Night life of the black lakes by Mark Hancock (Senior Conservation Scientist)
Forsinard reserve and the Flows of northern Scotland are famous for their 'dubh lochs' - literally 'black lakes': so named because their water is naturally stained by the peat, to be the colour of strong tea. As part of our research work at some of these lochs, we've been setting up camera traps - cameras that automatically take a photo when wildlife passes by.
Later in the spring, here in the far north, the nights will be short and barely even dark. But for now, there are still several hours of darkness. The camera trap images are always intriguing - but especially so for the night-time shots.
Birds that we are familiar with from our daytime visits to these lochs, turn out to be less diurnal than we might suppose. Here's a stealthy heron, nicely reflected on a calm night, just after 3.30am....
A few days later, a greenshank - quite a common bird at these lochs - walks into view, just after nine at night (look carefully at the right hand side of the shot)...
Occasionally we get lucky and the camera captures otters passing by...
There were also a few nice night-time shots last season, like these two stags...
And this unfamiliar view of a male mallard, out and about at 3am...
It's interesting to see, for different species, how the pattern of records varies during the 24 hours. One of the commonest waterbirds on these lochs is the teal - which seems to be mostly active during the daylight hours:
Meanwhile Mallards seem to crop up more evenly throughout the 24-hour period:
Perhaps Mallards, being so much bigger than Teal, are less affected by the cold nights of this area? Or maybe they are feeding on a different food source, which doesn't vary much in availability during the 24-hour cycle? Or perhaps they are less dependent on sight for foraging, relying more on touch?
Herons show a clear evening peak in their activity at these lochs:
Perhaps they have learnt this is the best time to capture fish or other prey in the shallow water at our lochs.
Beautiful as these northern lochs can be in the evenings and early mornings, the darkest part of the night is always something of a mystery. So it's great to have a helping hand from technology. As long as we keep them topped up with fresh batteries and memory cards, the camera traps will sit patiently, night after night, waiting for something to walk or swim past.