Madrid’s city council is preparing a plan to clear the city of its pesky parrots – which will include the “ethical slaughter” of the birds and and sterilization of eggs, authorities said Monday. Argentine parrots – myiopsitta monachus, also known as monk parakeets – are native to South America, but many were kept as pets in Spain before ownership became illegal in 2011. Many of the parrots escaped, or were released from captivity, and are now prolific in Madrid, as well as number of other areas in Spain. The population of Argentine parrots in Madrid’s parks has risen by 33% in three years, from 9000 in 2016, to 12,000 already accounted for in 2019, according to data from the Spanish Society of Ornithology. In 2005, there were an estimated 1,700 of the birds in Madrid. As the population grows, so do the problems. The birds, considered an invasive species in Spain, are noisy, messy, and are certainly ruffling the feathers of local residents, who have already filed 197 complaints about the birds this year, and 209 in 2018. “We are going to put in motion a plan for the control and reduction of parakeets in the city of Madrid, as they have become a concern for the citizens and we have received a lot of complaints,” said Borja Carabante, Madrid’s Environment and Mobility delegate, in a statement. The birds also build nests which can reach up to 200 kilograms (441 lb), which could pose a threat to Madrid’s citizens if they were to fall, authorities said. The parakeets are also thought to threaten biodiversity in the city by competing for food, and damaging vegetation while building their nests. Though no cases have been confirmed, the council warned that the birds could pose a danger to human health, as they could transmit bird flu, salmonella poisoning or psittacosis (parrot fever). Santiago Soria, head of the council’s Biodiversity and Inventory Service, said that the objective was not to eliminate the whole parrot population, but explained that without intervention it would continue to grow. “The spirit of the law is to do no damage to our wildlife,” Soria told media. Madrid is not the only Spanish city with bird problems – the southern cities of Malaga and Seville have both proposed measures to cull their parakeet populations. But such moves have been met with strong opposition from animal rights groups, who argue that numbers can be controlled through non-lethal methods such as contraception. in 2018, local authorities in the the southwestern port city of Cádiz concocted a plan to capture and relocate some 5000 pigeons who were bothering local residents.