Steve's Herpetological Blog

An insight into the life of Steve, his research and the many books he reads

#SciFri

#SciFri: What’s that beeping in my garden?

Picture this. You’ve been sitting in your garden during lockdown or the recent warm spell. Marvellous! Whilst turning the page to the book your reading or taking a sip of wine, you hear a conspicuous beeping sound. At first thought you think nothing of it but then you realise it’s coming from inside your garden. You’re confused because it sounds like an electronic beep, like a smoke alarm with a dying battery or a New Age car alarm. What you don’t realise is that you’ve just heard a male midwife toad or two. There is a recording of some males below for you to listen to, just be sure to turn it up.

This is a group of males calling, each one makes a beeping sound once every second or so which soon becomes a chorus depending how many males are present

Midwife toads are a non-native species found throughout Great Britain, with the first population being founded in Bedford around the turn of the 20th Century. Since then, these toads have been moved around and other unrelated populations have also sprung up. Our investigations have found that midwife toads are far more widespread than we originally believed. The toads themselves are a grey-olive colour and grow to 5 cm in length. The males carry strings of eggs around their hind legs (pictured below) which is how this species gets it’s name. Curiously these toads breed and live exclusively on land, they only need small amounts of standing water when they’re a tadpole. As adults they are very secretive and tend to hide under paving slabs or within garden rockeries. You’re most likely to hear them on damp and warm night and you may even find some individuals wandering the garden.

A male from the Cambridge population carrying a string of eggs

Midwife toads can be differentiated from common toads by their smaller size, smaller paratoid glands behind the eyes, lack of affinity to water and greyer colour. Common toads are also gregarious, breeding explosively in the spring (as pictured below) and after their tadpoles metamorphose in the late spring/early summer there is the potential for confusion. However common toad metamorphs are miniature versions of the adults although some may be darker in colour. If you get close enough, midwife toads have vertical pupils whereas common toads have round pupils. Midwife toads are unlikely to be seen so don’t worry if you can only hear them, they are extremely elusive at the best of times.

A group of common toads at a breeding pond

If you do think you’ve got midwife toads in your garden please get in touch by using the Contact page. I’m part of a team running a national monitoring project of midwife toads in the UK, investigating both their distribution and their origins. If you’d like to know more about the project, you can read our updates here. Every extra dot on the map and DNA sample we can gather will help in aiding to put this puzzle together. Please record any amphibians or reptiles you find in your garden here.

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