What kind of bird is a stork? The latest information on its characteristics, ecology, and habitat.

What kind of bird is a stork? We will explain its characteristics, ecology, and habitat. The stork is a carnivorous bird that lives near water, and I think Japanese people are very familiar with it. They are migratory birds and migrate to different areas.

What is a stork? About basic status

The stork is a bird classified in the genus Stork, in the order Avena and the family Storkidae. The scientific name is Ciconia boyciana. The total length is 110 – 115 cm, the weight is 3 – 5 kg, the wingspan is 58 – 67 cm, and the wingspan is 195 cm. Research is ongoing and photos and videos can be viewed online.

Japanese（和名）	コウノトリ
English（英名）	Oriental white stork/Japanese white stork
scientific name(学名)	Ciconia boyciana
classification（分類）	Ave、 Ciconiiformes、Ciconiidae、Ciconia 鳥綱、コウノトリ目、コウノトリ科、コウノトリ属
IUCN Status(保全状況)	VULNERABLE
Length（体長）	110 – 115cm
Weight（体重）	3-5kg

What are the roots and origins of the Oriental Stork?

The roots of the stork (specifically the Oriental Stork, Ciconia boyciana, which is currently the subject of conservation and reintroduction efforts in Japan) lie in large wetland birds that first appeared tens of millions of years ago.
Modern storks have evolved a lifestyle of using their long legs and large beaks to forage for prey in wetlands.

Origins of the Stork Family (Ciconiidae)

The stork family (Ciconiidae) represents a relatively ancient lineage among birds.

Origin: Approximately 30 to 40 million years ago (Cenozoic Era)

Center of distribution: The Old World (Africa, Europe, and Asia)

Early storks lived in environments such as:

Rivers

Lakes and ponds

Swamps

Watersides in grasslands

…and preyed on small animals.

What were their ancestors like?

The ancestors of the stork did not possess the large stature seen today; instead, they are believed to have been:

Relatively small waterside birds

Long-legged

Birds that walked through shallow water to forage for prey

Over the course of evolution, they adapted in the following ways:

Legs became longer

↓
Enabled foraging in deeper water

Necks became longer

↓
Enabled quick capture of prey

Beaks became larger

↓
Enabled predation on fish, frogs, insects, and small animals

Roots of the Oriental Stork

The Oriental Stork found in Japan is a species adapted to East Asia.

Distribution range:

Japan

Northeastern China

Korean Peninsula

Russian Far East

In Japan specifically, they have long lived by utilizing:

Rice paddies

Rivers

Wetlands

Japanese populations were once widely distributed, ranging from southern Hokkaido to Kyushu.

Why are they called “birds that bring happiness”?

Storks hold symbolic significance in various parts of the world. In Europe, the legend of the “baby-carrying bird” arose from observations of these migratory birds:

returning in the spring,

nesting near human homes,

and raising their young.

In Japan, too,

they have long been regarded as

birds of good fortune

and symbols of prosperous descendants.

About classification

Stork is a general term for birds belonging to the subfamily Storkinae. In Europe and northern Africa, there is a stork that is closely related to the white stork, and there is a strong opinion that they are the same species. However, both are now considered separate species.

分類体系（標準的な体系に基づく）：

• 界（Kingdom）：動物界（Animalia）
• 門（Phylum）：脊索動物門（Chordata）
• 綱（Class）：鳥綱（Aves）
• 目（Order）：コウノトリ目（Ciconiiformes）
  • かつてはペリカン目（Pelecaniformes）に含められることもあった
• 科（Family）：コウノトリ科（Ciconiidae）
• 属（Genus）：Ciconia
• 種（Species）：代表的な種として
  • Ciconia ciconia（コウノトリ、White Stork）
  • Ciconia boyciana（オオコウノトリ、Oriental Stork）
  • Ciconia nigra（クロコウノトリ、Black Stork）

Where is its habitat?

White storks are migratory birds that breed in the Amur and Ussuri river basins of northeastern China and southeastern Russia, and during the winter they migrate south to the Republic of Korea, Japan, Taiwan, and Hong Kong to overwinter.

