TUBENOSED SEABIRD – Procellariiformes

TUBENOSED SEABIRD

TUBENOSED SEABIRD FACTS

Tubular nostrils are common to every procellariiform (member of the order Procellariiformes). In the albatross, the nostrils stick out from both sides of the bill. In the other three families, the nostrils sit at the base of the upper bill. Procellariiforms differ from other birds in that they have a highly developed sense of smell, which helps them locate food and breeding sites. Procellariiforms’ bills are split into seven to nine horny plates, and the upper bill is hooked. This sharp hook, which is actually formed by a plate, allows the birds to hold onto slippery foods such as fish and squid.

No other bird order has as large a size range as these seabirds. The storm-petrel weighs less than 1 ounce (20 grams) and has a wingspan of 12.5 inches (32 centimeters). The largest species, the albatross, can weigh more than 24 pounds (11 kilograms) and has wingspan of up to 12 feet (3.6 meters).

Procellariiformes are covered in black, gray, brown, and white feathers. Most have black legs and feet, though the shearwaters’ are blue. The bills are dark gray or black and often have a distinct yellow, orange, or pink coloration.

Procellariiformes have oil in their stomachs that acts as a food source during the long periods between meals. In addition, the oil is used as a defense mechanism. When threatened, chicks and ground-nesting adults regurgitate (re-GER-jih-tate), bring up from the stomach, the oil and spray it over their predators. The oil cools to a waxy substance that damages the feathers of the enemy birds.

GEOGRAPHIC RANGE

No other birds have as wide a distribution as the Procellariiformes. They are found in Antarctica as well as Greenland and in every ocean across the globe.

TUBENOSED SEABIRD HABITAT

Tubenosed seabirds are found mostly on islands with few land-based predators. Those that nest on the mainland do so primarily in deserts or mountainsides, where there are fewer predators. Because the larger birds need strong winds to help them get airborne, breeding sites must be windswept. This makes the sub-Antarctic islands perfect for breeding. Unless they are breeding, these birds spend their time on the ocean where food is abundant. Some species migrate, move from place to place, between the Northern and Southern Hemispheres, repeating the same migration pattern each year.

TUBENOSED SEABIRD DIET

Larger seabirds such as the albatross eat mostly squid, though they snack on other seabirds and carrion, dead, rotting flesh, as well. They eat the carcasses of seals and whales while the smaller seabirds eat the leftover scraps. Only the larger seabirds look for food on land. All Procellariiformes take advantage of the behavior of whales, dolphins, sharks, and tuna. When these predators push schools of fish close to the surface in order to eat them, tubenosed seabirds dive down and snatch them from the water. These seabirds usually get their food from just below or on the surface of the water, though some of the species can dive more than 30 feet (10 meters) below the surface if necessary.

BEHAVIOR AND REPRODUCTION

Procellariiforms live in groups, even when breeding. Although their flocks often contain numerous species, fights occur frequently, with the larger species forcing out those smaller birds. Unless competing for food, most procellariiforms are silent on the water. However, when nesting on land, they communicate with shrieks and calls.

These seabirds breed slowly, laying just one egg each season. The mother sits on the egg anywhere from six to eleven weeks. Once born, chicks take two to nine months before they can fly independently. This waiting period is longer than that of most birds. Experts believe this is because there are very few predators, animals that hunt them for food, on the islands where these birds build their nests, so there is no pressure for the chicks to learn to fly quickly. Procellariiforms do not breed during the first year of life, and larger species wait over ten years before they first breed.

During breeding season, tubenosed seabirds build their nests on the ground in large colonies. Both sexes help build the nest, and both help raise the chicks. Though procellariiforms do choose just one mate, evidence has shown that males are involved in pairings outside the primary relationship.

TUBENOSED SEABIRDS AND PEOPLE

Because of their ocean habitat, procellariiforms have a long history of interaction with fishermen and seafarers. These birds help fishermen locate fish and other marine life. In addition, their archaeological remains have been found around the world. Today, only the shearwater species is eaten, as are the eggs of the petrel. Humans also use the feathers of the albatross in the hat-making industry, and petrel is often used as bait by fishermen. Some communities use the stomach oil of procellariiforms as lamp oil and as an ingredient in medicine.

CONSERVATION STATUS

Twenty-three of the 108 species are threatened with extinction. One species, the Guadalupe storm-petrel, has become extinct since 1600. The primary threat is the introduction of predators to the breeding islands.

Prior to 1991, drift-net fishing was allowed. This is a type of fishing in which large nets were cast onto the waters and then hauled in. Although drift-nets efficiently caught large numbers of fish with little effort, they also caught other wildlife, including dolphins and seabirds. Drift-net fisheries were believed to be responsible for the deaths of 500,000 seabirds every year. Despite the ban on drift-net fishing, thousands of procellariiforms are still killed by long-line fisheries, a method in which long, thick hooks are baited and cast out to sea; the hooks often get caught in the necks of albatrosses, and this method catches a lot of “trash” sea life, similar to drift-netting fisheries, and trawl, a bag-like net is carried along by a boat, catching everything in its wake. A 1991 study estimated that 44,000 albatrosses are killed in Japan each year by these methods.