FOLLOWING an extended spell of extremely hot and dry weather, the possible negative effects of low river levels on wildlife have been discussed in the media (e.g., www.bbc.co.uk/news/science-environment-62465805 ). Concern was expressed that vital resources were ‘drying up’, with extremely low water levels reducing the viable environment for some species, making it difficult for them to find food and survive. At one place, along the river Mole, in Surrey, the situation was so extreme that fish had to be relocated by the Environment Agency (https://m.youtube.com/watch?v=YQey4b6Uqb4 ).

One iconic species that I think may struggle when the river level is low is the otter. I have often thought that otters are much less likely to be seen along the Wharfe, near Ilkley, in these conditions. Perhaps this is because it is much more difficult for them to pursue fish in shallow water. Perhaps it is because the shallow water leaves otters much more exposed to people and dogs. It seems consistent with the literature that, at times like these, Otters look for places where there is deeper water, and they also become more nocturnal in their activities. Otters typically have ranges that extend over some miles, so hopefully they have some good options and their absence is just temporary.

However, for low-nesting waterbirds, such as Moorhens, absence of otters during the breeding season is a blessing. Both adults and their offspring would feel more secure if otters are not around. Generally, waterbirds show Otters a healthy degree of respect, and rightly so. Although the diet of river Otters primarily consists of fish, perhaps supplemented with crayfish, they are eclectic and practical in their food choices. If a preferred source is in short supply, or difficult to catch, they will look elsewhere, and waterbirds can feature on the menu.

Recently, I was at an RSPB reserve in Norfolk, when this character (see photograph) popped into view in a small shallow pool adjacent to a large area of reedbed. After a couple of short dips below the surface, it headed for a section of reeds where it was out of sight. Suddenly, perhaps a dozen waterbirds exploded from the vegetation before settling at the other end of the pool. They looked distinctly rattled, and stared long and hard at the place they had just left. I had no way of telling whether there used to be a dozen plus one waterbirds before the otter’s intervention - but, in any event, it had certainly given them a fright.