Country diary Shetland

My head is filled with unforgettable images of killer whales. Nearby is an offshore rock that is a favourite haul-out for seals - prey for killer whales. That day the rock was abandoned and the seals were in the shallows, hoping these would afford some protection. Upright in the water, heads held as high as possible, they appeared like marine meerkats in their hyper-vigilance.

I think all of us watching gasped aloud when, from the centre of a flurry of water, the small, dark body of a seal was flung spinning through the air. Where it landed there was a commotion of water; the surface seemed to muddy briefly and then bloomed red. Its kill swiftly and efficiently made, the whale resumed circling, while gulls swooped, quarrelling over surface scraps.

The menace of that dorsal fin slicing through the water as the whale maintained its relentless patrolling! The readily available speed as it occasionally heeled into an accelerated turn! The aura of power did not diminish on its rare forays along the coast - the fin was easily visible half a mile away.

Two days later a pod including a calf turned up in exactly the same place. Down on the rocky foreshore we stood in warm sunshine watching them hunt as a group. The blows of their breathing clearly audible, bodies gleaming in the sun, they constantly passed within yards of the spellbound observers, patient, effortless cruising and circling suddenly culminating in an explosion of power and swift motion as a kill was made. Later from the cliff top we watched with awe as they sped, tight-grouped, across the bay, sunlight casting colours through the fine mist of their blows. Intriguingly, it seems the group's arrival may not have been coincidence. The Scottish Killer Whale Project identifies and records orcas, naming them for the place they are first seen. Recognised by his notched dorsal fin, our first visitor was Bigga, who habitually travels alone. He is known to associate with a family group known as the Eynhallow 5 - the group who turned up just two days after he did.