Public participation is critical for planning and management of protected areas. With people increasingly using social media, including Twitter, to obtain news and express opinions, park agencies should recognize the utility of monitoring and engaging with this public discourse. We used a conservation culturomics approach to analyse Tweets during a period of controversy about the management of large mammals (horses) in a park (Kosciuszko National Park in Australia), including examining who talked about what, when and what emotions were expressed. An automated programming interface was used to collect metadata for Tweets about the Park, with keywords coded while sentiments and emotions were analysed using a standard lexicon of terms. The debate over introduced wild/feral horses in the Park dominated the discourse, accounting for 56% of the 2085 Tweets referring by name to the Park over 275 days. Many Tweets referred to horses (44.8%) and/or used the alternative term, brumbies (15%). They were more likely to be Retweets, be sent by Australians, with a potential reach of over 5 million followers. Peaks in Tweets related to specific events in the news, with Tweets sent by journalists and others in a professional capacity or specific organisations engaged in the debate more likely to be retweeted. Despite considerable polarisation in the broader debate, including in the traditional media and on other social media platforms, the discourse on Twitter focused mainly on the environmental impacts of horses, and ways to reduce their numbers, rather than wanting to keep horses in the Park. There are important issues with the use of Twitter data including challenges in identifying relevant Tweets, biases in who Tweets and what is retweeted, limited text in Tweets, and increasing focus of the rights to privacy online. Twitter, however, remains a relatively fast, timely and often free way to listen into public debate with a large potential audience, is simple to analyse and hence provides valuable insights into public reactions to park management decisions complementing other data sources.