1. White Stork (Ciconia ciconia)

Distribution: Europe, Africa, and western Asia

Migration: Winters in Africa and India

Habitat:

Waterside areas such as wetlands, rivers, lakes, and rice fields

Also found in open grasslands and around farmland

2. Great White Stork (Ciconia boyciana)

Distribution: Japan, China, the Korean Peninsula, and the Russian Far East

Habitat in Japan: Reintroduction and conservation efforts are underway in Hyogo Prefecture, Shiga Prefecture, and other areas

Habitat:

Around rivers, lakes, and wetlands

Wintering in wetlands in eastern China and the Korean Peninsula

3. Black Stork (Ciconia nigra)

Distribution: Eastern Europe, Central Asia, Siberia, East Asia (also migrates to parts of Japan)

Habitat:

Nests in rivers and wetlands within forests.

Prefers forest-like environments more closely related to the Oriental White Stork.

Migration: Winters in Southeast Asia and India.

4. Common Habitat Characteristics

Highly Water-Dependent: Prefers areas with an abundance of fish, frogs, and insects for prey.

Foraging in Open Lands: Forages in rice fields and grasslands.

Highly Migratory: Travels long distances depending on the season.

feature is? What kind of creature is it?

Storks look similar to cranes and are often mistaken for herons. White storks live in rivers, wetlands, and grasslands, and they are quite ferocious, as they often fight fiercely between members of the same species, leading to cases where they end up killing each other. A behavior called “cluttering” has been observed, where they violently peck at each other, as if slamming their beaks together. One characteristic of this bird is that it stops singing when it becomes an adult. Storks do not form colonies.

1. Physical Characteristics

Body Size: Large

Body Length: Approximately 100-115 cm

Wingspan: Approximately 155-215 cm

Weight: Approximately 2-4.5 kg (varies by species)

Body Color: Varies by species

White Stork (Ciconia ciconia): White body with black wings

Big Stork (Ciconia boyciana): White body with black wings and a red beak

Black Stork (Ciconia nigra): All black or a mix of black and white

Beak: Long and straight, adapted for foraging and grasping

Legs: Long and red to pink

Neck: Long, stretched during flight

2. Behavioral and Ecological Characteristics

Feeding Method

Preys on fish, frogs, insects, and small mammals near water

Uses its beak to search for prey in water and on land

Flight Ability

Capable of long-distance migration

Large wings enable energy-efficient movement by gliding and using thermal currents

Social

Travels in pairs during the breeding season

May migrate in flocks during the non-breeding season

3. Breeding and Nesting

Nests: In large trees, cliffs, roofs, etc.

Breeding: Oviparous, usually laying 2-5 eggs

Brooding: Both parents incubate and feed the eggs

Lifespan: May live for over 20 years in the wild

4. Overall Impression

Large, graceful waterbird

Long-distance migratory bird

White storks are known as “birds of good luck” and feature in legends and folktales

From a human perspective, they appear dignified, graceful, and approachable

What is the ecology like?

Storks mainly feed on small animals such as frogs, small fish, and insects. It needs to be in a place with a lot of living things and will eat 400-500g a day. Reproduction is oviparous. They court by arching their heads and clapping their beaks together (cluttering). They are monogamous and build nests in large trees. They lay 2 to 6 eggs and the brooding period is 55 to 70 days. The lifespan is about 35 years.

1. Habitat

Main Locations: Open water areas such as wetlands, rivers, lakes, rice fields, and grasslands

Distribution: Varies by species, including Europe, Asia, Africa, and Southeast Asia

Characteristics: Prefers environments with abundant food and easy nesting

2. Behavior

Diurnal

Forages and flies during the day

Many are migratory birds

Migrates long distances depending on the season (white storks range from Europe to Africa)

Flight Ability

Glides with their wings spread, using thermal air currents for energy-efficient flight

3. Diet

Omnivorous, but primarily feeds on aquatic organisms

Fish, frogs, insects, small mammals, etc.

