How the frog found water nine inches up in the air and why it chose that in preference to a ground-level pond comes down to amphibian sensory biology, microclimates, and behavioural ecology. Frogs do not map elevation, but navigate by line-of-sight, moisture, and smell. They can detect humidity gradients as well as the scent of stagnant water or moist organic matter some distance away. During a heatwave, the air above the birdbath creates a localized microclimate of higher humidity, enabling the frog to follow humidity gradients, effectively sniffing and feeling its way toward dampness and bliss.

Because the birdbath sits beside a shrub, the frog probably hopped into its foliage seeking shade before stumbling upon the birdbath. Amphibians display strong site fidelity; when exploration yields a life-saving resource such as water, they remember it and will return repeatedly. Knowledge of its whereabouts could be a life-saver.

If I was a thirsty fly, I would be worried. Very worried!

Choosing the birdbath over a ground-level pond makes some sense. Ground-level water sources attract predators like cats, birds, and grass snakes, all seeking water, whereas a raised birdbath offers an elevated sanctuary somewhat out of reach of many earth-bound predators. Also, having introduced frogs to the garden over the last few years makes larger ponds centres of territorial or breeding-ground competition among the resident adult population here. In contrast, the birdbath may serve as a peaceful, uncontested haven somewhat away from many predators and rivals. But the splatterin stushie of blue tits, sparrows, and other feathered loons must be a sore trial.

Permitting me to top up the water until it is submerged neck deep suggests the frog's behaviour is driven by a desire or need for cutaneous absorption and thermal regulation rather than selecting a hunting stance. Amphibians do not drink through their mouths; they absorb water and salts through a specialised drinking patch of skin on their pelvis and belly. Submerging to its neck efficiently rehydrates its entire body. Allowing me to add water while it stays put also suggests a degree of habituation; our regular encounters have maybe taught the frog that I am not a threat, but rather the bringer of gifts in the form of a welcome influx of cool water, overriding its initial instinct to flee.

Ultimately, the frog is using the birdbath to beat the heat. Frogs are quintessential sit-and-wait predators, so when they find themselves in a micro-habitat that happens also to attract potential prey they will rarely resist the chance of a free lunch. In a drought, small bodies of water such as the birdbath act as magnets for all kinds of flying insects, (such as mosquitoes, midges, and various flies as well as wasps and bees), all looking for moisture or a place to lay eggs. Frogs exploit the 'Oasis Effect' to set up shop and await dinner on the wing - self-propelled pizza, no drone required.

With good vision attuned to movement triggering a predatory response, a dark shape moving within a frog's visual field is all the stimulus a frog needs to respond with a tongue-snapping reflex with no need for complex, forward planning. Even submerged to its neck, the birdbath is an ideal hunting ground for an opportunist hunter. Insects land to drink or lay eggs, putting them right at eye level of a semi-submerged frog. The frog uses the birdbath as a climate-controlled spa to soak up moisture and snap up passing meals without expending energy or risking exposure to predators looking for their own free lunch.

It seems this frog's enterprising spirit was insufficiently advantageous to pass to succeeding generations. Visits to the bird bath continued for a few days then ceased, even though the heat wave lasted another week or so. A couple of days after noticing the frog's dilatory appearance I saw a buzzard alight on a tree overlooking the garden. I threw a rotten apple at it. It flew off but the frog was not seen again.

Sic transiit gloria ranae.