Petrels are ocean-going birds that include the gull-like fulmar and its smaller, sooty relatives, the storm petrel and the Leach’s petrel. They spend their lives gliding over the waves in search of food, only visiting land to breed.
The fulmar, together with the storm petrel and the Leach’s petrel, are all related to the giant albatross and the shearwaters, aptly named after their habit of skimming low over the waves.
The fulmar looks completely different compared to the other two petrels. It is about double the size of its relatives, mainly white, and similar to a gull.
It nests on open cliffs and, in summer, can be seen all day long near the coast. The storm petrel and the Leach’s petrel are small for seabirds and are sooty black all over, apart from a white patch on the rump.
They come ashore to their nests, deep burrows, or natural crevices in the rocks, but only after dark.
All petrels are distinguished from other seabirds by their complex beak structure. Viewed close up, the beak comprises a series of plates of horny material, with clearly visible joints or sutures in between.
The ridge of the beak is topped with a horny tube that gives the group another colloquial name, tubenoses.
The precise function of this narrow tube is not properly understood. One theory is that it gives petrels an air-speed indicator, similar to airplanes.
Another theory suggests that it functions as a genuine nostril. The sense of smell is poorly developed in most birds, but many petrels emit a powerful, musty odor, and returning birds may scent out their mates after dark and deep in nesting burrows.
The fulmar is at the center of one of the most amazing bird success stories of the last 100 years. For over 900 years, the only known British breeding station was on the remote island of St Kilda, 50 miles west of the Outer Hebrides.
Then, in the middle of the 19th century, the Icelandic fulmar population began to expand, and in 1878 other colonies began to be reported on Scottish islands, the first on Foula.
Since then, there has been no stopping their spread. First, the northern islands were colonized, followed by the cliffs of both the east and west coasts of Britain and Ireland, and by 1970 fulmars were nesting on all suitable stretches of the rocky coast.
Even in some quite unsuitable areas, they find a way to succeed. In the Hebrides, there are nests on the ground in remote and undisturbed dunes and on the cliffless coasts of southern and eastern England.
The birds have even commandeered nuclear power station window sills as the nearest alternative to a cliff ledge.
Fulmars have also moved inland. Nesting was first reported on ruined buildings in the Shetlands but now quarries several miles from the sea in northern England have breeding pairs.
It is unknown whether there was a genetic change in the birds or whether the North Atlantic warmed slightly and produced more fish. A more likely explanation is related to the fulmars’ diet, which consists mainly of offal.
The rise in numbers coincided with when whaling peaked in the Atlantic, with abundant supplies of offal both at sea and near the shore. Although whaling has stopped, modern fishing has taken over this food-providing role.
Are Petrels Aggressive?
Birds normally resort to aggression only to protect their breeding territory from competitors or defend their feeding areas from predators.
Competition between birds is almost always confined to birds of the same species, with other birds being tolerated or ignored. The response to predators varies.
Starlings will gather and swoop around, mobbing a hunting kestrel, while the meadow pipit may attack against a marauding cuckoo.
The fulmar has an excellent adaptation to help it. Once in its digestive system, the fulmar’s plankton food is converted into an oily, smelly fluid.
The fulmar can spit this with a range of several meters with great accuracy at predators venturing near its nest.
Sometimes they will even pursue an intruder before shooting its spit. This causes the predator to land immediately and preens itself vigorously to remove the foul-smelling oil clogging its plumage.
Most birds, however, rely on plumage and posture to convey their aggression. Blackbirds will patrol each side of the invisible boundary between their territories.
Robins use their red breasts to warn rivals off their territory, even attacking model robins placed in their territory by researchers.
The fulmars’ success is particularly surprising due to their low reproductive capacity. Once they have fledged from their simple cliff ledge nests, fulmars remain adolescent, roaming around the North Atlantic for at least five years.
After this time, they visit the cliffs in spring and summer, trying to find a nest site and find a mate. This can take two or three years before they breed for the first time at about eight years old.
Only one large chalky-white egg is laid, which often cannot be replaced if lost to a predator.
The dangers faced with a lengthy breeding cycle are offset by the lifespan of this bird. Fulmars may live for as long as 40 years. At that rate, even if laying only one egg a year, the fulmar pair have enough time to produce offspring several times over and ensure the population continues.
Fulmars are excellent birds to watch fly. They are expert gliders, rarely flapping their wings except on a still day. Gull-sized and grey and white in color, they may look dumpy with short, slender, and stiff wings held slightly down-curved, but they are very well streamlined.
Their large eyes are set deep in grooves in the feathers, and, except when the birds are on the nest, their feet are normally concealed, tucked up in the body feathers.
Near the cliffs, fulmars use their webbed feet to assist in steering or to make fine adjustments to their flying techniques. They seem able to take advantage of any wind, cutting diagonally across the wind and downwind in a shallow dive before turning sharply into the wind to gain height again. They then repeat the process.
Even the slight up-currents raised by the face of oncoming waves are exploited for aerodynamics.
Storm petrels are sooty black, apart from a white patch along the rump, which divides off the square, black tail. They nest in great numbers on islands and can be heard purring in their burrows.
The Leach’s petrel is slightly larger than the storm petrel, with a grey patch on the wing, a forked tail, and a dark line down the center of its rump. It nests only on a handful of remote islands like St Kilda, where its wild whooping and whistling song can sound quite chilling to the birdwatcher.
The breeding grounds are on islands off Greenland, Newfoundland, southern Labrador, Maine, and New Brunswick, Maine, with populations on the Faeroes and Westmann Islands. The majority winter in the tropical Atlantic is off the west coast of Africa and the north-eastern coast of Brazil, and the eastern tropical Pacific Ocean.
Towards dusk, petrels journey back home to land, either loaded with plankton for their offspring or anxious to relieve their mate, incubating the small, almost spherical white egg. Before they enter their nest, these birds gather offshore to await the dark and the safety that darkness brings from predators such as the great black-backed gull.
In winter, these small petrels become pelagic (birds of the open sea.) They cover the oceans in their search for minute food items from the surface plankton, which they gather while swimming or by dipping down to the waves in flight.
Often storm petrels follow in the wake of ships, using their feet on the surface, for mile after mile in the hope of collecting a meal from the scraps tossed overboard.
In the days of sailing ships, this habit earned them the name ‘Mother Carey’s chickens’ with sailors, named after Mater Cara, the sailors’ name for the Virgin Mary.