Corvidae - Stone the crows!
It's a pretty safe bet to say that most people living in the United Kingdom have seen a crow, except maybe those who have never ventured away from the Highlands of Scotland. They may not realise it, but seen one they have.
Corvidae, to give them their latin name, are a family of birds that can be found all over the world. Here in the UK, there are eight species, ranging from the colourful and small (ish) Jay to the almost buzzard sized Raven.
The UK family roughly splits into two distinct sizes; Jays, Jackdaws and Magpies, which are the size of a feral pigeon, and the much larger Rooks, Carrion Crows and Hooded Crows. In between these two groups sits the Chough, a rare species that lives on rocky coasts and mountains of Wales, West Scotland, Northern Ireland and Southwest England. The UK family is completed by the massive and heavily built Raven.
They are the largest of the UK's perching birds and all walk with a somewhat cocky strut not dissimilar to Liam Gallagher. In contrast, they are regarded as the most intelligent of birds.
The larger variants are often painted as 'evil', with many portrayed as such in horror movies, Halloween stories and tales of witches and warlocks. Crows were the undoubted stars of Alfred Hitchcock's iconic film 'The Birds', whilst many a religion portrays them as the harbingers of doom or death.
It is believed, by some, that the "four and twenty 'black' birds baked in a pie" in the nursery rhyme Sing a song of sixpence were rooks rather than the much smaller blackbird although, as many argue over the origins of the song, let alone the intricacies of the lyrics, it is impossible to ascertain if there is any truth in this. It does seem more likely though, as the rooks' nesting habits are often regarded as a nuisance.
"One for sorrow, two for joy, three for a girl and four for a boy" concerns the magpie, and many folk still salute, wink or nod to a single individual to ward off bad news.
In many parts of the country during the 17th Century, where choughs would have been common, they were known as the Crow of Cornwall. The bird sits proudly atop the county's crest to this day. Legend has it that the soul of King Arthur departed this world in the form of a chough, the red feet and bill signifying Arthur's violent and bloody end.
A group of six captive ravens live at the Tower of London. Their presence is traditionally believed to protect the Crown and the tower; a superstition holds that "if the Tower of London ravens are lost or fly away, the Crown will fall and Britain with it."
So, there you have it, the stuff of myth and legend but, from a conservation perspective, what threat, if any do they pose?
It is perhaps a good idea to look at each bird individually, as they all have distinctive habits, but also share some traits.
First up is the most colourful member of the crow family; the jay. These shy woodland birds, rarely move far from cover and are, subsequently, quite difficult to see. Their screaming call gives their whereabouts away and this is usually given when they are on the move. They are expert fliers in this habitat and a distinctive flash of white on the rump and azure blue on their wings is often all that anyone gets to see. Jays are famous for their acorn feeding habits and, in the autumn, they bury acorns for retrieving later in the winter.
Their diet is mainly acorns, nuts, seeds and insects, but they will also take nestlings of other birds and small mammals should the opportunity arise.
The are found right across the British Isles, apart from the far north of Scotland and the northwest coast of Ireland.
Magpies are jacks of all trades - scavengers, predators and pest-destroyers. Their challenging, arrogant and aggressive attitude has won them few friends.
With its noisy chattering, 'black-and-white' plumage and long tail, there is nothing else quite like the magpie in the UK. When seen close-up, its black plumage takes on an altogether more colourful hue, with a purplish-blue iridescent sheen to the wing feathers, and a green gloss to the tail.
Given their striking plumage, they are amongst the easiest of British birds to spot and will often be seen flying away from road kill as you approach. Perhaps their worst feeding habit is seeking out nesting birds to feast on the eggs and hatchlings. Where non-breeding birds have gathered together in flocks, this can have a devastating affect on local populations of other species.
Their range extends across the British Isles apart from the Highlands of Scotland
The first of the 'black' crows, Jackdaws have a distinctive silvery sheen to the back of their heads and piercing pale blue eyes.
They appear to delight in flying - the stronger the wind the better - and flock together at dusk and dawn in large numbers to return to and from their roost, all the while calling out 'jack'. It's a spectacular sight and sound. In winter they will also flock with larger crows in huge numbers.
Their diet is a bit of both of the jay and magpie, with insects, young birds and eggs, fruit, seeds, scraps and carrion sustaining them. They are also partial to chafers and leatherjackets, but will also happily wait around for adults to emerge, picking them off as they do so.
The jackdaw's somewhat annoying habit of nesting in chimneys (at least for the owners) has diminished with modern housing. Cliffs, tall buildings, crevices and holes in trees, where they have been known to out-compete tawny owls for desirable residences, are now preferred.
