Watching bottlenoses and dinky minkes

Another Life: The sad saga of the whale in the Thames drew me to BBC 24 just in time to hear the straying animal named as a pilot whale. Before it disappeared under the next bridge, enough of its shape had registered for me to guess at something even more unlikely - a northern bottlenose whale.

Along with the later fillip of having a wild hunch confirmed came a rush of admiration for the Irish Whale and Dolphin Group (IWDG) - how well they have opened our eyes! In the 16 years since the group began, led by young zoologists at UCC (Simon Berrow and Emer Rogan), it has launched Irish natural history on a wonderful new chapter of discovery and research. Almost as if conjured up by sheer enthusiasm (and notably by the tireless eye of Padraig Whooley, now the group's secretary and sightings coordinator), big whales began suddenly to materialise at binocular distance off the headlands and islands of Co Cork.

Scenes familiar only from wildlife films about the North American coast are now enacted in the waters off Bantry Bay, Cape Clear, the Old Head of Kinsale, Ardmore Head - leaping humpback whales, processions of fin whales (second-largest mammal in the world) and their dinky minke cousins, not to mention the acrobatics of several sorts of dolphin. Had all this been there all the time? With some allowance for the slow ebbs and flows of ocean life, the answer must be yes, but it had to be watched for, with constant effort and belief.

By a coincidence, the winter newsletter of the IWDG has a great deal to say about the northern bottlenose whale, Hyperooden ampullatus. Because the wanderings of this beaked and bulbous-headed mammal, supposedly happiest in Atlantic gullies more than 1,000 metres deep, have not been confined to the Thames. As Padraig Whooley reports, two of the whales came nudging into the shallows of the Cork coast last August.

The first one, an adult female some six metres long, followed the Swansea-to-Cork MV Superferry into Ringaskiddy Pier, where, trickling some blood, it floundered alongside the ship, among car-bumpers and assorted port debris. "With every passing hour it grew increasingly lethargic as it wallowed in an unhealthy, toxic mix," as Whooley described, and by morning it had died.

His second encounter, a week later, was a redeeming experience. The whale was swimming in Pulleen Harbour on the Beara Peninsula, diving at regular intervals and sometimes staging energetic bouts of fluke slapping and breaching. It stayed for a week in the harbour, where its clifftop audience numbered "hardened fishermen side by side with Buddhists." The instructive IWDG website (www.iwdg.ie) shows only five validated sightings of this whale in Irish waters, all clustered around west Cork - where, of course, most watching effort is concentrated. Like most beaked whales, its main diet is deep-water squid, which only deepens the mystery of its inshore and upriver behaviour. But the Cork encounters do lend an interesting perspective to the wanderer in the Thames and to conjectures that the whale had been disoriented by naval sonar. This has been linked to some 30 strandings and deaths of whales around the world and seems especially harmful to the beaked species. The disappearance from the Bahamas of Cuvier's whale, closely similar to the northern bottlenose, has been blamed on US naval exercises in the area.

Along with the regular and majestic winter progress of fin whales, the sporadic appearance of humpbacks off the Cork coast suggests that south-western Ireland provides something of a way-station on migration routes between breeding and wintering grounds. A recent match between a humpback photographed off Iceland and another off Cape Verde Islands is the first hard evidence of migration between the two. The IWDG also photographed distinctive humpback flukes (tails) off the Cork coast in 2001 and 2002, and next month will make another attempt to match them in the Cape Verde bays.

The monitoring of underwater hydrophones off our western seaboard has recorded the passage of singing humpbacks, all heading south, between mid-October and late March.