\u201cWe would therefore be concerned about any action taken to reduce productivity of the birds without reference to Natural England, the government\u2019s scientific adviser and wildlife regulator,\u201d the RSPB spokesperson said.<\/p>\n
There is also the question of efficacy: gulls would need to take the pill daily. But with scraps of discarded food widely available there is no guarantee the council\u2019s contraceptive-laced provisions would be favoured.<\/p>\n
\u201cSeagulls can eat many things,\u201d said Cecilia Soldatini, a senior scientist at La Paz University in Mexico, whose research focusses on seabird ecology. Her team uses cheesy fries to lure gulls, but the birds refuse fries that have become soggy in the rain.<\/p>\n
\u201cThey\u2019re not forced to eat what you\u2019re giving to them,\u201d said Soldatini, who has previously investigated the use of contraceptives in feral pigeons in Venice and found the approach to be of limited utility.<\/p>\n
Gulls also have a feeding range of 10-15km (6-9 miles), according to Soldatini, meaning they are not reliant on resources from a tightly defined area. The key, she said, was to eliminate the resources attracting gulls in the first place. \u201cDon\u2019t make food available to them, work on the collection of rubbish. This is the only way.\u201d<\/p>\n
Dr Giovanna Massei of the University of York, who is Europe director of the Botstiber Institute for Wildlife Fertility Control, said that \u201chard scientific evidence\u201d should be sought before any rollout \u2013 research she said councils ought to fund if they wished to explore this option. \u201cIf you put something out and then there are lots of fish and chips lying around it\u2019s difficult for [the gulls] to get the dose they need.\u201d<\/p>\n
She added: \u201cI understand that some councils are desperate to find a solution.\u201d<\/p>\n
Kay Haw, the director of UK Squirrel Accord (UKSA), said injectable contraceptives had been used successfully in herd species, such as wild horses in the US. UKSA is investigating oral squirrel contraceptives jointly with the government\u2019s Animal and Plant Health Agency. \u201cThere are about 3 million grey squirrels in the UK,\u201d she said. \u201cYou can\u2019t catch them all and inject them.\u201d<\/p>\n
However, extensive research and fieldwork has had to be carried out over several years before the planned distribution of medicated food can proceed. \u201cIt\u2019s not a quick process,\u201d she said.<\/p>\n
A key requirement is ensuring the contraceptives only get to the target species \u2013 in this case through a special feeding device that red squirrels are unable to operate. Haw said the protein-based contraceptive being used breaks down so quickly that a predator would have to \u201ceat 1,000 squirrels\u201d to be affected.<\/p>\n
\u201cPeople aren\u2019t necessarily as careful as they need to be about this,\u201d she said. \u201cThey have issues on the Isle of Wight with red squirrels being poisoned by rat poison.\u201d<\/p>\n
Soldatini agreed that non-eaten food could pose an environmental risk. \u201cIf it rains, it can go into rivers, or seawater,\u201d she said. \u201cThis same pills can affect the populations living there \u2013 fish, other birds, sea mammals.\u201d<\/p>\n
The squirrel project also has a different motivation: to support the growth of red squirrel populations and the health of woodlands, not simply to remove a species deemed to be a nuisance to humans. \u201cWe\u2019re working on an invasive species problem \u2013 the [grey squirrels] should never have been here,\u201d Haw said. \u201cThat\u2019s a different angle to a native species.\u201d<\/p>\n
A Worcester city council spokesperson said: \u201cAn annual gull report will be presented to the city council\u2019s environment committee on 5 November. This will provide councillors with an opportunity to consider a gull management programme for 2025.\u201d<\/p>\n