of flora and fauna are found on campus, including many rare trees that date back to the days of the FRI. The school has over 150 species of trees on its campus, and the formal gardens attract a variety of birds. The school is listed as a hotspot on the eBird database of Cornell Lab of Ornithology, and 130 bird species had been identified on the campus as of June 2021. In the 1940-50s, ornithologist Salim Ali, who was a friend of Foot, Gibson and Martyn, was a regular visitor to the school; he sensitized generations of pupils to the natural diversity of the school campus, and introduced them to many aspects of ornithology. In 1996, a book titled Trees of Chandbagh was released which provided a comprehensive account of vegetation found on Doon's campus. Along similar lines, the illustrated book Birds of Chandbagh: A Guide To Birding at The Doon School was released in 2019, featuring photographs, illustrations and QR codes documenting the bird calls of the species found on campus. The school has devised an Architectural and Projects Committee, which ensures that any construction taking place on campus is done without disturbing the ecological balance of the wooded school grounds. Curriculum The school practices a five-and-a-half-day week consisting of 40 periods (or "schools"), each of 40 minutes. The school day begins with boys having chhota haazri before doing calisthenics outdoors on the playing fields, which is then followed by classes. On Sundays, boys are free to pursue any activity or sport. Senior boys may go into the town for leisure on designated Sundays, after taking permission from the housemaster of their respective houses. The student-teacher ratio at the school is 10:1. Doon pupils take the International General Certificate of Secondary Education (IGCSE) exams in tenth grade, which replaced Indian Certificate of Secondary Education in 2017, and are thereafter offered two strands for the final two years: International Baccalaureate (IB) or Indian School Certificate (ISC). The academic year has three terms: spring, summer and autumn. The autumn term runs from August to the year-end final examinations in November, after which the boys are promoted to the new class in February. Each term has a "test week" and end-of-term examinations known as "trials". Boys are able to visit teachers, most of whom live on campus, for further academic help. Additionally, each boy is assigned a 'Tutor' – a School Master