This seems like an appropriate way to reflect the imminent onset of spring. The awakening of frogs from hibernation and appearance of spawn in ponds and slow-moving streams are classic indicators of the changing season. It typically occurs during February, continuing into March with a three week cycle before tadpoles hatch. Shadier and partially reed-filled ponds are especially favoured by larger assemblies of the breeding amphibians.

I have long had a partiality for frogs, a non-bird or insect wildlife group I especially enjoyed recording abroad during my pre-Covid ramblings of the previous decade. So when Ewan featured a mass mating at a site in Oxford on his own blog (see here) a year ago I resolved to experience the spectacle for myself this season. And after pictures appeared on another Oxon wildlife blog a few days ago I went to take a look this morning.

I will admit that my previous experience of the humble British Common Frog (Rana temporaria) is largely confined to those that occur in my garden each year, typically leaping out to startle me from one hidden place or another in late summer and autumn. Since I do not live close to flowing or standing water I must assume these are immatures that have dispersed from hatching sites such as I visited today. Now I have gained a much fuller understanding of our ubiquitous national frog.

Frogs mostly hibernate on land, finding underground places of concealment or secreting themselves in surface structures or piles of vegetation. Unlike mammals that pass winter in deep sleep, amphibians assume a period of low metabolic function and so may be active intermittently. Some males risk lying dormant or leading a slow-moving existence in larger ponds or those with an inflow, where potentially fatal freezing over is less likely. Hence they will be in place when the first new season females arrive. There they are joined by the large scale nocturnal migration of adult frogs that is prompted by rising temperatures as each spring approaches.

One such breeding site is Lye Valley LNR (see here) in Headington, north-east Oxford (SP547058). The wildlife-rich SSSI (pictured above) lies between the Churchill Hospital complex to the north-west and a mid-20th century housing estate on its other side. This is one of the best national examples of very rare “calcareous fen” habitat, a wet alkaline area fed by lime-rich natural springs along the valley walls. Owned by Oxford City Council, it is wonderfully well maintained in partnership with BBOWT and volunteer groups, with a boardwalk running the length of the site to facilitate access.

I arrived there in the late morning today having arranged to meet Ewan on-site. The breeding frog pools (above left) lie in the central stretch of the valley and just two more observers were present. My first comment was “No frogs”, but one of the others then spotted movement. Getting my eye in I became aware of masses of frogspawn in the pool we overlooked. Ewan was next to arrive and things soon livened up as presumably the water temperature rose. Before long we counted around 20 adult Common Frog all active amongst reedy habitat in the centre of the pond, the males commencing to sing in chorus.

My immediate impressions were how much larger these were than the frogs I am used to seeing in my garden, and also the different colour forms. According to Collins field guide adults may be up to 11cm in length. Some of the biggest females today seemed quite bloated, presumably with spawn and often with more than one male in attendance. Females are stouter in build than males, being shorter in the body and longer in the legs. The hind legs in both genders are one and a half times the length of the head and body combined, as shown in the bottom row studies below.

These images from today match the illustration in Collins. Breeding males appeared grey-toned with a bluish throat, while the larger, plump females are reddish brown with pearly white warts on their flanks. But the ground colour of the Common Frog is actually very variable. The upper parts may be grey, olive, yellow, brown, orange or red; and this may be speckled, spotted or marbled with brown, red or black. The variably speckled underparts are dirty-white to pale yellow in males and yellow to orange in females. In the breeding season males’ skin becomes slimier and the warty granules on females’ skin enlarge.

My research further reveals there is a marked tendency for individuals’ colouring to alter from light to dark according to the surroundings, as the pigment cells of the skin can expand and contract in response to varying intensities of reflected light. I have included all this detail here as the immature Common Frogs of my previous experience had always appeared pretty much alike to me, but not so in adults so it seems.

There is no courtship ritual. Males in a breeding pond will clasp competitively the nearest female around the body and lie on her back in an embrace known as “amplexus”. The females then shed one or two clumps of spawn which is fertilised by the coupled male, though in the above picture things appear to be the other way round. Unmated males will also inject sperm into the proceedings to help things along. The most prolific females can produce up to 4500 eggs, deposited over vegetation in shallow water and often forming a continuous floating carpet with the spawn of other females.

My experience today was much like butterflying in any publicised location, in that finding something means other people will home in and restrict my picture taking space. It being a sunny Saturday morning we were soon surrounded by mums and kids, the young children taking a keen interest in the “froggies” and displaying an encouraging wildlife awareness. All Covid restrictions were lifted in Great Britain a few days previously, which is something I agree with and welcome, but the situation in this next picture still seemed strange.

One lady and her daughter then walked away and I noticed them stop and point into the next pond, so taking the opportunity for a bit more elbow space I followed. I had checked that one not long previously but now it’s surface had suddenly erupted with many more partially submerged frogs (pictured below) than the first pond contained. To my untrained eye these looked smaller than that 20-strong group in what I suppose might be the “master pond”. And all the while the dull, rasping “grook … grook … grook” male chorus filled the air, augmented by the atmospheric grunts and chirps of the females.

After spawning such mass assemblies of Common Frog disperse into the countryside, or in this case suburban Oxford possibly for up to several kilometres. As I now realise, individuals take three years to fully mature and may live for up to ten years. The species occurs almost everywhere in the British Isles, and western Europe other than the Iberian peninsula, Italy and the Balkans; typically inhabiting damp places and undergrowth. I had not witnessed their breeding spectacle before and so was pleased to have done so now.

