Roseate Tern Vs Sandwich Tern: Key Differences Explained

There are a number of similarities between Roseate Terns and Sandwich Terns which can make identifying them difficult especially if seen from a distance. They are both members of the Sternidae family and have many common features.

However, there are enough differences between these two birds to help differentiate between them. Keep reading to find out how.

Key Takeaways

• Sandwich Terns are larger and more robust looking than Roseate Terns
• During the breeding season Roseate Terns have a pinkish hue to their breasts and underparts
• The black bill of the Sandwich Tern is tipped with yellow
• The black bill of the Roseate Tern has a red base during the breeding season
• Sandwich Terns have a shaggy black cap and crest

What Is The Difference Between A Roseate Tern And A Sandwich Tern?

Whilst Roseate Terns and Sandwich Terns share some similarities, they also have distinct characteristics that set them apart. These differences include;

Visual Differences

Sandwich Terns are larger and more robust looking birds than Roseate Terns. They are mainly white with pale grey upper wings and backs, black cap, a yellow tipped, long, slender black bill, black or dark grey legs and a slightly forked tail.

Roseate Terns are smaller and more delicate looking with pale white appearance with a pinkish tinge to the breast (particularly during the breeding season), long, narrow wings with pale grey upperparts and lighter coloured underparts. They have slender, sharp all black bills (which can have a red base during the breeding season), bright red or orange legs and a long deeply forked tail which extends way beyond the wing tips when perched.

During the breeding season, Roseate Terns develop a pinkish hue to their breasts and underparts which tends to fade as the season progresses.

The black cap of Sandwich Terns becomes much more prominent during the breeding season and the yellow tip on the bill is much more striking too. Plus the crown often appears more shaggy due to the long black crest feathers.

Differences In Habitat

Sandwich Terns are found all across Europe, Africa and the Americas and are typically found in estuaries, lagoons and sandy coastlines. They typically build their nests in open, flat areas without too much vegetation as this allows them to see any potential predators approaching the site.

Roseate Terns have a more restricted breeding range and are typically found on isolated islands and coastal areas in temperate zones. They prefer sandy beaches, rocky islands and saltmarshes as nesting sites.

They typically build their nests in areas with dense vegetation or tall grasses that provide cover for the nests. They will select sites that are hidden under shrubs or among rocks to help protect the nest and the chicks from predators.

Whilst both of these birds migrate to tropical and subtropical coastal areas, Roseate Terns are most likely to be found around coral reefs and lagoons. Whereas Sandwich Terns are more often found along sandy coasts and estuaries.

Nests & Eggs

Both of these Terns nest in large colonies of mixed species; in fact, Sandwich Terns and Roseate Terns often nest in the same colonies. Sandwich Terns are the more aggressive of the 2 and are more likely to defend their nests. Whereas Roseate Terns tend to be more secretive and less aggressive even when defending their nests.

Sandwich Tern eggs are white, pinkish or buff coloured and covered with dark brown speckles. They are oval shaped and around 51 x 36 mm in size. With an average weight of around 35 grams per egg.

Roseate Tern eggs can be found in various shades of brown with darker streaks and spots. They are roughly 43 x 30 mm in size and weigh around 20 grams.

Bird Calls

The calls of these 2 birds are very different with Sandwich Terns having a louder, more abrupt distinct call than the Roseate Tern. The call of the Sandwich Tern has a “kirrick” or “keerick” sound.

Roseate Terns have a softer, more melodious high-pitched call which sounds like “chuwit” or “chip-chip”.

Size & Weight

Sandwich Terns are the larger of the 2 species with an average length of around 36 to 41 cm and a wingspan of around 95 to 105 cm. They weigh anywhere between 210 to 260 grams and generally look more robust.

Roseate Terns have an average length of around 33 to 38 cm and a wingspan of around 72 to 80 cm. They can weigh anywhere between 95 to 130 grams and generally look a more delicate bird in comparison.

SEE ALSO: Arctic Tern Diet and Size: Feeding Habits, Predators, and Measurements

Frequently Asked Questions