The Solihull Council department responsible for landscaping, wildlife management and conservation reported yesterday that otter "spraint" - the technical term for droppings - had been photographed at Cole Bank Park Local Nature Reserve on Friday.
The signs of activity at the site - which was the focus of a habitat improvement project in 2016 - are hugely encouraging for conservationists.
Otter populations across the UK had crashed between the 1950s and 1970s following intense persecution of the species and large quantities of pesticides washing into the nation's waterways.
In recent years there have been concerted efforts to clean up rivers, canals and other watercourses to encourage the elusive mammals back into areas where they had either vanished or been pushed to the brink of extinction.
The West Midlands, in common with many parts of the country, has seen an increase in otter numbers. A report for the Environment Agency in 2010 suggested there had been a ten-fold increase in positive sightings over the course of 30 years.