Reasons Why Teuri Island Became a Sanctuary for Seabirds

Teuri Island is a small island with a circumference of about 12 km, and as of 2024, it has a population of approximately 250 people. Despite its size, Teuri Island is considered a “paradise for seabirds,” with an estimated breeding population of around one million birds. Such a sanctuary for seabirds is unique within Japan, as even the neighboring Yagishiri Island, which is about 3 km to the east and of similar size, lacks a significant seabird population.

The reason behind this phenomenon can be attributed to the maritime climate around Teuri Island, particularly during winter when it is influenced by the Siberian high-pressure system from the continent. As a result, the island is continuously exposed to northwestern winds. Over millions of years, these prevailing winds have shaped the landscape, forming cliffs predominantly on one side of the island.

from Google Map

The red lines indicate the original location of the island.

from Google Map

The arrows indicate the direction of the wind. Cliffs were formed on the northwest part of the island where the wind directly hits.

Cliffs, which are among the most challenging terrains for mammals, including humans, become easily accessible for birds capable of flying. Consequently, seabirds, which primarily reside at sea, are not well-adapted to terrestrial life, leading them to choose cliff habitats for breeding where their predators find it difficult to access.

The slaty-backed gull, which breeds on cliffs.

The pelagic cormorant and the black-tailed gull, which breed on cliffs.

The most abundant breeding location for rhinoceros auklets on Teuri Island is on land with soil situated atop the cliffs. Rhinoceros auklets choose to nest on land, despite the presence of many predators, as it becomes harder for predators to spot them during the evening twilight when they return to their nests all at once at sunset. If there were tall trees around the nesting area, they would be at a higher risk of colliding with them in the dark. Therefore, they prefer nesting in areas without tall trees.

Thanks to the island’s strong winds, which prevent the growth of tall trees, Teuri Island provides the ideal conditions for rhinoceros auklets. They have a habitat where approximately 400,000 breeding pairs thrive, making it the world’s No. 1 breeding site for these birds.

Rhinoceros auklets return to their nests by diving into treeless grasslands.

In this way, a miraculous convergence of ideal conditions for seabirds has resulted in the creation of Teuri Island, where numerous seabirds breed. During the seabird breeding season, boat tours are also available, allowing visitors to observe seabirds and geological formations from beneath the cliffs.

Photo & text : Wataru HIMENO

★ Visit our web site of  TEURI ISLAND.

Contact us to make arrangements for photographing seabirds on Teuri Island and Wildlife of Japan.

★Wildlife videos are also available on Youtube – we have the playlist as well.

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Seabirds breeding on Teuri Island (Hokkaido)

Common murre, Common guillemot Uria aalge 

Common Murre or Common Guillemot has a distinctive penguin-like appearance due to its legs positioned at the back of its body. In Japan, they breed only in one place, a cliff cave near the red rocks on Teuri Island. The breeding site of the cave can only be observed from the boat, but they can sometimes be seen floating above the sea from the Akaiwa Observatory. In 2002 their numbers were reduced to 13, but now(2023) exceed 100 and is steadily increasing.

Common Guillemot
Common Guillemot

Spectacled guillemot  Cepphus carbo 

Spectacled Guillemots, with their very cute red legs and red mouth, breed in the crevices of the cliffs that stretch from south-west to north of Teuri Island. The moment when the Spectacled Guillemot takes off after running on the surface of the water is one of the most beautiful moments, when the colour of the sea, known as ‘Teuri Blue‘ and the bright red legs of the Spectacled Guillemot shine brightly. Take chance to watch it up close from a small seabird-watching boat that run s early in the morning (reservation is a must).

Spectacled Guillemot running on the surface of the sea, with beautiful red legs
Spectacled Guillemot, observed from Akaiwa Observatory

 Rhinoceros auklet  Cerorhinca monocerata 

As its name suggests, Rhinoceros Auklet has a rhinoceros horn-like projection that appears during the breeding season from April to July. It is said that there are currently 800,000-1,000,000 rhinoceros breeding on Teuri Island, and the sight of them all returning to their nests at dusk is the one to behold. Because they dig holes in the ground to build their nests, which is quite unusual for bird species, photographers can observe them relatively closely when they return home.

Rhinoceros Auklet returning nest in the setting sun
Rhinoceros Auklet carrying fish to its chicks waiting in the nest

Ancient murrelet  Synthliboramphus antiquus 

On Teuri Island, they are seen every year from late May to early June. Several birds form groups up to 10 birds and feed on zooplankton and other organisms. Because they are very small and frequently dive, it is very difficult to observe them on days with high wave swell. It is said that they breed only on Teuri Island in Japan – take the rare chance to capture them here.

Ancient murrelet
Ancient murrelet

Pelagic Cormorant  Phalacrocorax pelagicus

This cormorant normally lives in the open sea. During the breeding season when they come to Teuri Island, their entire bodies are covered with a amazingly beautiful sheen, and the base of its beak is stained red. They can build their nests in small bumps and hollows in cliffs, using saliva and mud to harden very fine nesting material, so natural enemies such as mammals cannot approach their nests.

Pelagic Cormorant at nesting site, with chicks
Pelagic Cormorant carrying nesting material

Japanese cormorant  Phalacrocorax capillatus 

A species of cormorant widespread across Japan. During the breeding season, its head turns white. Cormorants hunt deep underwater where visibility is poor, so they have blue eyes that are easy to see when viewing in the dark. They have a low oil content on their body surface to facilitate swimming easily underwater, and can be observed spreading their wings on rocks to dry their bodies after swimming.

Japanese cormorant
Japanese cormorant

Black-tailed gull  Larus crassirostris

This species of gull is characterised by its yellow legs and tail with a black band. On Teuri Island, their numbers have increased dramatically in recent years, with the estimated number of nests doubling from two years ago in 2021 to around 5,000 now in 2023. Kurosaki Beach (literally “Black-cape beach” in Japanese), a major breeding ground for Black-tailed gulls, is often called ‘Shirasaki Beach (“White-cape beach”)’ because its black rocks have turned completely white from their excrements.

Black-tailed gull
Black-tailed gull

Slaty-backed gull    Larus schistisagus 

A large gull with pink legs and a bright white tail. It reigns at the top of the biological pyramid on Teuri Island, and will swallow an adult Rhinoceros Auklet up to 38 cm long awhole. Black-tailed gull chicks, pit vipers and sea urchins are other favorites. If you see sea urchin shells lying around town, they are often the remains of the Slaty-backed gull’s meal.

Slaty-backed gull eating sea urchin

This Slaty-backed gull, just after swallowing a whole Rhinoceros Auklet, has its wings overflowing from its mouth and its chest is swollen with Rhinoceros Auklet!

 

Photographs & report: Wataru HIMENO

Observation period: May-July 2023, Teuri Island, Hokkaido, Japan

★ Visit our web site of  TEURI ISLAND.

Contact us to make arrangements for photographing seabirds on Teuri Island and Wildlife of Japan.

★Wildlife videos are also available on Youtube – we have the playlist as well.

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