Masked Boobies, Galapagos Islands, Ecuador

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Right: A mated pair of Masked Boobies. [Published full-page in Eagle-Eye Tours Travel Schedule 2006.] See more Masked Booby images below.

Galápagos Islands
Ecuador, South America

Contents of this page: Geology of the Galápagos Islands , Galápagos Sea Lion , Blue-footed Booby , Swallowtail Gull , Masked Booby , Prickly Pear Cactus Tree , Galápagos Giant Tortoise , Frigatebird , Bottle-nosed Dolphin , Heron , Pelican , Vermilion Flycatcher , Lava Lizard , Galápagos Land Iguana , Galápagos Sea Iguana

In 1959, Ecuador declared 97% of the land area of the Galápagos Islands to be Galápagos National Park, which UNESCO registered as a World Heritage Site in 1978. In 1986, Ecuador added a Marine Reserve to protect the surrounding waters, which were registered in 2001 as another World Heritage Site.

Geology of the Galápagos Islands:

Layers of volcanic debris plus some uplifting formed the Galápagos Islands, which are still one of the most active volcanic regions in the earth's oceans. Huge submarine volcanoes have joined into the Galápagos Platform, which rises 6,600 to 10,000 feet above the surrounding sea floor. About ten million years ago, the first island of the Galápagos archipelago burst above the ocean. The Galápagos Islands reach a maximum height of 5600 feet above sea level on Isabela, the largest island.

Right: Sea lion. Galápagos Islands, Ecuador.

Galápagos Sea Lion:

Galápagos sea lions are a subspecies of the Californian sea lion. Female sea lions can mate after five years of age, and can live to twenty. Males can mate a little earlier, but live shorter lives. Female sea lions bear a single pup each year, which they suckle for one to three years. You can often see two differently aged pups suckling from one mother. Pups begin fishing for themselves after five months, and gradually wean from mother's milk. Fearful of sharks, sea lions restrict their pups to shallow water. Often, one female will baby-sit a nursery of pups while the other mothers go fishing. The dominant, territorial bull will often guide youngsters to safe areas of the beach.

Female sea lions can choose a bull for mating, and can roam from the beach of one dominant bull to another. Females become sexually receptive about three weeks after giving birth, and males fight most severely over territory about this time. Most male sea lions lack a harem, and they frequently challenge the dominant bull with posturing, barking, pushing, or biting to try to gain territorial rights. When not challenging dominant bulls, the bachelor males usually gather in relatively peaceable bachelor colonies on less desirable areas of the coast, such as rocky cliffs.

Left: Blue-footed Booby male on left and female on right. A dark pigment surrounding the female's eye pupil makes it look larger than the male's.

Below right: Blue-Footed Booby male shading his egg on a typically spartan ground nest.
Blue-Footed Booby male bird with egg on nest. Galapagos Islands, Ecuador

Below right: Affectionate Swallowtail Gull pair.

Left: Blue-footed Booby female on nest with one chick.

Male Blue-Footed Booby on nest with two chicks.
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Blue-footed Booby:

The blue-footed boobies parade their bright blue feet prominently during courtship. Courtship includes an elaborate sky-pointing display in which each booby in the pair alternately lifts each foot, then raise its wings and beak skyward. Males give a long whistle and females give a nasal honk. During courtship, one of the pair will place a stone or twig ceremoniously onto a symbolic nest, or will touch its long bill with the bill of its partner. Before a female lays an egg, she scrapes away the stones or twigs of the symbolic nest and lays the egg on the bare ground. This ritualistic nest-building behavior bonds the pair, and is a remnant of evolutionary history when blue-footed booby ancestors constructed real nests. The related red-footed booby still constructs nests in trees. Female blue-footed boobies have a ring of dark pigment around their pupils, which makes their pupils appear larger than those of males.

Blue-footed boobies lay one to three eggs about three to five days apart. After the chicks hatch, the parents feed the largest chick first, which is usually the first born. If food is in short supply, the larger chick out-competes its sibling, causing the smaller chick to starve. Sometimes the larger chick forces its sibling out of the nest, and the parents won't allow the displaced chick to return. Although this behavior seems harsh, it helps guarantee enough food for the remaining chick to survive during hard times.

