Birda Logo
Species Guide
A photo of a Forster's Tern (Sterna forsteri)
Forster's Tern

Forster's Tern

Sterna forsteri

The Forster's Tern (Sterna forsteri) is a medium-sized tern with a slender silhouette, characterized by a deeply forked tail and relatively elongated legs. In its non-breeding attire, it sports a white crown with a distinctive black, comma-shaped patch around the eye and ear-covert. The wings are a soft grey, with the primaries a darker shade of silver-grey, and the underparts are a pristine white. The bill is black, and the legs are a muted brownish-red. Come the breeding season, the tern dons a striking black cap that extends down the neck, pale grey wings and back, and a bright white underside. Its bill transforms to a black-tipped orange, and the legs become a vivid orange. Juvenile Forster's Terns resemble the winter adult but may have darker primaries.

Identification Tips

In breeding plumage, Forster's Terns can be distinguished from the similar Common Tern by their grey-centered white tails and pure white upperwings, lacking the darker primary wedge seen in the Common Tern. The non-breeding plumage features a white forehead and the persistent black eye mask, which aids in distinguishing it from other terns in winter.


Forster's Terns are marsh inhabitants, favoring freshwater, brackish, or saltwater environments. They are typically found over shallow open waters deep within marshes, including estuaries, islands, and salt marshes, as well as marshy areas around lakes and streams.


This North American species breeds inland and winters south to the Caribbean and northern Central America. It is a rare but annual visitor to western Europe, with occasional wintering in Ireland and Great Britain.


Forster's Terns are shallow plunge-divers, often hovering before diving headfirst with partially folded wings to capture prey. They are colonial nesters, fiercely competitive for nesting sites, often with gulls. The species is known for its aggressive defense of its nest and young, and both parents are involved in brood care.

Song & Calls

The Forster's Tern emits a descending 'kerr' call commonly, and a low, harsh 'zaar' when threatened. During courtship, the female may use a succession of 'kerrs' as a begging call.


Breeding season varies by location, starting as early as April on the Gulf Coast. Forster's Terns nest colonially, with clutches typically containing 2 to 4 eggs. Incubation lasts about 24 to 25 days, and chicks are semi-precocial, leaving the nest within days post-hatching to seek denser vegetation cover. Fledging occurs around 28 days after hatching.

Similar Species

The Forster's Tern is most similar to the Common Tern but can be differentiated by its winter plumage's black eye mask and the lack of a darker primary wedge on the upperwings in breeding plumage.

Diet and Feeding

The diet primarily consists of fish, with species varying by habitat. In freshwater, they may consume carp, minnows, and sunfish, while in brackish or marine habitats, pompano and herring are common. They also consume insects and occasionally crustaceans and amphibians.

Conservation status

The Forster's Tern is currently listed as Least Concern by the IUCN. However, habitat degradation and disturbances from boating and excessive noise pose threats. It is protected under the Migratory Birds Treaty Act in the U.S. and has varying conservation statuses in different states. Preservation of wetlands and artificial nesting sites are strategies being employed to mitigate risks to the species.

Forster's Tern Sounds

Recorded by: © 
App logo
Birda is a birdwatching app and community aimed at curious people who want to deepen their connection with nature.

Forster's Tern Fun Facts

Did you know?
Forster's Terns winter the furthest north out of all the North American Terns species.

Forster's Terns on Birda


More Gulls, Terns, Skimmers

Birda Logo

Your birdwatching journey like never before

Connect with nature in minutes
Take a walk, look out of the window and log the birds that you see. Feel good about those little connections to nature.
Discover the joy of birding
Find new birding spots, see more birds, share and celebrate with a like-minded community of nature lovers.
Play your part in saving nature
Logging your birding sightings and sessions turns into positive action for our planet. Every sighting counts.

Birda Blog

What Our Birders Say
Simply fantastic
I love this app, it puts so much fun into recording the birds I’ve seen and heard while I’m out and about. The interface is user-friendly and suitable for all ages. It’s great to collect badges and to review my “lists”.
Alex J
Friendly and helps to identify birds
Great birding app, good for logging your sightings, also has nice species guide. I'm enjoying the social aspect more than I expected, everyone seems friendly and helps to identify unknown birds. Good mix of newbies and experienced users.
A mordern game changer
Birda is an awesome app, its updated the world of birding to the modern day with a fun and easy to use app. It’s engaging and allows positive interaction with fellow bird lovers!
Unbridled Discoveries
Great app for bird lovers
I love this app! It’s a wonderful way to track birding sessions, and also connect you with fellow birders. I also really like the unidentified bird section, it’s a great community tool to help figure out what a never-before-seen bird is!
Amylia S
Best app for any birding person!
I love this app!! I am so addicted to it when I saw it had 3 star review I was so sad! The app is awesome!! The best app for any birding person! ❤️
Stewart W
Fantastic to be involved
Fantastic to be involved, great for mental health and gets you responding with the Challenges that are to takd part in.
Jane N
A great app
Enjoying it immensely and finding it useful too. Recording the different birds and counting them is showing me how the present climate is affecting them all. I've trebled the numbers by planting native hedging. A great app.
Hip An
Really enjoying Birda where I live i have a lot of Red kites really hard to photograph but I can video are you planning some place on the app where us Birda can post vids🦉🦅
Love Birda
I love this app. It really encourages you to log your sightings and the community is friendly and helpful.
Great app for learning Birds
I’ve been using the app for a couple of months and love it....Someone said it’s like a real life Pokémon Go for birds. They’re not far off! It’s something that the family can do that gets you out and about. Well worth downloading no matter your age.
As featured in
Birda Logo
AboutPressAmbassadorsAffiliatesInfluencersCareersPrivacyTerms & Conditions
An app for birdwatchers
Connect with us
Copyright © 2024 Chirp Birding. All rights reserved.