Several
species of gulls (Larus spp.) have colonised urban
areas across the country during the last decades.
A British research project showed that the urban Gull
population has a growth rate of 13% a year, which
equals 30 new gulls per breeding pair in 10 years.
| Gulls
are supreme opportunists and readily adjust
to new sources of food and breeding grounds.
They are capable of making round trips of more
than 100 km in a few hours while searching for
food. The flat roofs of many commercial buildings
provide near perfect nest sites: spacious flat
surfaces, water from air conditioning units,
shade from roof top structures, available food
from dumpsters etc, and very little disturbance,
no non-flying predators and higher temperatures
than in the surrounding landscape which allow
for earlier breeding.
The nest is
simple usually consisting of material found
on the roof that has been scraped into a low
pile. Gulls in their “natural” environment
are migratory but urban gulls often display
non-migratory behaviour due to the hospitable
urban environment.
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Gull abundance in urban areas cause
numerous problems to building owners: Feathers and
nesting material clog drains on rooftops causing flooding,
damage from defecation on roof material and awnings,
damage to air conditioning units and other roof top
machinery and generally making a mess of the buildings
they roost and nest on. During chick rearing access
to roof top machinery is often impaired due to the
aggressive behaviour of breeding birds. To the general
public aggressive and noisy behaviour, hazards to
air traffic and transmission of diseases and parasites
through contamination of water sources is of concern.
In New York in 1993 several hundred people came down
with a mysterious illness. It was traced to sea gull
droppings in a city reservoir.
Gull abundance in urban areas cause
numerous problems to building owners,
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Feathers
and nesting material clog drains on rooftops
causing flooding and prevent efficient drainage
of the water which can lead to premature aging
of the roof membrane. |
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The
damage from feces accumulating on the roof material
has been proven to shorten the life expectancy
of the roofing material. |
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Risk
to indoor air quality can occur from nesting
activity in and around o air conditioning units
and other roof top machinery. During chick rearing
period of the breeding cycle safe access to
roof top machinery is often limited due to the
aggressive behaviour of breeding bird. |
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Transmission
of diseases and parasites through contamination
of water sources is possible as happened in
New York in 1993, several hundred people came
down with a mysterious illness. It was traced
to sea gull droppings in a city reservoir. |
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Gulls
often feed in large flocks, aircraft movements
can be dangerous when gulls have flocked to
feed on such things as earth worms on wet runways
after a rainfall. |
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