Common Tern Diet and Size Feeding Habits, Predators, and Measurements

Common Tern Diet and Size: Feeding Habits, Predators, and Measurements

Ever watched a graceful seabird swooping over the waves and wondered what it was? Chances are, you might have spotted a Common Tern! 

These elegant flyers, with their sleek bodies and forked tails, are a familiar sight along UK coastlines and inland waterways. 

Common terns are medium-sized seabirds known for their striking black caps and long, pointed wings. These agile flyers are often seen diving into the water to catch their prey.

The Dietary Habits Of The Common Tern

Common Terns have a varied diet primarily consisting of fish and invertebrates. Their feeding techniques are fascinating and efficient, showcasing their adaptability in different environments.

What Does A Common Tern Eat?

Common Terns predominantly eat small fish, which make up the majority of their diet. They often target species such as sand eels, herring, and sprats. These birds catch their prey by diving from the air into the water, a technique known as plunge diving

Nestling Common Tern

In addition to fish, Common Terns also consume crustaceans and insects, particularly during the breeding season when they need to feed their chicks a high-protein diet.

When watching a Common Tern in action, you’ll see it hover gracefully above the water, pinpointing its prey before executing a swift, precise dive. With remarkable speed and accuracy, it captures its meal, often emerging with a small fish wriggling in its beak. 

This spectacle is a testament to the bird’s agility and keen hunting skills.

What To Feed A Baby Common Tern

Feeding a baby Common Tern involves providing small, easily digestible fish. Parents regurgitate partially digested fish to feed their chicks. This diet includes small fish like sand eels and herring, which are rich in nutrients necessary for the chicks’ growth and development. 

In some cases, parents may also feed their young small invertebrates to ensure a balanced diet.

It’s fascinating to observe how attentive Common Tern parents are. They take turns foraging and returning to the nest with food, ensuring their chicks are well-fed and healthy. 

The chicks, with their downy feathers and bright eyes, eagerly await each feeding, their tiny beaks opening wide in anticipation. This nurturing behaviour is crucial for the chicks’ survival and prepares them for the challenges of adulthood.

Breeding Habits Of Common Terns

The breeding behaviour of Common Terns is characterised by their social nature and elaborate courtship rituals. These birds typically nest in colonies, often on coastal islands or along shorelines.

Do Common Terns Mate For Life?

Common Terns often form monogamous pairs that may last for several breeding seasons. During courtship, males perform aerial displays and offer fish to females as a form of bonding. Once paired, they work together to build a nest, usually a simple scrape in the ground lined with vegetation. 

Both parents share incubation duties and care for the chicks, ensuring their survival​.

Watching a pair of Common Terns engage in their courtship rituals is a delightful experience. The male presents his mate with a fish, almost like a romantic gift, and performs aerial acrobatics to impress her.

The Size & Weight Of Common Terns 

Understanding the physical dimensions of Common Terns helps in identifying and studying these birds in their natural habitat.

How Much Does A Common Tern Weigh?

A fully grown Common Tern typically weighs between 90 to 150 grams. This lightweight build is essential for their agile flight and long-distance migration. 

Common Tern

Despite their small size, Common Terns are incredibly resilient. Their lightweight bodies enable them to undertake arduous migrations, travelling thousands of miles between breeding and wintering grounds. 

This incredible endurance is a testament to their adaptability and survival instincts.

How Big Is A Common Tern?

Common terns have a body length of about 31-35 cm, with a wingspan ranging from 77-98 cm. Their slender build and long, narrow wings allow for efficient flight and precise manoeuvring during hunting and migration.

This combination of compact body and large wings gives them an excellent power-to-weight ratio, enabling their impressive aerial abilities.

Are Common Terns Under Threat?

While common terns are not currently considered globally threatened, they face several challenges that impact their populations.

What Eats A Common Tern?

Predators of common terns include larger birds such as gulls and raptors, which prey on their eggs and chicks. On the ground, nests can be raided by mammals like foxes and rats. 

These predators are particularly problematic during the breeding season when eggs and chicks are most vulnerable.

During the breeding season, it is not uncommon to see protective behaviours displayed by terns. They are known to aggressively defend their nests, dive-bombing and mobbing potential threats. 

If you ever find yourself near a tern colony, you might witness these defensive actions firsthand, which are both impressive and a bit intimidating!

Where Can I See Common Terns In The UK?

In the UK, common terns are often seen along the coastlines and at inland water bodies during the breeding season. 

Key sites include the Norfolk coast, the Farne Islands, and various nature reserves managed by conservation organisations. These areas provide safe nesting grounds and abundant food supplies for the terns.

Visiting these sites offers a fantastic opportunity to observe common terns in their natural habitat. Bring a pair of binoculars, and you might catch a glimpse of their remarkable fishing techniques or hear their distinctive calls. 

Many of these locations also provide guided tours, enhancing your understanding of these captivating birds!

SEE ALSO: Common Tern Life Cycle: Nest Building To Fledging (and everything in between)

Frequently Asked Questions

How long do Common Terns live?

Common Terns typically live for around 10 to 20 years. 

How far do Common Terns migrate?

Common Terns migrate impressive distances, often travelling up to 25,000 kilometres round trip between their breeding and wintering grounds. 

Are Common Terns noisy birds?

Yes, Common Terns are indeed noisy birds, often heard making loud, sharp calls, especially during the breeding season.

Do Common Terns nest in the same place every year?

Common Terns often return to the same nesting sites each year, exhibiting strong site fidelity. 

How do Common Terns protect their nests?

Common Terns protect their nests by aggressively defending them, dive-bombing and mobbing potential predators to deter them. 

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