The presence of gulls in urban areas has increased in recent years for a number of reasons such as the availability of good nest sites and discarded food.
Most of the gulls that live near us cause no problems to residents, however a small number are causing annoyance with noise, droppings and aggressive behaviour during the nesting season.
There are two species of gulls that are common in North Lanarkshire.
Large gull, reaching on average 55cm from bill to tail and a wingspan of 85cm when mature. They have silver/grey wings and pink legs.
Lesser black-backed gull
Slightly smaller than the herring gull, adult lesser black-backed gulls have slate-grey back and yellow legs.
Both species begin mating in April and start nest-building from early May onwards. In towns, the nest is constructed from straw and grass, twigs, paper and any other material the gull can conveniently use. The nest can be quite large, and, if made of heavy material accumulated over several years, very heavy.
Eggs are laid from early May onwards with two or three eggs being the usual number laid, in one clutch, per season. Eggs take around three weeks to hatch so the first chicks are generally seen about the beginning of June.
Seagull chicks grow quickly but generally do not leave the nest for five to six weeks and are quite active. They often fall from the nest and in town this will almost certainly mean they cannot return to the nest. Small chicks often die but larger chicks will be protected and fed by their parents on the ground. Parent birds protecting fallen chicks are often the ones that dive and swoop on people and animals who often do not realise a chick is on the ground.
Chicks tend to fly in late July and then take four years to reach maturity and breed.
Lesser black-backed and herring gulls tend to nest in colonies and once roof nesting birds gain footholds other gulls nest on nearby buildings. If left unchecked a colony can start to develop.
Gulls and the law
The main piece of legislation dealing with the control of birds including gulls is the Wildlife and Countryside Act 1981.
In general, it is illegal to capture, injure or destroy any wild bird or interfere with its nest or eggs. The penalties for disregarding the law can be severe. General Licenses, however, issued by the Scottish Government, allow measures to be taken against certain common species of birds on grounds that include the preservation of public health or public safety. Any action taken must be humane and the use of an inhumane method that could cause suffering would be illegal. The use of poisons or drugs to take or kill any bird is specifically prohibited except under very special circumstances and with a specific license issued by the Scottish Government.
The list of birds against which humane methods of control may be used includes Lesser Black-backed gulls and Herring Gulls. Only the owner of a building or the occupier can take action against the gulls on it, or they can give someone else permission to act on their behalf. Any work carried out must be reported annually to the Scottish Government.
In practice there are very few humane methods to kill gulls and skill and experience is needed to deploy them. The shooting of roof nesting gulls is not considered humane or safe.
Experts believe that a large-scale cull of gulls would not be effective. Indeed some believe that the gull population in the towns is different from that of local landfill sites and there is documented evidence to indicate this is the case. Culling all the gulls at landfill sites would not result in a reduction of gulls in the town and vice versa. Also, the practical aspect of carrying out a cull in an urban area is extremely difficult.
What can be done about gulls?
There are no laws that prevent people from feeding gulls, however, it is very undesirable to do this. Attracting gulls encourages them to foul the immediate area, causes disturbance from noise and encourages gulls to nest in areas they would otherwise not colonise. Gulls mainly forage in agricultural areas but will take discarded food in urban areas too.
Nests could be removed, however this would have to be repeated a number of times during the season as the gulls will rebuild their nest very quickly if it has been removed or destroyed.
Eggs could be removed from nests, however this would have to be repeated a number of times during the breeding season as they will be replaced once they are found not to viable by the parent birds.
The treatment of gull's eggs with liquid paraffin offers a cheap and efficient way of preventing hatching. If done correctly and at the right time of year, this technique is 100% effective in preventing the hatching of eggs but does not reduce the adult population.
Please note - culling and egg and nest removal are all measures that come within the scope of the general licenses issued by the Scottish Government and such action must therefore be justified.
Disturbance of birds
There are a variety of methods of disturbing or discouraging birds from particular locations including birds of prey or bird scarers. For areas within towns, none of these methods has yet proved successful in the long term.
Deny them nesting places
Controlling gulls is extremely difficult. The best method is to deny them nesting places on buildings. All owners/occupiers of buildings, which have or may attract roof-nesting gulls are strongly urged to provide the building with deterrent measures suitable to the individual building.
The main methods of deterrence are:
- Short spikes - there are several spiking systems commercially available that incorporate a stainless steel spike fitted in a plastic base. The spikes and base come as an assembled unit in convenient lengths, which can be cut to size. These spike systems may be useful for protecting small dormer roofs and other similar locations. The usual fixing method is to use screws or, where these would damage the structure, adhesives.
- Long spikes - these can be used to prevent gulls nesting on top of chimney stacks between the pots and in the valley behind a chimney stack where it meets the roof. Gulls sometimes nest behind chimney stacks where the chimney meets a sloping roof. The valley formed is often warm and sheltered from the wind and makes an ideal nest site. It is important to fix sufficient numbers of spikes to ensure that the nesting area is well covered.
- Wiring and netting - horizontal nets mounted sufficiently far above the surfaces to be protected and stretched tightly enough to keep them well out of contact with the roof even under the weight of several gulls landing on them may be effective. This method of proofing is however difficult and expensive as it has to withstand surprisingly strong and persistent efforts from the gulls to get through them.
Further advice and assistance
If you have a problem with birds nesting on large flat roofs you may wish to contact a specialist company for advice. Because of the problems of fixing any type of proofing we consider these methods should always be done by a competent specialist.