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Nature

The Heene Cemetery Nightshift

Carpe diem (Latin: Seize the day) is not a mantra that some of our wildlife residents and visitors observe; carpe noctem (seize the night) is their lifestyle mission, although the latter phrase, unlike the former, does not appear in the Latin writer Horace’s Odes. Biologists use different terms to describe the lifestyles pursued in different degrees of light intensity. These choices are made to reduce competition for food and other resources, to avoid some predation, to minimise risks when breeding, and to take advantage of, or to avoid, conditions such as shade and moisture, or warmth and dryness. Being active during daytime is ideal for animals whose eyesight is not strong, and animals active during the night reveal themselves by their larger eyes. Predators naturally target their interactions with potential prey according to the lifestyle choices made, whatever the clock shows, and in the cemetery these interactions never wane, even if there may be nobody to witness them.

An animal active only during the hours of darkness is called nocturnal, and our grunting prickle of hedgehogs is an example. One of their favourite foods in the cemetery is that nocturnal gastropod the slug, and we have several species. Animals active only during the hours of daylight are called diurnal, and most of our resident and visiting birds fall into this category. Those animals that venture out in the twilight, before sunset, and before sunrise, are referred to as crepuscular, and many moths are about at these times. In the dead of night they would be sitting ducks (or should I say sitting moths) for bats. We have diurnal, crepuscular, and nocturnal moths but suspect there are many more species of each that we haven’t yet discovered. An animal active only during the evening, such as some species of fly, is called vespertine, and an animal active only during the dawn period from first light is called matutinal, such as some bees. We have recorded many species of fly but there may well be more that we don’t see because they hide during the day. Our known species of bee have been observed during the daytime, but probably others are in the cemetery and have completed their foraging before the conservation team arrives.

Heene Cemetery at night - winter scene
Heene Cemetery at night at spring time

Mammals diversified during the dominance of the dinosaurs, and to escape the predatory inclinations of the carnivorous species of these reptiles they adopted a nocturnal lifestyle and evolved small body size for easy concealment. Throughout the world today there are still large numbers of small, nocturnal mammals. In the cemetery we have the large-eyed wood mouse, which only appears during the day after the bird feeders have been filled up! One can also detect the ammoniacal urine of the house mouse, but this species has not yet been seen and photographed. The best-known nocturnal mammals are of course the bats, and the common pipistrelle is regularly seen hunting flying insects over the cemetery after the light fades. Along the south coast in more semi-rural areas not far from Worthing there may be found three other bats, the soprano pipistrelle, noctule and serotine, and it may be that they make occasional forays over the cemetery but have not yet been observed. Using a bat detector in an urban area is fraught with difficulties because of interference from electrical equipment being used in houses and from vehicles like mopeds without suppressors.

Most of the birds that frequent the cemetery are diurnal, but there are early risers and late sleepers. When the dawn chorus starts the first singers are usually members of the thrush family, especially the robin and blackbird, which have strong territorial instincts, although we have also recorded the song thrush and mistle thrush in the cemetery. In the evening the last singer is usually the chaffinch, and when all is silent except for this prolific singer it can be quite inspiring. However, I remember taking a party on a woodland walk one evening in late Spring when the chaffinches were at their loudest and a thoroughly bored, intolerant youngster took a moment away from her mobile phone to ask, “Can’t those chaffinches be switched off?” The short, sharp call of the tawny owl is commonly heard in south coast villages but has not yet been reported from Heene Cemetery. It is the most likely owl to visit an urban location, but only if there are sufficient small mammals, amphibians and birds. Few of these are actually resident in the cemetery.

Heene Cemetery at night in summer
Heene Cemetery at night in summer

Our resident amphibian, the common frog, is crepuscular and nocturnal, avoiding the desiccating effects of sunshine, and feeding mainly on insects, slugs and worms. Adult amphibians only need to return to water to breed, not to feed, so the moist, shady areas of the cemetery are also suitable for toads and newts that have bred in neighbouring garden ponds. Of our two known reptile residents, the common lizard and the slowworm, it is the latter that takes advantage of the coolness of the night to feed, slugs being one of its preferred foods. Lizards are fond of basking in the sun and feed mostly on diurnal insects and arachnids.

We know surprisingly little about the habits of soil organisms within a 24 hour period because the absence of light means that it is other factors that determine their lifestyle. When we have hot, dry weather they tend to go deeper, and can even go into a resting phase (called diapause) until cooler, moister conditions return. They may do this in cold winters too, like earthworms, of which we have several species, which coil up and envelop themselves in mucus to create a humid microclimate around their bodies. We are gradually discovering the habits of our species of centipedes and millipedes, but as we restrict digging in order to preserve soil structure and fertility they are rarely observed. Almost certainly there are more within leaf and twig litter and the topsoil and they will vary the depth of their activities according to the prevailing conditions, venturing higher up and on to the surface when it is moist, and this is most likely outside the summer months. Of our molluscs, all are gastropods, species of snail and slug, with slugs more likely than snails to be seen after sunset, especially if it has recently rained. We have plenty of woodlice, and the species of this crustacean group discovered so far do an excellent job overnight recycling dead plant material.

Some insect groups are mainly nocturnal, such as the mayflies, but these delicate animals are unlikely to be found in the cemetery because we have so little standing water. This is also the reason why dragonflies and damselflies are mainly visitors to the cemetery. Grasshoppers and crickets abound because we allow grasses and other herbaceous plants to grow to full height, and insect species of bugs, beetles, ants and wasps are well represented in this diverse habitat, which is never treated with chemicals of any kind. These insects are all diurnal, as are our many species of butterfly. Our arachnids, mostly species of spider, are also diurnal. The abundance of invertebrates demonstrates the ecological health of a habitat rich in native fungi, flowering and non-flowering plants.

We have still much to learn about the comings and goings of the Heene Cemetery nightshift, but before too long we hope to have a much clearer picture of what happens in the mysterious world of the cemetery after the conservation teams have gone home and the light fades.

Written by Brian Day