Both male and female blue-footed boobies share the responsibility to bring fish to their chicks. The naked hatchlings require a parent on the nest at all times for protection and temperature regulation. After the chicks grow a coat of white down and can pant to cool themselves, both parents may risk leaving the chicks to go fishing. Frigatebirds, hawks, and owls may take unguarded chicks. However, the chicks soon grow too large to be threatened by predatory birds.

Left: Male Blue-Footed Booby. Galápagos Islands, Ecuador.

Below right: Blue-footed Booby.
Blue-footed Booby. Galapagos Islands, Ecuador.

Masked Booby:

Below: Masked Boobies groom each other as a pair bonding ritual.

94GAL-09-29-Masked-Booby+egg.jpg
Masked Booby with egg in bare ground nest.

Masked Booby pair.

94GAL-09-22-Masked-Booby-chick+parent.jpg

Left: Masked Booby parent grooming its downy chick.

Below right: Andando sailboat. Galápagos Islands, Ecuador.
Andando sailboat. Galapagos Islands, Ecuador.

Prickly Pear Cactus Tree:

Two prickly pear cactus trees grow behind the tortoise in the photograph below. Prickly pear cacti grow into trees with trunks up to 4 feet (1.25 meters) in diameter on Santa Fe Island. On other islands, prickly pear trees can reach 40 feet (12 meters) in height. You usually find the taller species of prickly pear on islands where they compete with dense vegetation and contend with giant tortoises, which eat their pads. Shorter species of prickly pear are usually found on islands with sparse vegetation and no tortoises. Various observations suggest that competition for light and consumption by tortoises has influenced the evolution of the fourteen diverse types of Galápagos prickly pear. Prickly pear pads provide the major food source for tortoises and land iguanas. The fruits sustain Galápagos doves, mockingbirds, and land iguanas. Native Galápagos cactus finches depend upon the flowers, fruits, and seeds of the prickly pear cactus for survival.

Galapagos Tortoise. Galapagos Islands, Ecuador.

Galapagos Tortoise. Galapagos Islands, Ecuador.

Left: A 5-foot long Galápagos Tortoise walks by two prickly pear cactus trees. Santa Cruz Island, Galápagos Islands, Ecuador. [Published in Wilderness Travel 1990 Catalog.]

Galápagos Giant Tortoise:

The giant tortoise inspired the name of the Galápagos Islands. "Galápagos" comes from the Spanish word "galapago" meaning "saddle," which refers to the saddle-shaped shell found on some giant tortoise subspecies. Along with the Aldabra tortoise of the Seychelles in the Indian Ocean, Galápagos giant tortoises are the largest living tortoises. They can measure five feet (1.5 meters) over the curve of their shell, and can weigh up to 550 pounds (250 kilograms). The shell of the tortoise in this photograph measures about four feet.

Along with other members of the turtle order, Galápagos giant tortoises have a bony shell which is fused with their ribs and some other skeletal bones. The plates of the shell grow at the outer edges, but the rings gradually wear away and cannot reveal a tortoise's age. Galápagos giant tortoises may live up to 50, 150, or even 200 years, but no one knows for sure. The growth of large lichen and fungi patches on the shells of older tortoises hints at their great age. Because tortoises cannot mate until age 20 to 25, and because they live life in the slow lane, they can most likely outlive humans.

Despite the tortoise's extensive body armor, the exposed skin attracts parasites such as ticks. To eliminate parasites, tortoises (and iguanas) have adopted a mutually beneficial cleaning relationship with mocking birds and finches. When a tortoise wishes to be cleaned, it stands erect to expose all skin areas, as shown in this photograph. The mocking birds and finches have learned that tickling the tortoise's neck tells the tortoise to stretch out and expose tasty ticks and mites.

Since the Galápagos Islands formed several million years ago, enough time has passed for a number of hardy reptile species to drift by and gain a foothold. Rafts of vegetation released by flooding rivers have been known to carry animals for hundreds of miles. The giant tortoise originally came to the Galápagos Islands from continental South America, probably floating for two weeks in the prevailing westward ocean currents. Genetic studies indicate that the fourteen subspecies of Galápagos giant tortoises evolved from a common ancestor that probably first colonized San Cristóbal Island. From there the tortoises spread to the other Galápagos Islands, such as to the cloud forests atop the volcanoes of Isabela Island. Each of the five volcanoes of Isabela Island have been sufficiently isolated to support the evolution of their own distinct subspecies of Galápagos giant tortoises.

