Since posting the original version of this blog we have been back to the colony and found two males carrying eggs in their late stages of development. I have added a couple of new photos towards the end of the blog.
The Midwife Toad, Alytes obstetricans, gets its English and scientific names from its breeding method, in which males carry strings of eggs around their hind limbs. Its natural distribution covers much of western Europe but several colonies have become naturalised in England. One of these is in a small village on the South Yorkshire – Nottinghamshire border, quite close to where I live.
The toads there live in stone walls, using small chinks in the stonework to hide during the day and emerging at night to call, feed and breed. A small group – reportedly five toads and about a dozen tadpoles – were apparently brought to the area in 1947 and released into a private garden. They seemed to disappear and the colony was forgotten about until the 1980s, when they were found again, by which time they had spread throughout part of the village. Though rarely seen, they are often heard making their soft but persist “ooo ooo ooo” calls in the evening as it gets dark.
I was fortunate to be taken to the colony by a local resident recently and, though the conditions seemed too cold for amphibians, they started to tune up as dusk fell and by the time it was completely dark the full concert was under way. Calls could be heard from every direction, far and near. Around the same time we started to see individuals emerging from their daytime hideaways and before the night was over we had found eleven, including adults, sub-adults and juveniles.
Taxonomic note: midwife toads belong to the family Alytidae, which also contains the painted frogs. The are five midwife toad species, all in the genus Alytes. One of them, A. muletensis, occurs on the island of Mallorca and was only discovered in the 1970s, and another, A. maurus, lives in Morocco. Two of the remaining three species, A. cisternasii and A. dickhilleni, occur only on the Iberian Peninsula while the remaining species, A. obstetricans, known as the Common Midwife Toad, has a wide distribution over western Europe. This species has been divided into several subspecies, differences between them being slight (as, indeed, are the differences between the full species). Identification of species and subspecies is made much simpler if their origin is known although there are areas where the ranges of the Common Midwife toad and the Iberian Midwife Toad overlap.
It is assumed that the English colonies originate from the nominate form, A. obstetricans obstetricans, which occurs naturally in France and neighbouring countries.