Black-tailed Gull (Larus crassirostris)

Black-tailed Gull – A Character Bird on Japan’s Coasts

The Black-tailed Gull (Larus crassirostris) is a striking coastal bird with a yellow beak and black tail band – common but sensitive in population.

Table of Contents

Introduction

Bold, alert, and always present: The Black-tailed Gull is a coastal bird with a recognizable appearance. While other gulls squawk, vanish, or keep their distance, this one is always in the middle – whether on harbor quays, in fishing bays, or on cliff islands.

Its bright yellow beak with red and black spots, along with its contrasting flight pattern, makes it a true character type among East Asian gulls.

Appearance and Features

The Black-tailed Gull is medium-sized – about the length of a tennis racket – and robustly built.

Typical Features:

• Head and underside: Bright white
• Back and upper wings: Light gray
• Wing tips: Dark with white “windows”
• Tail: White with a wide black band
• Beak: Strong yellow, with red and black spots at the tip
• Legs: Greenish-yellow
• Eyes: Bright with a fine red ring around the lid

In the air, it displays a striking flight pattern with contrasting wing tips and the black tail band.

Habitat and Distribution

The Black-tailed Gull is widely distributed along Japan’s coasts – and is a year-round companion.

Presence:

• Honshū, Shikoku, Kyūshū, occasionally also Hokkaidō
• Year-round presence, especially in mild coastal regions

Preferred Areas:

• Harbors, beaches, fish markets, cliff islands
• Inland waters, river mouths
• Also commonly seen in urban areas

It is not shy of humans – on the contrary, it often benefits from them.

Diet and Behavior

The Black-tailed Gull is an omnivore with a clear tendency for convenience. It takes what it finds:

Food Sources:

• Fish, crabs, snails
• Food scraps, fish waste, garbage
• Also carrion or eggs of other birds

Hunting Techniques:

• Catches food in flight
• Searches on the ground or on water
• Picks food out of gaps, nets, or waves

It follows fishing boats and waits in harbors for food – often with other gulls of the same species.

Breeding Behavior and Colonies

Breeding begins in May. Black-tailed Gulls breed colonially, often on remote cliffs or islands.

Breeding Details:

• Nest: Shallow depression, lined with plant material
• Clutch Size: 2 to 3 eggs
• Incubation Period: Around 24 days
• Both parents incubate and care for the chicks
• Chicks are precocial, but still cared for by parents

Especially well-known: The colony on Kabushima – a landmark for the species, deeply embedded in Japan’s cultural memory.

Migration Behavior and Seasons

The Black-tailed Gull is mostly sedentary, but shows regional migratory behavior:

• Year-round in many coastal regions
• Migration movements during strong winter conditions or food shortages
• Often small groups migrating along the coast

Flexibility is part of its success.

Population and Conservation Status

The Black-tailed Gull is common in Japan – but like many colonial breeders, it faces challenges:

• Disturbances at breeding sites (tourism, development) can be regionally problematic
• Still: No urgent conservation needs

It is adaptable, assertive – a robust part of Japan’s coastal ecosystem.

Descriptive Summary for the Visually Impaired

Imagine a medium-sized gull with a white head, light chest, and a soft gray back. Its wings are dark at the tips, with small white highlights at the ends – like shiny points.

Striking is the strong yellow beak, with a red and black spot at the tip – as if two drops of paint were applied.

Its legs are yellowish-green, and its eyes are bright, surrounded by a fine red eyelid ring, giving it an alert look. The tail ends in a broad black band – like it was drawn with ink.

It stands confidently on quays, rocks, or marketplaces – often near people.

FAQ – Frequently Asked Questions