Searches for prey in water and on the ground with their beaks

Foraging Behavior

Searches for food while walking in shallow water or rice fields

Quickly captures prey once found

4. Breeding and Nesting

Nests: On large trees or on building roofs

Breeding Season: Spring to early summer (varies by region)

Number of Eggs: 2-5

Brooding: Both parents incubate and feed

Development: Chicks leave the nest at about 2 months and begin foraging on their own

5. Sociality

Breeding Season: Pairs build nests and raise their young

Non-breeding Season: Sometimes migrate in flocks

Communication: Communicate through beak tapping, wing buzzing, and calls

6. Ecology Summary

Diurnal, migratory, large, water-dependent birds

Diet: Omnivorous, primarily feeding on fish and frogs

Both parents cooperate in nest building and brooding

High flying ability, capable of long-distance migration

Oriental Stork Vocalizations

Storks (specifically the Oriental Stork, Ciconia boyciana) rarely “sing” like typical birds.
Their most distinctive characteristic is communicating through sound by clattering their beaks together—a behavior known as “bill-clattering.”

Characteristic Sound: Kata-kata-kata…

The primary sounds made by the stork are

“Kata-kata-kata-kata…” or

“Ka, ka, ka…“

—dry, rapid, repetitive sounds.

These sounds are not produced by the vocal cords;

instead, they are created by rapidly striking

the upper beak

against the lower beak.

Why don’t they vocalize?

As adults, storks lack a well-developed vocal organ (syrinx) in the throat, limiting their ability to produce complex vocalizations.

Instead, they convey their intentions using

their beaks,

posture, and

wing movements.

This is a trait common to large stork species.

Situations where bill-clattering is used

① Courtship and pair bonding

During the breeding season, pairs face each other and engage in behaviors such as:

arching their necks far back,

clattering their beaks, and

bobbing their heads up and down.

These actions serve to confirm their bond as a pair.

② Communication at the nest

At the nest, the sound is used for:

signaling between mates,

greeting a partner returning to the nest, and

stimulating the chicks.

Parent birds and chicks recognize each other through these sounds and movements.

③ Alerting and intimidation

When other birds or animals approach, they issue a warning by:

clattering their beaks vigorously,

extending their necks, and

making their bodies appear larger.

Seasonal Activities

The annual activity cycle of the Oriental Stork (Ciconia boyciana) consists of breeding, rearing young, migration, and overwintering.
In Japan, they inhabit areas such as Toyooka City, Hyogo Prefecture—where reintroduced populations are concentrated—utilizing wetlands, rice paddies, and rivers.

🌸 Spring (March–May): Breeding and Rearing Begin

Key Activities

Pair formation

Nest building

Egg-laying

Incubation

Spring is the most critical season for the Oriental Stork.

Behaviors:

Repairing the nest as a pair

“Clattering” (clicking their beaks together)

Courtship displays on the nest

Breeding

Number of eggs: Typically 2–6

Incubation period: Approx. 30–35 days

Male and female take turns incubating the eggs

☀️ Summer (June–August): Chick Growth and Fledging

Key Activities

Feeding chicks

Flight training

Hunting practice

Parent birds return to the nest multiple times a day to feed the chicks:

Fish

Frogs

Snakes

Insects

Small mammals

Chick Growth

Able to fly at about 2 months of age

Continue to receive food from parents for a while after fledging

Often remain in family groups until autumn

🍂 Autumn (September–November): Migration and Independence

Key Activities

Dispersal of young birds

Shifting foraging grounds

Searching for overwintering sites

Young storks move around,

Rivers

Rice paddies

Wetlands

Ponds

…searching for areas rich in food.

Adult birds also expand their range depending on the season.

❄️ Winter (December–February): Overwintering and Foraging

Key Activities

Foraging in wetlands and rice paddies

Resting in flocks

Preparing for the next breeding season

They do not enter a state of true hibernation in winter;

Fish

Frogs

Aquatic insects

Small animals

…they remain active while searching for these.

During cold periods, they engage in behaviors such as:

Resting on one leg

Fluffing up their feathers

Maintaining body heat in sunny spots

Flight Speed

The flight speed of storks (particularly the Oriental Stork, Ciconia boyciana) is typically around 40–60 km/h during normal flight, though it may be slower when gliding.

Normal Flight Speed

Approximately 40–60 km/h

During cruising flight, they move by slowly flapping their large wings.

As large birds, storks excel at gliding using thermal updrafts rather than relying on frequent flapping.

