Films and novels often open with a seagull alone amid earth and sky. For many people seagulls are a symbol of loneliness and independence.

In fact, however, there are many different types of seagulls and they are by no means solitary in their habits.

The class of seagulls consists of six different families, of which the tern family and the gull family are the most common in Taiwan. These two families share a number of similarities in morphology and behavior.

Terns and gulls look so alike to most people that they would be hard put to tell them apart, but to the expert eye they are very different.

There are 49 species of gulls in the world. Gulls are plump-bodied with a short thick neck, a stout bill with a long hooked upper beak, a round or squared tail and large webs well adapted for swimming.

The tern family includes 42 different species found all round the world. Terns have a slender body which is smaller than a gull's, and a blunter bill without a hook. Due to their forked tails they are also known as "sea-swallows."

Both gulls and terns are seabirds, of which there are over 300 different species worldwide. These only account for 3% of all bird species, but they often appear in large numbers and colonies of a million birds have been recorded. Before it was disturbed by visitors Cat Islet in the Pescadores was home to vast colonies of sooty terns and little terns.

Most seagulls are fairly uniform in coloring. Their plumage is a combination of black, white, brown or gray with only a small minority displaying other colors.

However seagulls do exhibit great variety in the color and shape of their bills, some being as sharp as a dagger, some curved like a sharp hook, or with a large pouch. This is the most striking part of the seagull's body.

Some seabirds live for long periods at sea and only return to breed on land at the age of seven or eight. Seagulls often live in coastal waters or beside large inland lakes. By day they fly over the sea to catch fish, returning to shore at dusk. They usually fly no more than 20 km. from shore, so mariners rejoice when they see flocks of terns or gulls at sea because land cannot be far off. Some seagulls even live permanently in harbors or in parks near the coast where they scavenge scraps left behind by picnickers.

Eighteen species of the seagull family have been spotted in Taiwan, twelve being terns. The little tern is the most commonly sighted and appears in the largest numbers.

The little tern is widespread throughout the world. Colonies of them winter in Taiwan, with a small minority staying here all year round.

It is the smallest species in the seagull family with a body length of between 20 and 28 cm. and a wingspan of about 50 cm. It has a slender body with a black cap and a white bluish-gray plumage. The bill and legs are yellow, but in winter its black cap turns white and the bill and legs turn black.

Terns mostly nest by the seashore, by estuaries or in marshland. In Taiwan, for example, they are to be seen at the Tatu River estuary. Apart from in the breeding season the little tern spends most of its time hovering low above the sea looking from side to side with its beak pointing down as it searches for its prey. Once it has found its target it plunges vertically down to catch it.

In his book Waterbirds of Taiwan Chang Wan-fu, biology professor at Tunghai University, points out that the little tern can also dive for fish. After catching its prey it soars straight up into the air from the water.

Chang Wan-fu thinks the following old poem perfectly captures the little tern:

On a chill, deserted autumn river

Hungry gulls fret as nighttime falls.

White heads bobbing like old fishermen

They fish intently in the stream.

Boldly advancing to spot a fish

They quickly hide among the reeds again.

In a moment one brings its catch on shore,

The tail still jutting from its bill.

In this ornithologist's opinion the old poet had considerable powers of observation.

The little tern nests in a colony and usually builds its nest on the sandy shore. The male bird offers a small fish to its mate, and sometimes a pair of birds will swoop together in the sky as if to display their flying skill.

Two or three eggs are laid in each nest, and the male and female take turns incubating them and feeding the young. The fledglings stay with their parents for four or five weeks before going their own way.

Studies have shown that even when a storm has covered their eggs in sand and swept away all landmarks, terns can still quickly find their unhatched offspring again.

They will also defend their nest and have several ways of dealing with intruders. Besides simulating injury to draw the intruder away from the nest they will swoop ferociously and peck the intruder's head with their hard bill.

Many seabirds, including the tern, live in the wide open spaces of the ocean. To understand more about them you might have to be prepared to spend long periods at sea yourself.

[Picture Caption]

A family of little terns photographed at the Tatu River estuary by nature photographer Ch'en Yung-fu.

Right pictures show little terns in summer, left picture shows them in winter when their bills turn from yellow to black.

"In a moment one brings its catch to shore, the tail still jutting from its bill" is indeed an apt description of the tern.

Tired of flying, a tern rests on the shore and preens its plumage in comfort.

A family of little terns photographed at the Tatu River estuary by nature photographer Ch'en Yung-fu.

Right pictures show little terns in summer.

left picture shows them in winter when their bills turn from yellow to black.

"In a moment one brings its catch to shore, the tail still jutting from its bill" is indeed an apt description of the tern.

Tired of flying, a tern rests on the shore and preens its plumage in comfort.