My other find was surprising for a quite different reason. Early each year, when the main influx of goosanders arrived on the river, there would sometimes be a pair or two of red-breasted mergansers accompanying them. These are sawbill ducks too, close relatives that breed near to the coast. They are finer, smaller birds, and the male, at least, is quite distinctive, with grey flanks in comparison to the pure white of the male goosander, and of course the red breast for which it is named. But when the males left the river soon after, the redheads were much harder to distinguish. Smaller and skinnier, with a slightly more obvious shaggy crest, perhaps. One year I thought I had seen a female with her brood, but it was hard to be sure when the redheads were forever in the process of disappearing around the next bend in the river, and then the next. Then the following year, when I was on the heavily wooded section of bank nearest my home, something crashed out of the thick undergrowth at my feet and splashed down into the river. She began to circle close to the bank, flapping her wings and panicking but unable to flee, torn by conflicting impulses. From this close up there was no doubt that this bird was different from those I regularly saw. I checked the place where she had emerged; beneath the thick ground layer of riverside plants was a hidden trail, almost a green tunnel. I followed it back ten or fifteen feet to a secret hollow in the bank where eleven nearly spherical white eggs were hidden. They may be close relatives, but in this respect at least their habits differ markedly from their larger cousins. Unlike the goosanders with their tree-hole nests, the mergansers are ground nesters. Old records show that, long before goosanders moved south and took over the rivers of Wales, there were occasional sightings of mergansers on the river here. My suspicion is that they have always nested here in small numbers, but have been overlooked, and when their bigger, brassier relatives arrived, they simply merged into the crowd, and disappeared from view altogether.
As far as the woodland creatures were concerned the fringe of riverside trees along the river’s length constituted a very long, thin wood. Badgers left their trails all along the bank and dug latrines to mark their territorial boundaries. Flycatchers dashed back and forth across the water. Sparrowhawks worked the beat, soaring above the treetops, then pausing to circle, then soaring, then circling again, as if they could not fly as slowly as necessary, as though they were worried they might have missed something important.
Working my way downriver through a thickly wooded section, I surprised a buzzard right at the water’s edge just beginning to pluck a dead carrion crow. I must have missed the kill by seconds. The buzzard lifted off with the crow in its talons and set off across the river, but the weight must have been too much for it, for it dropped the crow midstream, and it fell with a splash right in the middle of the river. As I walked on along the riverbank the floating body stayed alongside me, matching my pace exactly and making me ponder the possibility that I had perhaps been accompanying the very same shower of raindrops for the whole day, as the landscape and the birds changed around us. After a minute or so, a second crow arrived, and began to circle and swoop over the floating body of what I had to assume was its mate, making calls of the utmost distress. It was very sad — crows pair for life. But what happened next took me aback. Over the course of the next minute or two, more crows began to race to the scene, flying in from every direction, until there were twenty or thirty of them wheeling and diving and calling above the dead bird. These are not in any way social birds, but crisis had brought them together and I felt as though I was witnessing a crow wake. And then, as suddenly as they had arrived, they all began to disperse, and it was once again only me and the black corpse drifting downriver side by side. Far above us hung a single red kite, waiting for the body to drift ashore.
With the end of the year’s river-bird survey I could revert to a less structured relationship with the river. I would often head down the hill to the footbridge and position myself halfway across. From high above the water and midway between its banks I had a quite different perspective on the river and could see much further both upstream and downstream than I could from almost anywhere at the water’s edge. If I had been busy that day chopping wood or digging, it was a particular pleasure to stroll to the bridge at dusk. There was a pair of semi-detached estate cottages near by, with a shared roof space that was home for a colony of long-eared bats — a colony at least ten times the size of mine. As darkness fell, the bats would come streaming out from under the eaves and hurry to the riverside and its trees, swooping and diving all around me. The river had its own bats too: Daubenton’s bats, which skim the river, feeding on the midges and flies that live in the inch above the water’s surface, and even snatching insects floating in the water, so that they look as if they are bouncing across the water like a skimming stone. These are not house-dwelling animals; they roost in crevices in trees, always close to water, and the university had put bat boxes in the woods all along this stretch of the river. They were much higher in the trees than the bird boxes, as is the bats’ preference, high enough that they could be inspected only by ladder, and they had a narrow slot for the bats to enter rather than the round entrance hole that would have let in the birds.
The bats would swirl all around, passing within inches of me as darkness fell, their most active time. To my ears there was nothing beyond the quiet churning of the waters below me, a screaming silence, but to them there must have been a cacophony of sound. It is almost impossible to comprehend how they must perceive the world: they map everything around them, creating a mental image from sound as we create an image from light. When it was too dark to watch them any more I would set off back up the hill, and on a moonless night, with clouds to hide the stars, it could be almost pitch black. But if I kept to my regular route I would have no problem: I had my own mental map of the journey home that I had built out of memory. Time and distance, the texture of the ground beneath my feet, and its incline, aided by the slight fluctuations in the density of the darkness that would tell me whether or not I was beneath the trees.
There was something extraordinary about the bats, something apart from the obvious extraordinary things. As they circulated around me and hunted for their breakfast, they treated me no differently from how they would treat the branch of a tree: as an obstacle, not a threat. And in this respect they were different from almost every other mammal or bird. So many of my most memorable encounters with wildlife were those occasions when there was a breakdown in the natural order of things — the natural order of things being that wild creatures sense us coming a mile off, and run like hell. Those moments that felt to me like intimacy, like closeness to nature, must undoubtedly have seemed quite different to the animals involved. The injured raven in the hand. The plover with her eggs, or the mandarin with her young, each torn between conflicting impulses: the maternal instinct and the urge for self-preservation. Even the garden birds that we watch with pleasure at our bird-feeders are in a state of conflict: safety or hunger. When the weather is at its worst, more and more birds throng to the table, because the alternative to facing their fear is starvation. It is easy to sentimentalize nature, to forget that the prevailing forces at work — besides the urge to hold a territory and find a mate — are hunger and fear. Our position in nature is anomalous: we are the pole predator and almost everything fears us, while most other predators in the animal kingdom are themselves running scared. The sparrowhawk fears the goshawk just as the chaffinch fears the sparrowhawk, and with good reason; when the goshawks move in, the number of sparrowhawks inevitably falls.