Seabirds are really cool animals. They have an uncanny ability to not come to land for an exceptionally long time, which I find very neat, though I’m not sure why. Maybe it’s because to us the oceans have always been wild and untameable, and the fact that these birds spend most of their lives out at sea is impressive to us land loving humans. In any case, it’s time I talked about some cool seabirds, the storm petrels.
Storm petrels are the smallest seabirds, and compose the family Hydrobatidae. There are over 20 species of storm petrel, they are widespread. They are found in every ocean in the world and most seas, and only come to land to breed.
When you live on the ocean for most of your life, you have to have some adaptations to survive. Storm petrels certainly are good at living at sea. Almost all storm petrels are a dark grey or white, which presumably helps the birds camouflage on the stormy seas. They are notoriously difficult to identify, and apparently most pictures of storm petrels are labelled as the wrong type of storm petrel. Petrels also have a number of different flight techniques, using slope soaring to slip across the ocean’s surface. Basically this is possible because the wind hits the wave fronts, creating an upward draft that the birds can use to stay aloft. Because these birds are rarely on land, their legs are not very strong. In fact, a storm petrel’s legs can only support it for a few steps while on land. I think it would be pretty funny to watch a petrel on land. Step, step, fall. Step, step, step, fall. Repeat.
When feeding, petrels don’t usually land on the water. Instead, they hover or ‘walk’ above the surface and gobble up anything that comes to the surface. They can hover by flapping their wings extremely fast and facing into the wind to keep them in place. One species of storm petrel, the white-faced storm petrel, moves across the water by keeping its wings still and bounds across the water with its legs.
The only time of year when storm petrels come to land is in the breeding season. Most species breed on isolated islands, though some do breed in mainland colonies. Almost every species of storm petrel is active at the nesting site during the night, to avoid predators. Storm petrels are very attached to the places they were born, and return to the islands where they hatched. Some birds take this a little far, such as the band-rumped storm petrel that was found nesting 2m from the burrow in which he was born. Petrel colonies are huge, with colonies of Leach’s storm petrel having around 3.6 million birds. That would be one noisy island.
Storm petrels are highly monogamous, and form stable pair bonds that last for many years. These birds are also very faithful to their mates, as proven by DNA testing. One egg is laid per season, and both parents take turns incubating the egg, until it hatches in 50 days. They parents then look after the chick for a week before leaving it alone for the day. They return at night to regurgitate food and stomach oil into the chick’s mouth. This stomach oil is some amazing stuff: it has 9.6 calories per gram. This is slightly less energy than what is contained in diesel fuel. So I guess mom and dad are the gas pumps and the little chick is the truck they pump fuel into every day.
Seabirds in general are pretty amazing, but I think storm petrels are extra awesome. I like to picture them flying on a vicious stormy sea, because of their name. I bet they hate storms though. I know I would.
Note: Cover photo by Ben Lascelles.