identification of frogs & toads (anurans) in the uk four native species likely to find two...

Identification of Frogs & Toads(Anurans) in the UK

• Four native species

• likely to find two

• Several introduced species

• becoming more common!

Native Frogs & Toads

• Common frog• Common toad• …also spawn and tadpoles• Natterjack toad (specialized habitat)• Pool frog (restricted distribution)

Alien Frogs & Toads

• “Green” (water) frogs (including pool frogs)• Midwife toad• Clawed frog• American bullfrog• Other “escapes” including fire-bellied toads

Report aliens at www.alienencounters.org.uk

Common frog

Frogs have smooth skins and are relatively athletic, for example leaping about if netted

Dark patch usually present behind eye (includes eardrum)

Common frogs: variable coloration and markings

Common toadToads have rough, warty skins and walk or “hop” rather than leap about

Female

Male

Dark markingson or near gland,eardrum notvisible

Males: less robust and a shallower head but with chunky “Popeye” arms

Common toad (male)

Spawn

• Frogspawn is always found in clumps• Toadspawn is deposited in long gelatinous strings wound around water plants. It is usually produced a little after frogspawn. It is harder to spot but may be revealed during netting

Frog and toad tadpoles

• On hatching, tadpoles of both species are very dark and look similar• Frog tadpoles become mottled and look greyish or brown but toad tadpoles remain black

Tadpoles: behavioural differences

Toad tadpoles often aggregate or shoal whereas frog tadpoles are secretive, hiding amongst plants or mud

Metamorphs

Rare Species

Natterjack: found in dunes and heathland, mostly south and northwest coasts

Pool frog (native): reintroduced to a small area of East Anglia

Aliens: green or water frogs

• Most likely non-native species (pool, marsh & edible frogs)

• Most likely in South-east England

• Very variable in colour, bask and call from around ponds

• Obvious, paired vocal sacs either side of head

Other Aliens

< 15 cm or more!

Clawed frog

American bullfrog

Photographs

• Photographs used in this presentation are by Chris Gleed-Owen, Fred Holmes, Phyl King, Hanna Powell and John Wilkinson

• Copyright of all photographs remains with the photographers and ARC

• These photographs should not be used for purposes other than NARRS training without the permission of the photographers.