
Seagull populations are extremely successful in urban
environments and nuisance populations continue to grow in
metropolitan areas. A combination of factors work in their favour:
A) Human waste (food litter) provides and excellent food source.
B) Buildings providing safe nesting environments away from natural
predators.
With seagull populations increasing at around 13%, numbers of these supreme opportunists are set to skyrocket in future years. Breeding success also means expansion into other urban areas. Besides general noise and annoyance (including injury caused by the birds dive bombing during the breeding breeding season), bird droppings carry many diseases transmissible to humans, including thrush, E. coli and salmonella poisoning. Seagulls also carry a range of ecto-parasites (including bed-bugs, fleas and ticks) and these are also known to affect humans. A new approach to the management of nuisance urban gull populations lies in the reduction of their local breeding success using imitation eggs. The breeding season runs from March to the end of July. Blatant removal of nests or smashing of eggs simply results in the gulls re-laying. Research has shown that sterilisation of the eggs by oiling encourages the adults to incubate the eggs for longer than the usual 28-30 days. After this time the pair abandon the breeding attempt due to egg decay and potentially relaying elsewhere. Whilst the parent birds are sitting on the nest they remain muted. Seagulls are notoriously noisy and aggressive when chicks hatch. A recent study has shown that urban seagulls will also accept plastic replica eggs in place of their own in the nest. Moreover, the results are more successful than when the eggs are sterilised as they do not decay. With plastic eggs, the seagulls incubate and remain quiet for the full season, leaving the nest only when the fake breeding period is over in August. This method also has the added advantage that the process is less fiddly and the fake eggs reusable in the following year. As well as keeping breeding seagulls calm, repeated replacement of real eggs with non-viable imitations each season reduces the number of hatchings and thus the number of future breeding birds. seagull populations decline in the long term, in an environmentally and humane manner.
