Roof Nesting Seagulls


There are several species of gulls that can be seen locally and to many people they are all just “seagulls”, the Lesser Black-backed and Herring Gulls commonly nest on buildings.

Roof nesting by gulls is a fairly recent phenomenon. It should however be noted that occasionally other birds that might be mistaken for Lesser Black-backed and Herring Gulls.

These other “roof nesters” are discussed in the section The Law

Typical Problems

Many people who have gulls on their property find they cause a nuisance. Commonly cited problems

Noise, caused by calling gulls and by their heavy footsteps.

Mess caused by their droppings, fouling of washing, gardens and people.

Damage to Property

The birds can dive and swoop on people and pets. This usually occurs when chicks have fallen from the nest and adult birds attempt to prevent them coming to harm by frightening away potential threats.

Blockage of gas flues by nesting materials can have serious consequences if gas fumes are
prevented from venting properly.

Life Cycle

Lesser Black-backed Gull Herring Gull

The identification of these two large, white-headed species is straight-forward in adult plumages. They all show white heads, underparts and tails and have yellow bills, however:

Herring Gulls show a silver-grey mantle and pink legs. Lesser Black-backed Gulls show a slate-grey mantle and yellow legs.

The species-split in Cardiff is thought to be over 5:1 in favour of Lesser Black-backed Gulls.

Gulls are large birds. They are, in fact, about 55 cm (22″) from bill to tail with a wingspan of about 85 cm (34″).

Breeding pairs court in March and commence nest building from early April 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 material accumulated over several years, very heavy.

Eggs are laid from April to May onwards with two or three being the usual number. The eggs take about three to four weeks to hatch so the first chicks are generally seen about the beginning of June.

The chicks grow quickly and are quite active and often fall from the nest. In towns this almost certainly means they cannot return to the nest. Small chicks will die unless returned but larger chicks
will be protected and fed by their parents on the ground. Parent birds protecting fallen chicks are the ones which dive and swoop on people and animals, who often do not know the chick is down on the ground.

Chicks generally fledge in August and then take three or four years to reach maturity and breed. The life expectancy of a Gull which reaches maturity is about 20 years.

Gulls will tend to return to the same nesting site and unless action is taken to proof a building, problems associated with these birds may recur annually.

Know Your Gulls

Whilst the gulls which nest on buildings are usually Lesser Black-backed and Herring Gulls, there are several other gull species which occasionally nest on buildings. The following species are examples:

Much smaller than Herring gulls and more delicate, they usually nest on steep cliffs. Occasionally, however, they nest in colonies on building ledges.

Slightly smaller than a Herring gull, wings look very stiff and straight in flight. Nest occasionally on fronts of large buildings overlooking the sea. Although Fulmars look like gulls they in fact belong to a different bird family. Kittiwakes and Fulmars are fully protected under the law. Anyone interfering with them, their nests or eggs could be committing a criminal offence.

If you have any doubts about what kind of “gull” is nesting on your property, please ask someone who knows. Our own staff are able to offer assistance if required.

What Can I Do?

The best time to undertake any deterrent work is outside of the nesting season. (see life cycle above)

All owners/occupiers of buildings that have, or may attract, roof nesting Gulls are strongly urged to provide the building with deterrent measures suitable to the individual building. The principal methods of deterrence are:

Fitting of bird spikes to nesting locations such as chimney stacks.

Fitting of short spikes, contained in a special plastic base, to nesting locations such as dormer rooves.

Fitting of bird wire or bird netting to prevent Gulls landing.

Because of the problems of fixing and the danger of trapping birds in or under nets, consideration of these methods should always be done by, or after having taken advice, from a competent specialist.

You may wish to ask Falconry Services to offer advice on bird proofing.

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