In the final programme Colin heads to Mayo in search of the elusive otter, goes moth-catching and meets some budding wildlife enthusiasts.
In Kilkenny, Colin heads up river, and then home to Mayo in search of the elusive otter, finally tracking two parents and their cubs who have made their home on the rocks around Westport quay.
Later he meets up with a surprisingly enthusiastic group of moth-catchers, then watches them concoct smelly, sticky potions, erect nets and light boxes to attract the rarest of Ireland's many thousands of moth species.
Enlisting for a course on seashore life, Colin meets a group of national schoolteachers turned wildlife students. Then - in the company of teacher, Eileen O'Malley and her class - Colin discovers the secrets of successful marine biology: a bucket, a spade and a net.