Animals are essential in maintaining ecosystem balance, but in some cases they can have the opposite effect. In the coastal city of Mombasa, Kenya, authorities are looking to cull 1 million Indian house crows. Conservationists say they are becoming a nuisance and have significantly reduced the number of small indigenous birds in the region. So how will they be dealt with? The BBC’s Dorcas Wangira, an Africa health correspondent, explains.

Pest are an issue in New York too. There’s estimated to be 3 million rats scurrying around the Big Apple and the city’s mayor has made it his mission to deal with the rocketing number of rodents by hiring a ‘rat tsar’. Sam Cabral, a BBC reporter in New York, tells us more.

Finally, we hear from Predator Free Wellington, an organisation in New Zealand, which is hoping to completely remove predators (like rats and possums) by 2050.

Instagram: @bbcwhatintheworld WhatsApp: +44 0330 12 33 22 6 Email: whatintheworld@bbc.co.uk Presenter: Alex Rhodes Producers: Mora Morrison and Baldeep Chahal Editor: Emily Horler