Springtime, frogs, and happiness

What better on the spring equinox than to stop by a frorgy?

Wednesday 20th March was the vernal (spring) equinox, marking the start of astronomical spring. It was also World Frog Day, and International Day of Happiness, although I didn’t know about these until after I’d been on my mini adventure to the woods. It couldn’t have been more perfectly timed.

I don’t know a single person who dislikes spring. How could anybody not feel good about longer days, warmer sun, the dawn chorus and fifty shades of green bursting into the world? Spring is when colour returns to the pale cheeks of a dormant world. And it’s magical.

In my little patch in Oxford, spring has been ramping up for several weeks and I’ve ticked off a few of my favourite ‘firsts’ of the year: primrose (January 11th), hazel flower (January 27th), brimstone butterfly (February 15th), chiffchaff (March 16th), wood anemone (March 16th). There are plenty of treats still to come: next month, the woods will be transformed by bluebells and snake’s-head fritillaries will flower. Cuckoos, swallows and swifts (oh yes!) will return, and thoughts will turn to summer.

One of the things I have been eagerly awaiting happens at the CS Lewis Nature Reserve, just outside Oxford’s ring road on the northeast side. This three hectare woodland used to belong to celebrated author CS Lewis: he is said to have enjoyed wandering here while writing his famous Narnia series, including The Lion, the Witch and the Wardrobe. The steeply sloping wood of beech, oak, birch, alder, ash and hawthorn is dotted with large boulders called ‘sandstone doggers’ and right now it is full of feisty little birds. Yes I’m still here, they shout; no Gary, this is my patch; NO I DON’T THINK SO, JIMMY. I slip my way through the greasy mud below, a lot more grateful for my walking boots now than on the bike ride over. A great-spotted woodpecker is drumming close by, adding a low tone to the chorus of great and blue tits, song thrush and wren. The melodies of robin and blackbird combine with the noisy staccato ‘wipwipwipwipwip’ of a nuthatch. Jackdaws ‘tchak’ overhead.

At the bottom of the hill the wood opens out to a large pond, and it is here that I am heading. Turning the corner around the pond’s first curve, I stop because there is a little toad on the path. This is a good sign of what’s to come.

The sky has brightened since I left the house, and enough sun is coming through the high cloud to create reflections and glimmer on the pond’s surface. But I can see well enough to know that there are dozens of frogs and toads in the water. And I can hear well enough to recognise that they make a lot of noise. I first thought that I was hearing ducks or moorhens calling, but the more I watched the bustle of activity going on in the pond, the more connected the noises became to them.

When frogs and toads breed, the eggs aren’t fertilised internally, unlike in mammals and birds. Instead, the female releases her eggs directly into the water and the male must fertilise them there and then. This creates a lot of competition between males, who all want to father as many offspring as possible, so to maximise their chances of securing paternity the males leave nothing to chance. This is why they piggyback onto the larger females from the very first opportunity, sometimes ambushing them and hitching a lift as they make their way back to the breeding pond.

Holding on for dear life. The smaller male on top grips the female in what is called amplexus.

This tight mating grip is called amplexus, and achieving it is a good first step, but a male is still not guaranteed fatherhood at this stage. He needs to hang on until the female starts laying her eggs - if he can then he gets to be first to release sperm on them, and therefore has the highest chance of fathering the tadpoles. What makes his life harder is the fact that there are many other males all vying to achieve the exact same thing, jostling for position and desperately trying to dislodge the current frontrunner. And that is what is going on right in front of me with the toads. It’s fascinating to watch, especially with the soundtrack of quiet, but high-pitched ‘qwark qwark qwark’ sounds.

There are other noises too: low, farting croaks, which jostle for attention in the melee of toad squawks and birdsong; less frequent but just as insistent. It’s hard to pinpoint the source of the sounds while trying to take in the big picture of all these busy, wriggling little bodies. Better to spend some time focusing on an individual or two, that’s how you get a feel for what they’re doing and why.

The mass of frogspawn in the pond indicates that peak frog mating has already happened, and this explains why I’m mainly seeing (and hearing) toads. Toads tend to congregate at their ancestral breeding ponds a couple of weeks after the frogs, though there’s definitely overlap. In peak frog breeding times there would be a chorus of croaks for three to seven days, the calls functioning to attract a female and compete against other males. The croak comes from the male’s throat pouch, which he inflates to produce the sound. You can see it in this video, when the frog in amplexus is jostled by a competitor.

