We’ve lived in York since 2004 and this is the first time I’ve seen these birds. They are classified as being nomadic when it comes to habitat which obviously means they move around as conditions dictate. Both require aquatic invertebrates to feed off which means that the river is in a healthy state. As I’ve said  before in previous posts the Avon largely dries up over summer leaving a series of deep pools and  In the past at this time of year they tend to be stagnant, have algal blooms and stink. This year they have largely been free of algae, don’t smell and the larger ones are full of small fish, dragonfly and damsel fly nymphs which are all indicators of a healthy river. The arrival of the Black-fronted Dotterels and Black-winged Stilts confirms this.