The comparisons with an Exocet missile are easy to see; streamlined, a pointy end, and likely not a good outcome for what it’s about to come in contact with.
The nerd in me has a problem with this however. As well as being into birds in a big way during the 1980s, I was also fascinated by the Cold War. So, I know that an Exocet missile flies along the sea surface towards its target whilst the bird we often compare it to, the gannet, dives at a sharp angle in pursuit of its prey.
During the autumn, Scapa Bay has become something of a training ground for young gannets making their way in the world. Scapa beach lies at the northern end of Scapa Flow and is probably the most visited beach in Orkney given its proximity to Kirkwall. I often walk my dog here but I’ve long had a relationship with this area.
My dad was a skipper on one of the tugs at Scapa pier, manoeuvring oil-carrying giants in Scapa Flow during the 80s and 90s. I would cycle from Kirkwall to visit him when the ships were alongside and double it up with some birdwatching at the same time. Scapa beach became my local patch and I would count wader numbers after school and do core samples in the sand to see what the birds were after.
One of my most vivid birdwatching memories took place here, although as far as stories go it doesn’t have much to it! I had watched a small flock of knot for around a week and then noticed an orange bird amongst the grey ones. It was of course still a knot, but in its summer plumage, and I was totally delighted. It was just one of those small moments of joy often found in different but simple things.
Whether groups of young gannets have always spent time in this bay during the autumn I can’t remember, but they wouldn’t be here if there wasn’t fish to prey upon. Around four years ago I saw a similar thing happening. The water held huge dark patches with large flocks of gulls plunging as best they could to get underwater, occasionally coming up with a small writhing silver fish.
I got in the sea that day with a GoPro to see what all the fuss was about and the end result was a short film for BBC Autumnwatch. ‘Shimmers of the Shoal’ was a 90 second piece for the ‘mindful moment’ slot that was born out of the Covid lockdown where it was evident people needed to rest their minds, to be taken away somewhere other than their living room.
I assumed like many other folk that these were herring but local naturalist, Martin Gray, suggested doing a test of sorts if it were possible to get a hold of a fish somehow. At around four to five inches long with a large eye and silver body, it turns out that herring and sprat are superficially very similar - could these be sprats and how would I ever tell the difference? Herring and sprats do also mix sometimes, how inconvenient for me!
I noticed as I swam amongst them that a few were injured with either a piece of fin missing or a small chunk of flesh, presumably a close call with the many predators currently after them. Some weren’t so lucky however, with a few dead ones floating on the surface, one of which I collected and took home to examine.
There can be subtle differences in eye size and fin positions between the two species but one good way to tell the difference is to rub its belly. If you run your finger from the tail fin of the fish all the way to the gills you will find the answer. If the soft belly is smooth to the touch, then it’s a herring, if your finger catches on the tiniest of spikes it is a sprat. My finger is interrupted along the way, not sharp enough to be painful but the barbs stiff enough to be noticed. Sprat it is then.
These young gannets couldn’t care less if they were herring or sprats, they just want them in their bellies regardless. There aren’t enough birds here to warrant calling this a spectacle but does there really need to be? As I watch them diving into the sea it’s a moment of wonder and can’t help feeling that what they are doing now will hold them in good stead when they have to leave the bay and face the often-cruel conditions of an Orcadian winter, though most likely leave for the slightly warmer climes of the Bay of Biscay and beyond.
There are perhaps twenty juvenile gannets here along with a handful of guillemots and two pairs of watchful eyes - the selkies know there’s an opportunity here too. These young birds seem to be taking incredible risks in pursuit of the sprats, diving very close to both the pilot boats and the pier itself. There doesn’t seem to be a one size fits all approach to the dive either. Some take off from the surface of the sea and fly in a wide arc, flying relatively high, then dive towards the surface at a 45-degree angle.
This is a 10/10 dive with the resulting impact making an incredible noise, a crumpling thumping thwack of sorts. Others take-off then realise there are fish nearby, they are barely a metre off the surface but decide to go for it. They still manage to completely fold their wings before the lunge forward but this is all it is, a lunge and they don’t completely submerge as a result.
The high divers however certainly make it below the surface and as I watch them from the pier you can see the stream of bubbles they create as they break the surface. The noise suggest they hit the water with some speed but they have perfect adaptations to cope with the force.
Gannets have a reinforced skull and adapted neck muscles to help absorb the impact. They plunge straight into shoals just below the surface but bob back to the surf like a cork, almost popping right out of the water again.
As addictive as it is watching them, my curiosity gets the better of me and I want to get below the surface. Another assumption is that these shoals have been driven here somehow, either by mackerel or perhaps even just by geography - there is nowhere else to go after all if you have made it this far north in Scapa Flow.
I don my wetsuit, clear my mask and tighten the straps on my fins. The cold water bites the exposed skin of my cheeks as I swim the short distant before seeing the fish. The first thing I notice is the visibility isn’t nearly as good as the last time I was in here. The gloomy nature of the water however means that the rays filtering down from the southern sky are more prominent and the silver backs of the fish light up as they swim underneath them.
Just as those two pairs of eyes watched me from the surface, those same eyes watch me now. Two grey seals glide past at the edge of my visibility and the sprat react in a way common to shoaling fish that feel threatened by a predator, they create a bait ball.
The disconcerting thing for me, although I know what’s happening because they did this four years ago, is that fish often create their bait ball around the predator. With the seals on one side and me on the other they rush around me until my own visibility is compromised. I fully expect to come face to face with one of the seals pushing them my way. The wind isn’t very strong but it’s enough to push me out a little further where I can see that the sea bottom drops off with a little shelf, certainly deep enough for a diving gannet. They might hit the water at breakneck speed but they won’t be breaking their necks here.
I hear a loud ‘thump’ and see that there is a pair of broad webbed feet heading in my direction, a gannet must have dived nearby. Unlike adult gannets which have startlingly white feathers and a yellowish head, these first-year birds are chocolate brown with many white flecks that sometimes give them a silver appearance in the right light.
I can’t help wondering which local colony they came from before finding this fish-filled training ground. Westray, Marwick Head, Sule Stack or Sule Skerry? Hopefully the fish find their way in here next year too, followed by the solan goose, and this becomes a regular spectacle within Orkney’s natural calendar.
Raymond is a wildlife filmmaker who also offers bespoke Orkney wildlife tours and one-to-one wildlife photography tuition. Find out more via his official website. You can also find him on Facebook, Twitter and Instagram.