Migration and Long-Distance Travel

When migrating, storks gain altitude by utilizing:

Mountain slopes

Updrafts rising from ground heated by the sun

This flight method allows them to:

Reduce the frequency of wing beats

Conserve energy

Travel long distances

Flight Characteristics

Large wings

Wingspan of the Oriental Stork:

Approximately 2 meters

Their large wings enable them to:

Fly slowly

Glide for extended periods

Travel with minimal effort

Movement Between Nest and Foraging Grounds

In their daily routine, they:

Travel distances ranging from a few kilometers to several tens of kilometers from the nest

Fly to rivers or rice paddies

Return to the nest in the evening

Since there is no need to rush during these trips, their flight speed is relatively slow.

About Stork Chicks

This article provides a detailed summary of stork chicks (young birds), covering their appearance, growth, and behavior.

1. Birth and Early Characteristics

Egg Number: Usually 2-5

Hatching: Hatch in approximately 32-34 days (varies slightly depending on species and climate)

Weight and Size: Approximately 70-90 g immediately after hatching, approximately 15 cm in length

Feathers: Soft, downy feathers; adult black and white or red feathers have not yet developed

Eyes, Beak, and Legs: Small, pale in color

2. Growth and Development

Early Life: Carried and fed by parents in the nest

Feeding: Parents feed them digested fish, frogs, etc. by mouth

Feather Development: At 2-3 weeks of age, their body fur begins to change to adult feathers

Flight Preparation: At 6-8 weeks of age, their feathers are fully developed and they are ready to leave the nest

3. Behavior/Personality

Long waiting time in the nest: At first, they are mostly immobile and dependent on their parents.

Highly dependent on their parents: They have difficulty surviving without feeding and protection.

As they grow, they begin to move within the nest: They practice flapping their wings and bracing themselves.

4. Fleeting and Independence

Fleeting: They begin flying at 6-8 weeks of age.

Foraging: After leaving the nest, they learn how to forage while accompanying their parents.

Independence: After several months, they become able to forage independently.

5. Ecological Points

Early Life: Highly dependent on parents.

Relatively fast growth rate, allowing them to leave the nest at about 2 months.

Flight and foraging skills are learned within the nest.

Is the stork an endangered species?

Unfortunately, the white stork is listed as an endangered species. It has also been designated as a special natural monument of the country. The causes are as follows. The estimated population is around 2,000 to 3,000 birds. In Japan, plans to release birds into the wild and reintroduce them are being implemented. Parenting activities have begun in order to allow the birds to fly outdoors. We are developing a business to help chicks leave the nesting area.

It is difficult to secure food

Due to overfishing and the effects of pesticides, the number of loaches that they feed on has drastically decreased. This made it impossible to get enough food. It has disappeared in the wild in Japan.

A stork gets entangled in an artificial object

Land exploitation by humans is also a major problem. In addition to agricultural damage, the number of storks becoming entangled in man-made objects such as electric wires and electrocution cases is also increasing. Therefore, a breeding program has been started. They lay eggs and grow in rice paddies, etc., and then depending on the situation, they are allowed to leave the nest.

Can storks be kept?

Storks are migratory birds and have no concept of permanent residence. In addition, it is extremely difficult for the general public to keep as it is designated as an endangered species.

1. Difficulty of Raising

Large bird with excellent flying ability

Body length: 100-115 cm, wingspan: 155-215 cm

Requires ample flying space, which is difficult to secure in a home environment

Unique diet

Mainly feeds on fish, frogs, and insects

Requires live food and an aquatic environment, making it difficult to provide food at home

Migratory habits

Many species migrate long distances seasonally, which can be stressful in captivity

Due to their strong migratory instincts, confined environments can lead to health and reproductive problems

Sociality and breeding habits

Requires paired nesting and chick-raising during the breeding season

Breeding is difficult in solitary or unsuitable environments

2. Laws and Regulations

Oriental white storks are sometimes designated as endangered species, and international trade and breeding require permission.

In Japan, they are regulated by the Convention on International Trade in Endangered Species (CITES), and illegal breeding and import are prohibited.

3. Cases where they can be kept

Zoos and wildlife conservation facilities

For breeding programs, conservation, or exhibition purposes

Environments with access to food, water, and flight space

Home keeping is not practical

Stress, malnutrition, and lack of flight can cause health problems