Originally descended from the wild Rock Dove, a cliff-face dweller, these birds find the next best thing is a block of flats, a bit of Victorian Gothic architecture or a railway arch. In the absence of natural predators, birds which fall sick survive to infect healthy ones with ornithosis and other diseases, some of which can be transmissible to man. Their accumulated droppings are also sources of disease.
PEST CONTROL GUIDE
The rat has plagued humans for thousands of years – the rat flea was responsible for the Black Death. There are two species of rat in Britain, Rattus norvegicus which is commonly known as the Brown Rat and Rattus rattus which has the common names Black Rat or Ship Rat.
The Brown Rat is the larger, often weighing over half a kilo and measuring about 23cm, without counting the tail. It has a blunt muzzle, small hair-covered ears and a tail that is shorter than its body length. The Black Rat weighs only half as much and is slightly shorter. It has a pointed muzzle, large, almost hairless ears, a more slender body and a long thin tail that is longer than its body.
The Brown Rat is the commoner species and stays near ground level. The Black Rat still occurs in seaport towns and is a more agile climber, often entering the upper floors of buildings. It is possible to identify the species present from the different shaped droppings, footprints in dust (the Brown Rat is flat footed, the Black Rat runs on its toes) and presence of tail swipes. In towns, Brown Rats often live in sewers but in the countryside there is a constant background population in fields and hedges.
Both species breed rapidly and become sexually mature in about three months. Each female may produce from three to 12 litters of between six and eight young in a year.
Brown rats will burrow underground or into suitably soft material to make a nest. Refuse tips, loose soil under sheds and earth banks are all likely sites and chewed paper, straw or insulation material may be incorporated as nest material. The young are born blind, helpless and naked and depend on their mother for food for about three weeks before they are sufficiently developed to take solid food.
Rats, like mice, need to gnaw to keep their constantly growing incisor teeth worn down. They damage woodwork, plastic and lead pipes and will sometimes strip insulation from electrical cables by their gnawing.
Rats will hoard food for future consumption and numerous cases of “theft” have been found to be the work of rats. They feed mostly at night and an average rat will eat 50g of food a day.
Creatures of habit, rats leave regular “runs” to and from feeding areas. They can be a menace to poultry, eating eggs, chicks and animal feed.
They are also capable of spreading many diseases from their filthy surroundings in sewers or refuse tips and can transmit food poisoning, Weil’s disease (from which about ten people and a number of dogs die each year in the UK), murine typhus, rat bite fever, trichinosis and other diseases. They are probable carriers of foot and mouth disease on farms. They contaminate more food than they consume and their urine can pollute stagnant water.
Tiny, bright red specks, about 1mm across, sometimes move into buildings in large numbers. There are two species with several names, generally known as Red Spider Mites. Although they do no direct harm inside the house, if the mites are squashed they stain walls and decorations.
It is the female mites, also known as Clover Mites and Gooseberry Mites, which invade homes and other buildings in spring and autumn, climbing walls to seek egg-laying sites or places in which to hibernate.
According to entomologists male Red Spider Mites are “hardly ever found”, because the females lay their eggs parthenogenetically -ie. without the benefit of male involvement.
There are two species with different habits. Bryobia is dull red, moves slowly and feeds on plant sap; while Balaustium is bright red, runs quickly but erratically, feeds on pollen and lays its eggs in cracks in walls or the soil.
Correct identification is important – for if you grow grass around a building to discourage Balaustium, you may get Bryobia and if you put down concrete to discourage Bryobia, you are likely to get Balaustium!
A cigar-shaped, silver-grey, wingless insect about 12mm long, found in damp areas commonly in kitchens and bathrooms. Nocturnal in habit, but often trapped in baths, basins or chinaware as it cannot climb the smooth surfaces. Moves quickly and has three long bristles at the tail end.
Occasionally damages paper but feeds on residues of starchy substances such as glues, wallpaper paste and carbohydrate food debris. It may indicate damp conditions which need attention.
Eggs are laid in cracks and crevices and the nymphs grow by an indefinite number of moults. Can grow a new leg if they lose one. Adults can live for over three years.
A closely related species, the Firebrat, is flatter and speckled, without the metallic appearance, and favours hot, dry situations, but can still be destroyed in the same way as its cousin.
A mollusc, occasionally found indoors, in damp areas such as cellars.