Their range mirrors that of the magpie.
Like the smaller crows above, the chough (pronounced 'chuff') is on the RSPB's green list but, with under 500 breeding pairs in the British Isles, all confined to the west coast of Cornwall, Wales, Scotland and Ireland, plus the Isle of Man, it is 'vulnerable' to change.
Whilst its black plumage identifies it as a crow, the chough has a red bill and legs unlike any other member of the crow family. It is insectivorous, so poses no threat to other wildlife; other than insects, obviously!
It readily displays its mastery of flight with wonderful aerial displays of diving and swooping and it is believed that its joy of aerobatics in the thermals and strong winds around the coast dictates its range. Where numbers allow, the chough forms flocks in autumn and winter.
The all-black carrion crow is one of the cleverest, most adaptable of our birds. It is often quite fearless, although it can be wary of man. They are fairly solitary, usually found alone or in pairs. Carrion crows will come to gardens, refreshment kiosks and clubhouse areas for food and, although often cautious initially, they soon learn when it is safe, and will return repeatedly to take advantage of whatever is on offer.
Though, as its name implies, it is an eater of carrion of all kinds, the carrion crow will eat insects, earthworms, grain, small mammals, amphibians, scraps and will also steal eggs, although its size makes this activity somewhat prohibitive.
Crows are scavengers by nature, which is why they tend to frequent sites inhabited by humans in order to feed on their household waste. Crows will also harass birds of prey or even foxes for their kills. They actively hunt and occasionally cooperate with other crows to make kills. They have become highly skilled at adapting to urban environments.
Hooded Crows (Corvus cornix)
The hooded crow's range in the British Isles is the complete opposite of the carrion crow, i.e. all of Ireland and north and west Scotland. Until quite recently, it was regarded as a sub-species of the carrion crow, but has now been classified as a separate species.
In all aspects, its lifestyle mirrors that of its close cousin. Where their territories crossover, some interbreeding occurs.
Rooks (Corvus frugilegus)
As far as greenkeepers and groundsmen are concerned, this is the daddy of all the crows. Whilst a bit of jewellery theft or egg stealing can be tolerated by most, pretty much everything the rook does is designed to aggravate!
Rooks are very sociable birds, and you're not likely to see one on its own. They feed and roost in flocks in winter, often together with jackdaws, and build their nests in a tree-top commune known, unsurprisingly, as a rookery.
The nests are bulky and made from twigs bound together with earth, lined with moss, leaves, grass, wool, hair, etc. Nest building usually begins in late January/early February, although previous years' nests may be renovated and reused. The whole business is a thoroughly noisy and disagreeable affair, as anyone living or working near a rookery will testify. There is also the additional hazard of being bombed on from a great height by all sorts of unpleasantries.
Rook shoots, undertaken by local farmers, gamekeepers and landowners were once a regular occurrence, but are now prohibited by law.
However, it is when rooks and other crows descend onto fine turf in search of leatherjackets and chafer grubs that they are cause for concern, as the damage they do is considerable.
Of course, it's easy to say "cure the cause" but, with chemical control no longer an available option, that will be easier said than done.
The raven is massive - the biggest member of the crow family. It is all black with a large bill, and long wings. In flight, it shows a diamond-shaped tail.
The raven's range stretches from the west coast of Ireland right across to a north/south line through Scotland and England, although they are currently expanding eastwards.
They have a preference for upland areas. Most are resident, although some birds - especially non-breeders and young birds - wander from their territory, but do not travel far.
Apart from their size, they may be distinguished by their call, which is not unlike a washboard being continually scraped by a piece of wood!
There are close to 7,500 breeding pairs in the British Isles and they survive almost entirely on carrion.
So there you have it; a resume of a fascinating and diverse family of birds. Some will cause concern to your conservation efforts, and some will damage your playing surface. However you tackle the problems they present, do please remember to stay within the law!
Crows, jackdaws and rooks are protected under the Wildlife & Countryside Act 1981 and the Wildlife (Northern Ireland) Order 1985. This makes it illegal to intentionally take, injure or kill them, or to take, damage or destroy an active nest or its contents. However, the law recognises that, in some circumstances, control may be necessary.
The UK Government issues annually a general licence (for which it is not necessary to apply individually) under the Wildlife and Countryside Act, which allows certain corvids to be killed or taken by 'authorised persons', using permitted methods, for the purposes of:
• preventing serious damage to agricultural crops or livestock
• preserving public health/air safety
• conserving wild birds
The killing can only be done under these specific conditions. An 'authorised person' is a landowner or occupier, or someone acting with the landowner's or occupier's permission.