Four out of the original fourteen subspecies of Galápagos giant tortoises were decimated by whalers, sealers, and settlers, and are now extinct. To restore remaining tortoise populations, the Charles Darwin Research Station on Santa Cruz Island raises baby tortoises up to age five, when they reach a size safe from most predators. Scientists repatriate each tortoise subspecies to its native island or volcano. Each subspecies has a uniquely shaped shell. On dry islands, tortoises have saddle-shaped shells which allow them to reach high into the sparse vegetation. On wetter islands that have plentiful low vegetation, tortoises tend to have low, helmet-shaped shells. This distribution of giant tortoise subspecies greatly influenced Darwin's theory of evolution. Through natural genetic variation and natural selection, each tortoise subspecies evolved a unique shell shape that better survived local conditions.

Magnificent Frigatebird:

Above: Magnificent Frigatebirds nesting. Galapagos Islands, Ecuador, South America.

Magnificent Frigatebird with his bright red pouch displayed.

Magnificent Frigatebird male flying with his bright red pouch displayed.

Young Magnificent Frigatebirds in their nests.

Bottle-Nosed Dolphin:

Left: Bottle-nosed dolphins surf the compression bow wave of our ship.

Yellow Crowned Night Heron:

Brown Pelican:
A Brown Pelican dries its wings, Galapagos Islands, Ecuador, South America.

Vermilion Flycatcher (on Santa Cruz Island):

Lava Lizard:

The lava lizard, which grows much smaller than an iguana, is very common in the arid lowlands on most of the Galápagos Islands. Lava lizards can live up to ten years. Vision is the most important sense for a lava lizard, and it frequently climbs to the highest rock in order to keep watch on its territory. Both males and females have territories, but they only defend against members of their same sex. Males can mate after three years of age, and females can mate after only 9 months of age. Females sport a red throat during breeding season. Lava lizards see the colors red and yellow most clearly. (Images available upon request.)
Land Iguana. Galapagos Islands, Ecuador.

Land Iguana. Galapagos Islands, Ecuador.

Left: Galápagos Land Iguana.

Galápagos Land Iguana:

Galápagos land iguanas prefer drier areas, and obtain water primarily from their diet. They eat mainly prickly pear cactus fruits and pads, usually without removing the spines. Land iguanas reach sexual maturity after eight to twelve years, and can live more than sixty years. Males turn a brighter yellow in mating season, and compete ferociously for territories that overlap female territories.

Galápagos Sea Iguana:

Galapagos Sea Iguana basking in the sun after eating algea in the ocean. Galapagos Islands, Ecuador.

Right: Galápagos Sea Iguana. Galápagos Islands, Ecuador.

Galápagos sea iguanas, or marine iguanas, live throughout coastal areas of the Galápagos Islands, and are the world's only sea-going lizard. They have evolved from land iguanas from the South American mainland, 650 miles to the east. Sometime in the past several million years, flooding rivers may have flushed rafts of vegetation into the ocean carrying the sea iguana's ancestors. The prevailing westward ocean currents take about two weeks to reach the Galápagos Islands, a short enough trip for hardy reptiles such as iguanas to survive. Through genetic variation and natural selection over thousands of generations, iguanas adapted to a life of foraging algae from the sea.

The sea iguana feeds off red and green algae found underwater and in intertidal zones. As a consequence of its high salt intake, the sea iguana has evolved the most effective salt glands of any reptile. The iguanas sneeze the salt out of their nostrils, which often leaves their heads encrusted in salt. During breeding season, which varies island to island, males show brighter colors and aggressively defend their territories.

Below: A meter-long Sea Iguana in breeding colors.

SEA IGUANA GALLERY:

Sea Iguana on rock.	Colorful Sea Iguana.
Sea Iguanas sunning near blowhole.	Sea Iguana
Female sea iguana digging nest
Sea Iguanas and Sally Lightfoot Crab.	Colorful Sea Iguana spines.
Sea Iguana head closeup.	Sea Iguanas grazing on seaweed & algae.
Me and a wild and fearless Sea Iguana.	Sea Iguana
Old male Sea Iguana.	Mature male Sea Iguana
Male Sea Iguanas in breeding colors.	Sea Iguana female.
Sea Iguana slouched on rock.	Sea Iguana resting leg.