Kingfisher (Alcedo atthis)
Healthy fish populations mean that a reasonably common sight on the Wye and Usk is an iridescent blue flash of a kingfisher as it flies fast and low over the water, its short wings giving off a whirring sound as they beat rapidly.
Kingfishers are highly territorial. They must eat around 60% of their body weight each day so it is essential to have control of a suitable stretch of river. They are solitary for most of the year, roosting alone in heavy cover. If another kingfisher enters its territory, both birds display from perches, and fights may occur, with the birds trying to grab each other's beak to hold it under water. Pairs form in the autumn but each bird retains a separate territory, consisting of around 1⁄2 to 2 miles of river.
They hunt prey from riverside perches, occasionally hovering above the water's surface. Their diet mainly consists of the small fish that are abundant in the Wye and Usk, such as minnows and the large shoals of fry (juveniles) of a number of other species. However, they are a vulnerable to hard winters and habitat degradation through pollution or unsympathetic management of watercourses and currently have an unfavourable conservation status in Europe.