This annual event here today appeared to be common knowledge amongst local people. Leaving the site in the early afternoon I was passed in the opposite direction by children carrying pond dipping nets. The public is asked not to remove frogspawn, since the alternate location to which it is transferred may not suit and doing so can spread disease affecting other wildlife. Visitors to Lye Valley LNR are also requested to keep to the boardwalk and not enter the sensitive and unique habitat of this beguiling urban oasis.

This seemed worth doing. As in 2021 my year’s opening national and WestPal bird list addition is a Nearctic vagrant. Then it was a White-throated Sparrow in early April (see here). This time, on checking the distance it was only 126miles, so a sunny Friday forecast was enough to tempt me out. I’ve not been inactive during the interval since the previous item herein, having dipped the Somerset Baikal Teal in January then connected with the nearby Penduline Tits. Other than that it’s been mostly local birding, which several notable sightings including Pallas’s Warbler aside does not fall within this journal’s remit.

This lifer is of course not a Robin at all, but a species of Thrush. The misnomer is said to have arisen from early settlers in north America welcoming the comforting sight of a red-breasted bird and relating it with the favourite from back home. Though a rare vagrant to Europe this is actually the most numerous bird (c370 million) across the US and Canada, where it frequents gardens, parks, open farmland and woodland edges. It resembles familiar British Thrushes such as Blackbird and Fieldfare in shape, behaviour, jizz and calls.

The Eastbourne bird, either the 25th, 29th (or is it 33rd?) British record was first reported three days previously on Tuesday 8th but is said to have been present for rather longer. As the first twitchabIe one since 2010 it is proving to be very popular. I arrived on-site around midday, after a three hour drive despite the modest distance, and parked in the residential cul-de-sac cited on RBA as soon as I saw birders up ahead. Then, on going to investigate, I came upon a 50-plus crowd (pictured below) that included several familiar faces.

I was approached at once by Adam (Gnome), who had been expecting me since we usually seem to meet on the same twitches. He said this bird had not been seen for around 45 minutes, hence the build-up in hopeful observers, and pointed out two favoured locations on its feeding circuit. Then the American Robin re-appeared on a downland hillside just beyond the cul-de-sac. After Adam left to try for a nearby Hume’s Leaf Warbler, my quest settled quite prominently in the same area and I was able to discern all its features.

Over the ensuing two hours I gained more good though restricted views. The bird was mostly alternating between two locations that could only be viewed effectively by a few people at a time and hardly facilitated RBA’s request to respect the privacy of residents. It wasn’t rocket science to surmise the number of people present was diverting the visitor from the berry-laden spots of the previous days’ RBA gallery (see here). I also heard tales and was shown back of camera images of how it had posed openly earlier.

This first-winter bird has paler and speckled orange underparts by comparison with the rusty red of an adult male, lighter grey head tone and darker bill. Otherwise it shares the slate grey upperparts and prominent white eye ring displayed in all plumages. American Robin is quite heavily built, with long wings and tail, and strong feet.

Eventually I called Adam to see how he was faring with East Sussex’s alternative avian attractions. The Hume’s Warbler had not performed well, and I didn’t need it anyway having had a good experience not too far away in Newhaven three years ago (see here). But he was currently seeking out and finding a Hooded Crow around a service area just out of town on the A27. That was a potential second national list addition of the day for me, and an opportunity too good to miss.

Hence I relocated to Polegate (TQ 578057) where my colleague put me onto the corvid in trees close by the A27. I only needed to tick the thing for Blighty, having seen any number of these abroad in areas where this two-toned grey and black species replaces the all-black Carrion Crow. But I retrieved my car from the service area to drive closer through an underpass and try to get a picture. There another birder pointed out the “Hoodie” perched atop a pylon (above) and that was job done.

It being 2:30pm I didn’t want to negotiate an early Friday rush hour on the dreaded south-western section of the M25. So I opted to return to the first location hoping that with fewer birders in attendance the American Robin might pose on those berry bushes at the end of Hill Road (BN20 8SN – TQ 583004). Back there I engaged with a photographer I know from previous twitches who had been staking out one of the favoured spots for six hours since the bird had last thus obliged.

Things do not get better than what next played out (pictured above). The American Robin fed on the ground, digging for invertebrates just beyond that bush for around 20 minutes. In company with several other birders and photographers I walked around some garages to where there was a clear view, and everyone kept a sensible distance from our subject. Once the show was over the big lens contingent all began to chimp amongst themselves, dismissing as “crap” any back of camera image that wasn’t absolutely pin sharp and perfect, and showing their best results around. For myself I was delighted with the images I had gained. This was by any measure a cracking bird.

It was now 4pm, the light was declining and more new birders began to arrive after work. I hoped it wasn’t too early to brave the M25 and so headed home. If my outward journey had been tedious the return was horrendous, emphasising fully why I normally choose not to bird in East Sussex or Kent. Due to road works on the A27, motorway congestion and three leg stretching stops to counter muscular pain I have been experiencing this winter, the “manageable distance” took four hours to complete. To top everything even the in-car entertainment of a new SMKC album released today largely disappointed, something I couldn’t have imagined ever having to say. But I was returning home with life totals of 375 British and 513 WestPal birds, and nothing could take the shine off that.