Boobies are a small group of seabirds native to tropical and subtropical oceans throughout the world. Their diet consists mainly of fish. They are specialized fish eaters feeding on small school fish like sardines, anchovies, mackerel, and flying fish. When their prey is in sight, they fold their long wings back around their streamlined bodies and plunge into the water from as high as 80 feet, so streamlined they barely make a splash. They travel in parties of about 12 to areas of water with large schools of small fish. When the lead bird sees a fish shoal in the water, it will signal the rest of the group and they will all dive together. Surprisingly, individuals do not eat with the hunting group, preferring to eat on their own, usually in the early morning or late afternoon.
There are three varieties on the Galapagos: the blue-footed, red-footed, and masked boobies. They are all members of the same family, and are not only different in appearance but also in behaviours. The blue-footed and red-footed boobies mate throughout the year, while the masked boobies have an annual mating cycle that differs from island to island. All catch fish in a similar manner, but in different areas: the blue-footed booby does its fishing close to shore, while the masked booby goes slightly farther out, and the red-footed booby fishes at the farthest distances from shore.
Although it is unknown where the name “Booby” emanates from, some conjecture it may come from the Spanish word for clown, “bobo”, meaning “stupid”. Its name was probably inspired by the bird’s clumsiness on land and apparently unwarranted bravery. The blue footed booby is extremely vulnerable to human visitors because it does not appear to fear them. Therefore these birds received such name for their clumsiness on land in which they were easy, captured, killed, and eaten by humans.
The blue-footed booby’s characteristic feet play a significant part in their famous courtship ceremony, the ‘booby dance’. The male walks around the female, raising his bright blue feet straight up in the air while bringing his ‘shoulders’ towards the ground and crossing the bottom tips of his wings high above the ground. Plus he’ll raise his bill up towards the sky to try to win his mate over. The female may also partake in these activities – lifting her feet, sky pointing, and of course, squawking at her mate. After mating, another ritual occurs – the nest-building which ironically is never used because they nest on the bare ground. When the female is ready to lay her eggs, they scrape the existing nest away so she can nest on exposed ground. Sun-baked islands form the booby’s breeding grounds. When ready the female Blue Footed Booby lays one to three eggs.
After mating, two or three eggs are laid in a shallow depression on flat or gently sloping ground. Both male and female take turns incubating the eggs. Unlike most birds, booby doesn’t develop brood patches (areas of bare skin on the breast) to warm the eggs during incubation. Instead, it uses its broad webbed feet, which have large numbers of prominent blood vessels, to transmit heat essential for incubation. The eggs are thick-shelled so they can withstand the full weight of an incubating bird.
After hatching, the male plays a major role in bringing fish home. He can bring back a constant supply of small fish for the chicks, which must be fed continuously. The reason is that the male has a longer tail than the female in relation to his body size, which makes him able to execute shallower dives and to feed closer to shore. Then the female takes a greater part as time proceeds. Sooner or later, the need to feed the young becomes greater than the need to protect them and both adults must fish to provide enough.
When times are good, the parents may successfully fledge all three chicks, but, in harder times, they may still lay as many eggs yet only obtain enough food to raise one. The problem is usually solved by the somewhat callous-sounding system of “opportunistic sibling murder.” The first-born chick is larger and stronger than its nest mate(s) as a result of hatching a few days earlier and also because the parents feed the larger chick. If food is scarce, the first born will get more food than its nest mate(s) and will outcompete them, causing them to starve. The above system optimizes the reproductive capacity of the blue-foot in an unpredictable environment. The system ensures that, if possible, at least one chick will survive a period of shortage rather than all three dying of starvation under a more ‘humane’ system.