Five years ago, the only bird Emily Kwan Wing-lam could recognise was a sparrow. But now, when a spotted dove appears outside her classroom, she can name it, and tell her classmates all about it.
Kwan, who will turn 13 next month, is one of the youngest volunteers at the Hong Kong Wetland Park in Tin Shui Wai.
'It's an interesting experience,' she said. 'I can learn more about wetland insects and animals, and at the same time, share my knowledge with the others.'
While he is more than half a century older than Wing-lam, the park's oldest volunteer, Ho Keung, volunteers for much the same reason.
'I like watching birds, but in the past, I knew very little about them,' the 70-year-old said. 'Now I can recognise more than 40 species.'
The pair are among the park's 1,000 active volunteers. They guide tourists, take care of the wetland habitat and hold workshops for visitors.
Sam Cheung Chi-kin, a supervisor at the Agriculture, Fisheries and Conservation Department, who is in charge of the volunteer programme, said more than 7,000 people had registered as volunteers since the first stage of the park opened 10 years ago.
Applicants for the programme must attend a three-day training course teaching them the basic facts about the wetland, work as volunteers for 12 hours and pass a test to qualify. More in-depth courses in specific fields are also held from time to time for interested volunteers.
Ho, who retired from his job as a construction consultant last year, was one of the first volunteers at the park and one of the few who has worked there since it opened. He planted some of the trees there.
Ho, who spends much of his time looking after his two grandchildren, says seeing the reaction of visitors is the most interesting part of his volunteering work.
Ho enjoys hiking with fellow volunteers in his spare time and says he still comes across many bird species he cannot identify. 'The more time I spend with nature, the more I realise how little I know.'
Wing-lam said the volunteering experience had helped with her studies. Her mother, Luk Yin-ping, said it had helped her daughter to make new friends.
'It improves her memory and allows her to meet more people,' Luk said. 'Now some of her classmates say they want to join too.'