Features

Summer Sights and Sounds

As the frantic rush of spring fades, nature settles into a contented summer hum says Martin Brennan.

As peak summer season passes the melodious sound of birdsong gradually fades with bird breeding season coming to an end. The verdant vegetation cloaking the countryside provides cover, protection and seclusion for its many inhabitants. It absorbs and muffles sound giving the illusion of inactivity and the relative silence of summer. The droning and buzzing of a diversity of insects, active on these warm days, is now manifest.

Stunning orchids

The interaction of underlying geological formations, soil characteristics, climatic conditions and living organisms results in our rich variety of grassland types, and it is here that insects are most evident. The range of grasses and herbaceous plants support varying invertebrate communities to which they have adapted. Amongst plants the orchid family produces some of the most colourful species, displaying an attractive array of shades, sizes and shapes in succession through spring and summer. These are found predominantly in calcareous and neutral grasslands and dunes. Many have symbiotic relationships with soil fungi. Their impressive, generally densely-spiked blooms have one petal of each individual flower within this mass enlarged and modified to form a lip, giving them their distinctive character. There are the pink or red common-spotted, heath-spotted, early purple, pyramidal and marsh orchids and the fragrant orchid with its vanilla perfume. Delicate pale cream, white or green coloured species include lady's tresses, with its flowers spiralling around the stem, twayblade, butterfly orchid and the dense-flowered orchid. In addition there are the stunning, darker coloured, velvety, insect-like bee, spider and fly orchids which mimic and resemble these insects to trick and attract them for pollination purposes. The taller helleborines add further to the range of colours and flower shapes, with their reds, purples and browns. An assortment of other flowering plants adds to the pastel of colour waving in the breeze. The insect population attracted by this profusion of nectar-bearing vessels adds sound and motion. The lazy fluttering flight of butterflies, the hum of hoverflies as they hang motionless in the air, and the background buzz of bumblebees compliment the visual stimulation creating an enveloping serene and soothing atmosphere in this "pleasant lair of wavy grass".

Beautiful butterflies

Butterflies are the most distinctive and colourful of the insects inhabiting grasslands. They metamorphose through a number of phases - egg, larva/caterpillar and chrysalis/pupa - to develop into the adult winged beauties which they become. Most species are associated with specific plants, or a limited range, on which they exclusively depend at different stages. The gardener is familiar with the large and small white butterflies or "cabbage whites" which can do much damage. These may, however, be mistaken for other harmless "white butterflies". The smaller Wood White most closely resembles them, and, as the name suggests, occurs mainly in woodland clearings. It lacks the black wing spots of the former. Its eggs are laid singly on the undersides of vetches, and the adults feed on the nectar of a range of plants including bird's-food-trefoil, bugle and ragged robin. The Green-veined White with its delicate pale green veining on the underside of its wings is found mainly in wet meadows and damp woodland margins. The Orange Tip has a very attractive marbled pattern on the undersides of the wings in both sexes, although the distinguishing markings giving it its name are carried only by the males on the upper wing surfaces. They lay eggs singly on the blooms of cuckoo flower or ladies smock on which the caterpillars feed and develop. Wild members of the cabbage family are the food plants of both species. Those true grassland species which lay their eggs on grasses include Meadow Brown, Ringlet and Speckled Wood. Other butterflies of grassland and hedgerow include Common Blue, Small Copper and Brimstone, one of the earliest.

Doughty travellers

Amongst the larger butterflies Small Tortoiseshell, Red Admiral, Peacock and Painted Lady, the aristocrats, are easily distinguished by their rich colouring and bold markings. They lay their eggs on the undervalued nettle. The adults feed on a small number of wild plants and can be attracted to gardens by buddleia (butterfly bush) and ice-plants. Rotting fruit in orchards also attracts them in large numbers creating a colourful spectacle in the autumn. Quite amazingly both Painted Ladies and Red Admirals are migratory, arriving annually from south-west Europe. They do not return and generally do not survive over winter. Eggs laid by early migrants give rise to a second generation later in the year.

The aptly named bumble bees fly rather awkwardly, their relatively small wings appearing to defy logic, yet effectively carrying their bulk. They play an important role in the pollination of crops and flowering plants. Six of our thirteen species are in decline, as are a great many of our solitary bees. Loss and fragmentation of habitats, changes in farming practices and increasing use of pesticides are contributory factors. Industrious wasps establish colonies in summer, and being carnivorous, provide an invaluable service by consuming large volumes of aphids and other insect larvae.

Flashes of colour

Along rivers, streams and in wetlands, including bogs, dragonflies and damselflies dominate the insect populations. They surpass in beauty, iridescence and delicate design even the butterflies. The array and combination of glossy sheens is truly eye-catching. Their transparent, stained-glass-like wings glisten and sparkle in the sun. Damselflies fold theirs along their bodies when at rest, in contrast to those of dragonflies which are outstretched. Both spend the greater parts of their lives underwater as nymphs, ferociously predators of other aquatic creatures. In their adult winged form they are also carnivorous, catching their insect prey on the wing, the legs forming a "basket" to scoop it from the air. The descriptive names capture and attest to their striking beauty and magnificence - Beautiful Jewelwing, Downy Emerald, etc.

Bats in the attic

Moths, mainly nocturnal, and numerous other night flying insects continue activity around the clock, and with such a readily available food source, bats, being exclusively insectivorous, capitalise on the abundance and provide a valuable service, by controlling their numbers. Bats have a unique and fascinating life-style. The only mammal in the world with the capacity for true flight, they have good sight, but have adapted to night navigation by means of an ultra-sonic sound system. The emitted sound pulses, reflected back from solid objects, provide them with details of their surroundings, enable them to detect the presence of prey and precisely locate, track and catch it. They hibernate in winter, having mated in the autumn, although fertilization is delayed until spring when they re-emerge. Summer is their season for rearing young. Females establish nursery roosts, from about June, in a range of sites, depending on the species.

Pipistrelles are most frequently found in attics and behind fascias of domestic dwellings. They can gain access through tiny openings and may congregate in fairly large numbers. Brown long-eared bats, easily recognised by their very large ears, may also be found, at more exposed locations along the rafters, in attics, suspended by their feet, in contrast to the former which form tightly packed clusters in crevices or corners. Lesser horseshoe bats, recognised by their characteristic horseshoe-shaped "nose leaf", also hang upside down in attics, lofts or caves, with their wings wrapped around them. They cannot crawl and require an un-interrupted flight path to the roosting area. Daubenton's bats, usually associated with and found feeding over water, tends to roost in stone buildings and in crevices under the arches of bridges. Natterer's and Whiskered bats both haunt woodland; the latter especially in those with rivers or ponds and the former also in pasture. Summer roosts for both can include tree cavities and older buildings. Our remaining species, Leisler's, is a fast, high-flying species favouring wooded areas and parks. The breeding roosts are a short-term, seasonal occurrence, with the single young being weaned and the site vacated by the end of September.

While nature appears silent in summer, it is just an illusion, with much activity taking place either hidden from gaze by the cloak of vegetation, or under cover of darkness. Insects are its most visible manifestation during the daytime, displaying natures diversity in its most colourful and delicate magnificence, yet uniquely adapted to exploit specific niches in the environment.

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