Want to see the largest carnivorous mammal in the UK? Think you may have to travel far to find it? Well, look no further than the Tees Barrage where we enjoy daily grey seal sightings and can even hear seals breathing from our office when the window’s open! Teesmouth is unique in Europe as the only estuary where an improvement in water quality has enabled seals to repopulate areas they once used in their hundreds. We have 2 native species of seal, the smaller common or harbour seal which breeds at Seal Sands in the summer and numbers around 120. However, the seal we see more commonly at the barrage is the larger grey seal, whose nearest breeding colonies are up at the Farne Islands or down on the Lincolnshire coast with the UK as a whole holding something like 40% of the global population.

copyright Peter Beesley 2012.

Every year, the Canal and River Trust (CRT) and the Industry Nature Conservation Association (INCA) join forces to coordinate a summer seal survey with volunteers at the barrage. This year, not only are the volunteers recording the behaviour, species and number of seals just downstream of the barrage but they’re also focussing on the navigation lock, from which we can hear the seals snorting and breathing through our office window. The information gathered is analysed and compiled in to a report by INCA who have been working hard with local industry for nearly 30 years to enhance their ecological capital and balance this with commercial needs and requirements. 

Make the most of the terns along the Tees this month as they will soon be gathering along the coast and heading south to leave the UK, bound for wintering grounds in Africa. However, on the flip side this change in the season also marks the return of our wading birds to our coastline, look out for groups of turnstone, sanderling and knot, some of which may still be in colourful breeding plumage as they arrive to spend the winter in milder climes. All are part of our new Coastal and Wading Birds project run in partnership with the Tees Valley Wildlife Trust; we’ll have more news about the launch of this project next month.

And finally, as the summer hits its stride, it’s interesting to see leaves on some of the horse chestnut trees along the Tees Valley are starting to turn brown from the bottom branches upwards, like a strange rising tide. This early autumnal effect is down to the Chestnut Miner Moth, an attractively marked micro moth whose caterpillars live inside the leaves, eating the green middle layer. First recorded in the UK in 2002, the moth has marched steadily north ever since and while the big appetite of the tiny caterpillars isn’t thought to cause the tree long term harm, a severe infestation can compromise the tree’s ability to photosynthesise. This year seems particularly bad for the moth, perhaps the mild winter enabled more than usual to survive in the leaf litter.