Features

Winter Wonders

In his final column, written earlier this year, Martin Brennan explores the diversity of the natural world in winter.

At this time of year, as we gradually and imperceptibly progress from winter into spring, the shape and form of the bare and bony landscape is revealed in the absence of vegetation clutter. The low light and angle of the sun add mood and cast in relief features not otherwise visible underneath that cloak. Denuded and stripped back to its essential framework, the varied topography which gives the countryside its character is revealed. The structural skeletons of trees and woody species add beauty to the winter scene. That inviting green mantle which cushions everything in summer will now be recycled, its nutrients extracted through the processes of decay and decomposition, and reabsorbed for contribution to the forthcoming season’s growth.

Winter Food

Revealed also is the extent and spread of ivy growing on trees and in many other locations. An invaluable plant, it contributes greatly to the well-being and survival of many forms of wildlife.

Just now, its ripe berries are a scarce source of nutrients for native Thrushes and Starlings and for migratory Redwings and Fieldfares, at a time when most such food is exhausted. It is a refuge for many birds and also for hibernating insects such as queen wasps and occasional butterflies. The excited activity of flocks of murmuring starlings as they settle down for the night to roost in it is cheerful and soothing to the ear.

In spring/early summer ivy provides cover and nesting sites for a range of birds, and during autumn its rare late flowering habit provides a source of nectar for insects. An added advantage is ivy’s evergreen quality, enhancing its value and providing contrast in what can sometimes be a bleak winter landscape.

The tiny Holly Blue butterfly has adapted to and depends upon it. It produces two generations each year, the autumn generation feeding on ivy flowers and the spring generation on those of holly – unusual for butterfly larvae to have different food plants at different times of year. All in all, ivy is a very versatile plant effectively representing a habitat in its own right and a valuable niche for specific creatures.

However, given its ubiquity, due partly to its adaptability to dark, damp conditions, it requires some control and management to prevent trees and woodland ecosystems from being overgrown by it. Thus we may continue to appreciate their individual beauty and architectural form, while retaining sufficient amounts to enhance their wildlife value and habitat diversity.

Mossy Carpets

Winter, in addition to providing an opportunity to look at the bigger picture and the wider landscape pattern, is also an ideal time to examine some of the more delicate details of smaller organisms.

Mosses are most luxuriant at this time of year when moist conditions suitable to their requirements persist. Where these needs are satisfied they vary in form, colour and pattern, carpeting for example woodland floors, enveloping tree trunks and branches in a soft protective covering of tiny fronds, forming hummocks and mounds in other locations and softening the harsh, jagged profiles of rocks. In bogland the russets and pale greens of water-absorbing sphagnum mosses provide contrasting colours, giving a very deceptive appearance of a solid surface.

To the naked eye, but even more so when magnified through a hand lens, they provide exquisite detail in the form of feathery filigrees representing natural artwork of the finest form. Some have flattened, frondose heads of branches, others have minutely-toothed oval leaves, others still elegant plumose or feathery plants, densely and very finely branched. The seed or spore capsules usually standing proud of the plants add further to their diversity, character and colour.

Colourful Lichens

Lichens also provide an equally impressive display of apparently brittle structures, often in conjunction with mosses in woodlands, festooning branches and twigs with their fragile beauty. Along the coast they crust and add colour to rocks and cliffs, but are found in most habitats, and are valuable indicators of air quality. They range from crustaceous types which closely cover their hosts in a thin scalytype crust as on tree trunks and rocks, to foliose forms which develop leafy growths with distinct upper and lower sides and to fruticose or shrubby lichens which form clumps or clusters of intricately designed patterns and colours, encircling and hanging from branches.

Lichens represent a combination of an alga and a fungus in a symbiotic relationship. The former produces the green chlorophyll which builds up carbohydrates through the process of photosynthesis, which are then distributed and absorbed by the adjoining fungal hyphae and utilized for growth.

The latter provides a protective cover shielding the alga from intense light, drought and heat. Like mosses, few have simple names but among them are the jelly lichens and beard lichens, which as the name suggests, are quite finely branched and “hairy”. The cladonia species develop most delicate, slender, shrubby branches with cupped ends, almost coral-like, often of a different colour, frequently red, to the main plant.

Lichens display an amazing array of colours, shades and forms including pale greys and greens, yellow, orange, red, brown and black and practically all the various shades in between.

Migratory Species

Winter also provides opportunities for bird observation, and most appealing is the influx of huge numbers of migratory wildfowl and waders. Winter migrants represent the true intrepid travellers of the bird world, displaying feats of endurance and inhabiting harsh, cold, wet environments throughout their annual odysseys.

The summer breeding season is spent in locations scattered across the northern hemisphere, mostly at high latitudes. They travel long journeys from locations as far apart as the Canadian Arctic, Greenland, the Russian tundra and northern Europe. These are birds of the real wilderness, providing a connection to some of the most wonderful wildlife environments in the world. They are found around our coast in its bays, estuaries and mudflats, where their daily cycles are dictated by the tides, and on wetlands including lakes, bogs, marshes, fens and river systems.

Among them are ducks, geese, swans and waders, usually present in large flocks, and often including many or combinations of all these families. While waders (long legs, long bills for probing mud) may appear pale, dull and grey at a distance in winter they dramatically dress up and alter their appearance for the summer breeding season.

Winter visitors provide fantastic aerial displays as they gather in huge numbers to show amazing aerobatic skills, performed in tight formations, flashing their colours and twisting and turning in unison at high speed.

The V formation of geese and swans in flight is beautiful to behold. And what is more primordial than the bugle call of the Whooper swan, even at night, conjuring up visions of the remote wilderness locations whence it came.

Explore And Learn

Resident and migratory song birds can now be more easily observed, particularly in close proximity, if food is provided for them. Their behavioural habits and individual calls (as opposed to song) can be learned and identification techniques honed, in the absence of vegetation. This knowledge can be built upon in spring/early summer by familiarizing oneself with their songs while they are still visible before new vegetation once more cloaks the countryside in a mantle of green and hides them from view.

Now is an ideal time to appreciate landscape form and topography cast in low light and highlighted in mood-creating conditions to best effect. Wetlands also yield up a fantastic array of migratory birds which are both diverse in plumage and form, and for added value perform aerial displays of amazing quality to rapture and enthrall. So get out, explore and view nature’s winter wonders while still on show.