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.