Legal control methods involve trapping or shooting. Larsen traps, a type of cage trap, are designed to catch birds alive and unharmed, and it can be baited with food, or with a live decoy crow, jackdaw or rook (providing this decoy is provided with adequate food and water). If you suspect that a Larsen trap has been set illegally to catch birds of prey, please report this to the police Wildlife Crime Officer. Gun laws state that control by shooting can only be done well away from houses and public roads.
Many people wish to control crows and jackdaws in gardens, thinking that they are a threat to small garden birds. Considering that there is no scientific evidence that either species would pose a conservation problem to any species of garden bird, the RSPB believes that the use of general licence in this context is, at best, debatable. Where rooks choose to nest in suburban areas or in trees in gardens, people are often intolerant of their presence, either because of the noise, or because they have parked a car underneath the nesting trees and it has received the inevitable scattering of droppings.
These situations constitute a nuisance, which is not a legal reason to kill any bird or destroy its active nest. Occasionally, a large quantity of droppings may be viewed as a health hazard. It is advisable to obtain the opinion of a public health officer before any action is taken to ensure that the action is lawful.
In those situations where there is a genuine problem, deterrents that prevent the birds from settling to breed in the first place are far preferable to destroying nests. It must be remembered that, if challenged, anyone killing birds may have to prove to a court of law that they had acted lawfully.
If you require further guidance, contact Natural England for advice on dealing with wildlife management.
Wildlife LicensingNatural England
First Floor
Temple Quay House
2 The Square
Bristol
BS1 6DG
E: wildlife@naturalengland.org.uk
T: 0208 026 1089
Visit www.gov.uk for further information
• The term 'rookery' is also applied to other colonies of breeding animals, especially seabirds, but also seals, sea lions and some turtles. The term was also used to describe densely populated slum housing in nineteenth-century cities, especially London
• Crows living in suburban areas require only 10% of the nesting territory of those in rural locations. They are also much more tolerant of range overlap
• Some crows build fake nests to fool predators. This trait is not species specific
• Crows undertake 'anting' whereby they crush an ant and rub it all over themselves like perfume! The formic acid in the ants helps ward off parasites
• Crows like to sunbathe!
• Pet crows give their owners names. This is identified by a unique sound they make around specific people that they would not otherwise make
• Female Crows mate for life, but males will cheat, which explains the next one ...
• Male crows have no penis. Their sperm is transferred from their cloaca to the female cloaca and copulation only lasts fifteen seconds. It's a wonder the females are so loyal!
• Crows prefer French fries in a McDonald's bag over those in a brown paper bag, according to studies
Amenity grassland and the managed amenity sector lost the use of two key pesticides last year; suddenly and with very little warning. Two active ingredients - imidacloprid and chlorpyrifos - used generally for the treatment of chafer grubs and leatherjackets respectively, were withdrawn and no chemical alternatives are likely to be forthcoming.
These changes mean that there are no chemical methods for the control of chafers and leatherjackets in the UK amenity grassland and managed amenity turf sector.
There are alternatives, and these have been used effectively for over a decade. However, it requires a revolution in the way we think about pests in turf.
Cultural control
This constitutes removing thatch (un-degraded plant material) which is the foodstuff of both leatherjackets and chafer grubs. This can be done through a variety of means and each method will result in different volumes being removed over particular timescales: turf stripping will remove all of the organic matter, as will fraise mowing using a Koro Field Top Maker. Less forceful methods would be to increase aeration to encourage the organisms that are already present to degrade the thatch.
Biological control
Two methods can be employed: luring the adults away from key areas using pheromone traps, although this method is generally used as a monitoring tool to establish the size of the population and has a very limited capacity to affect a change on the population.
Alternatively, nematodes can be applied to treat infestations.
Nematodes
The group of nematodes that are used to control chafer grubs and leatherjackets are host specific. They are so host specific that different species of nematodes need to be used to control each of the two turf pests.
Each of the two nematode species used, Heterorhabditis bacteriophora for Chafer grubs and Steinernema feltiae for Leatherjackets, can be applied at the same time and won't disrupt each other. Both of these species are native to Britain, have been used effectively for many years, don't require any specific Personal Protective Equipment, are persistent in the soil for long-term control and are safe for users and the environment.
More information is available at www.pitchcare.com, or you can speak to one of our technical team on 01902 440275