The Miracle of Frog Travel!
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First Spawn of the Year
Am I the first to see any frogs and spawn this year? I was out on Saturday, March 2, in Harrogate’s Valley gardens and there they were, three frogs and a small batch of spawn, brilliant. Actually, I wasn’t really the first because I was drawn to them by the strange behaviour of a lady who seemed to be staring intently at the water. Soon afterwards she was joined by a strange man (me) staring equally intently at the water. Equally strangely the frogs had not chosen their usual place just above the boating pool but were ‘cavorting’ in the stream between the Pump Room entrance and the café. Maybe passion got to them before they reached the usual spawning grounds, although running, smelly, water seems a pretty poor option. Anyway I can’t believe that I am the first (second?) this year to see them, have you seen any already?
New to Britain, the Pool Frog
We have in this country six native amphibians: the common frog, common toad, natterjack toad and smooth, palmate and great-crested newts. Well we did have, but now we apparently have seven because the pool frog has been recognised as a UK native. It seems that over the years pool frogs from southern and central Europe have been introduced into Britain and its status was considered to be just that of an introduced species. Well, a number of folk have researched this and a combination of genetic, sound, archival and archaeological investigations have discovered that fossil evidence from around 1,000 years ago, coupled with the similarity of our pool frogs with Scandinavian pool frogs for which there exist no historical records of introductions from that part of the world, means we have a new species. Pool frogs were presumed extinct in the wild in 1995, but have since been reintroduced at a single site in East Anglia, so don’t expect to go out and see any locally; however, similar frogs were heard calling in Yorkshire in the 1980s and these have expanded their range since 1997 and mainly along the valley of the River Hull, including Tophill Low, a great wildlife area owned by Yorkshire Water (small admission charge). In fact we now have 19 sub-populations in our county. Lancashire only have one (The Naturalised Animals of Britain and Ireland – Christopher Lever, New Holland, 2009). This new species apparently leaves its breeding until May or June and produces similar clumps of spawn to common frogs with eggs that are brown above and yellowish underneath. They can also be seen basking in the sun regardless of how hot it is. So there you go, some pointers to look out for in case you think you have seen pool frogs. The pool frog has full protection under UK law. It is an offence to kill, injure, capture or disturb them, and to damage or destroy pool frog habitats. It is also illegal to sell or trade pool frogs. This law applies to all life stages (source Amphibian and Reptile Conservation).
Just to complicate the frog situation even further, there has been introduction of other frogs to this country including the European green tree frog, although these have probably died out because really we are too far north for them to survive. A much more frightening introduction was the American bullfrog which was first introduced in 1959, often introduced inadvertently with imported goldfish. I say frightening because their diet included small birds, voles, young mink, ducklings and fish. Fortunately it seems that all introductions have been eradicated. This bullfrog is however a different species to that which has caused such havoc in Australia. Another frog introduction worthy of mention is the marsh frog, introduced in 1934-35, an introduction which resulted in folk near where they were introduced complaining to their MP because they were so excessively noisy. I always enjoy the sound frogs make and consider it calming, although I have never heard marsh frogs. It seems that marsh frogs are considered the most successful alien amphibian introduction and they have become established in some parts of the UK, but nowhere local. Other frogs introduced, and apparently these are very similar to the pool frog, include the edible, southern marsh or Iberian water and Italian pool frog. I suspect for most of us we needn’t worry too much about what frogs we see as they are almost certainly the common frog, Rana temporaria.