots on the upper body, during the breeding season they develop a low, straight-edged crest on the back and a more developed crest on the tail. The male has a distinct filament at the end of the tail during this time and black "frills" on the hind feet. The females may have a very plump appearance in the aquatic stage due to un-deposited eggs.

Eggs

The female deposits her eggs individually on aquatic plants, carefully wrapping each egg in a leaf. It is impossible to distinguish the eggs of the Palmate Newt from those of the Smooth Newt in the field. The adults remain in the pond until July, the young newts or "efts" leave the pond during August/September.

Text source RAUK http://www.herpetofauna.co.uk/palmate_newt.asp

 
North American Bullfrog (Lithobates catesbeianus)

This is a very large aquatic frog distinguishable from the introduced European species by lack of dorsal lateral fold, a very large eardrum and the vocal sac being beneath the chin rather than at the side of the head.

The large eardrum and lack of a dorso lateral fold (see Common Frog for comparison) helps to distinguish this species from the superficially similar though smaller, water Frogs such as the marsh, edible and pool frog that have been introduced to some areas and of course the smaller common frog.

Tends to be more uniform in colour than native and other introduced species, usually green, olive-green or brown on the dorsal surface and flanks, the males tend to have a yellow throat during the breeding season.

The ventral surface (belly) is normally whitish, mottled or spotted with grey. The adult frogs can grow up up to 20 cm in length while the tadpoles can grow up to 15 cm at metamorphosis which can take over three years to complete. The species has a distinctive mating call which sounds like a cow hence the name the 'Bull'frog

Bullfrog tadpole - found in Essex 2006

UK Distribution

Breeding has occurred in the past at the Sussex/Kent border - from the mid 1990's to the present an eradication programme has removed this population. A second population has been detected in the East of England since 2006 the population has since been removed. A further population has been found in the South East and efforts are now being taken to remove this population and determine whether any other populations are known from the UK.

Status

Exotic - The American Bullfrog is a voracious predator and a potential threat to British wildlife. Tadpoles of the American Bullfrog were at one time widely sold in garden centres, imports are now banned due to the risk of this invasive species establishing in the UK. Vigilance is still required as there have been reports of accidental introductions of tadpoles included with consignments of aquatic plants.

Release of exotic species into the wild is a criminal offence under the Wildlife and Countryside Act 1981.

This includes introduction of exotic or alien species that may already have become established.

The interpretation of "wild" in the act includes private gardens from which escape is possible.

Text Source RAUK http://www.herpetofauna.co.uk/bullfrog.htm