The amphibians I’m seeing are common frogs, Rana temporaria, and common toads, Bufo bufo. These are the typical frogs and toads that we see in this country and also the most boringly named. Even the Latin name Bufo just means ‘toad’. So this is the toad toad; the most toady of all toads. Our other, much rarer, species are the pool frog and natterjack toad, both of which have suffered dramatic population declines and are now restricted to just a handful of sites. It’s fair to say that I’m not an expert on these animals, meaning that I was today years old when I learned that all toads are technically frogs. There are clear differences between the two groups, of course: toads are squatter, with dry, warty skin, and they crawl rather than hop. Frogs tend to stay in water because their skin is more susceptible to drying out, while toads can venture further away and often live out of water until it’s time to breed. Toads have poison glands behind their eyes, while frogs don’t. And when it comes to their spawn, frogs produce those classic clusters, while toads produce long strings which are wrapped around pond vegetation. Nonetheless, evolutionarily speaking, toads are a subgroup of frogs, since they belong to a group called the Anurans. In popular usage, however, toad is used to refer to any frog with dry warty skin and short legs.

I’d already seen frogspawn this year, more than a month ago. But what I hadn’t seen was the spectacle of all of these animals coming together to mate. Three weeks ago, my partner and I had walked up here to check on the status of breeding. I was expecting to see some activity but there was nothing. Not a single frog to be seen and no spawn. It was a surprise, until I thought to check on previous years. The benefit of being a natural ‘recorder’ is that all of this information is available in my photo library. Last year the frorgy was in full swing on March 21st, while in 2021 it was March 23rd. Which suggests that the toads and frogs born in the CS Lewis Nature Reserve have a pretty consistent internal calendar. Driven by ancient impulses to return every year, they are a wonderfully predictable harbinger of spring. I’ve no idea how many animals breed here each year, or whether there have been some changes in the timing of breeding over a longer period, but this reserve is one of the best places around Oxford to spot frogs and toads.

It was only later that I spotted posts about World Frog Day on social media. And then about International Day of Happiness. What a good coincidence! Because when I got home I was reinvigorated. The sight and sounds of all those toads and frogs; the brimstone butterflies chasing each other down the path; the birdsong and the sun on my face. Spring has well and truly started - the frogs say so.

General information

• https://www.arc-trust.org/common-toad

• https://www.wildlifetrusts.org/wildlife-explorer/amphibians/common-toad

• https://www.froglife.org/info-advice/amphibians-and-reptiles/common-frog-2/

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Facts of the fortnight

• Which land-based large carnivore do you think was responsible for the most attacks on people between 1950 and 2019? Lion? Tiger? Grizzly bear? No, no and no. A recent publication found that 1337 of the 5440 attacks during this period were committed by the sloth bear, a species that is native to the Indian subcontinent.

• Just in - it’s good news from Scotland, where Parliament have overwhelmingly voted in the Wildlife Management & Muirburn Bill. This introduces licensing for grouse moors, wildlife traps and muirburn, as well as banning snares. It came on the same day that another satellite-tagged hen harrier went missing in suspicious circumstances, so is a huge win for conservationists.

• I didn’t think I’d still be providing updates, but Charlotte the stingray has still not given birth! She was due about a month ago, but given her unconventional pregnancy (parthenogenesis), nobody really knows what to expect. She’s had a recent ultrasound which confirms that her pups are still alive, and she now has her own Amazon wishlist, including bloodworms, multivitamins and filter pumps.

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#NaturePhotoADay

If you follow me on Instagram, you’ll see that late on New Year’s Day I decided to set myself the challenge of starting a nature related Project365 (this year, #Project366), meaning I have committed to sharing one nature photo every day for the whole of 2024. You can follow along on Instagram if you like, but I share my favourite from the previous fortnight here anyway.

As always, there have been too many lovely things over the past fortnight to easily choose one. But I’m going to go for for these larch flowers, which we found as we were walking around the woods last weekend. These are the female flowers which will develop into the cones, and they’re a really beautiful colour. I’d never seen them before so it felt like finding treasure!

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