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28 Swallow-tailed Gull Facts: World’s Only Fully Nocturnal Gull and Seabird

Posted in: Ecuador Animals, Ecuador Travel, Galapagos Animals, Galapagos Islands

Curious to learn about these nocturnal seabirds with night vision? In this post, you’ll learn 28 facts about the swallow-tailed gull, found primarily in the Galapagos Islands. We include diet, size, mating, range, and how they manage to hunt at night. Plus, just what do their red eye rings mean? Let’s get started!

swallow tailed gulls nocturnal
Travel tip: If you’re traveling to the Galapagos, you should bring a camera with a good zoom and a decent pair of binoculars. This will increase the odds of spotting and shooting a swallow-tailed gull in the wild.

Guide to Swallow-tailed Gulls (Creagrus furcatus)

Did you know that the swallow tailed gull is the only nocturnal gull in the world? That’s not the only unique fact about this sea bird.

It also lives in the Galapagos Islands and changes its physical features when it’s breeding. Keep reading to learn all 28 Galapagos swallow-tailed gull facts.

Swallow-tailed Gull Overview

  • Latin Name: Creagrus furcatus
  • Range: Galapagos Islands, coasts of Ecuador, Peru, Colombia and Chile
  • Population Status: 35,000+ individuals
  • Size: Height: 20 to 22 inches (51 to 57 cm); Weight: 22 and 28 ounces (610 to 780 g)
  • Wingspan: Wingspan: 51 inches (130 cm)
  • Diet: Squid and small fish
  • Physical Features: Changes colors of head and eyering when breeding
  • Where it lives in Ecuador/Galapagos: Eastern side of the Galapagos Islands, favoring its warmer waters.
pair of swallow tailed gulls

1. Where does the swallow tailed gull live?

The swallow-tailed gull is endemic to the Galapagos Islands and can be seen nesting in colonies on most of the islands of the archipelago.

2. What is the range of the swallow tailed gull?

When the swallow tailed gull is not breeding on the Galapagos Islands, it heads out to live on the open ocean, flying and hunting for fish and squid. It will fly as far as the coasts of Ecuador, Peru, Colombia and Chile.

3. What is the habitat of the swallow tailed gull?

Second to the ocean, the swallow tailed gull prefers a habitat of steep, rocky slopes and cliff ledges, usually along the eastern side of the Galapagos archipelago.

4. Where do swallow tailed gulls nest?

Since swallow tailed gulls love the ocean so much, they nest in colonies along the shoreline on the eastern side of the Galapagos Islands. They’re found nesting throughout the year, especially on the cliffs and rocky beaches of Wolf, Hood, Tower, and Genovesa islands.

Unusual nesting habits are among the more interesting of swallow tailed gull facts. For example, it’s the male who claims the nest site and builds it before he chooses a female. The nicer the nest, the better chances he has of attracting a mate.

The male may choose a site on a graveled beach under bushes, a cliff platform, or lava ledge that is well-spaced apart from other nests. He then constructs the nest from pebbles, coral, lava pieces, and sea urchin spines. These materials are chosen because they will protect the egg from rolling away.

After the male has built his nest, he then shapes it by pressing his breast into the middle or by sitting in it and rotating on it. When he’s finished, the male is ready to attract his mate and start a family of three.

Both parents will guard the nest during the day, taking turns with brooding duties. At night, the non-brooding parent will fly out to sea and hunt for fish and squid to bring back to the nest.

5. What does the swallow tailed gull look like?

The swallow tailed gull is a medium- to large-sized gull with a long, forked tail and long, pointed wings. Their breeding biology really makes these gulls stand out from all the rest of the seagull species.

  • Breeding adults are distinctive for their black head, red eyering, pearly gray plumage, and pink legs and webbed feet. Their hooked bill is black with a gray tip.
  • In contrast, non-breeding adults feature a white head, black eyering, and paler legs and feet.
  • Juveniles look similar to non-breeding adults, except that they have white legs and brown spots on their backs.

Swallow tailed gulls also have large brown eyes that help them see fish and squid just under the surface of the water while flying high above in the sky.

6. How does the swallow-tailed gull see at night?

The swallow tailed gull has night vision. This is thanks to two factors.

  1. Their eyes are largest (both in size and volume) of all gulls.
  2. They have a special layer of tissue (known as tapetum lucidum) that reflects light back through the retina, allowing it to see better in low light, even dark, conditions.

7. How tall is the swallow tailed gull?

The adult swallow tailed gull reaches an average height of 20 to 22 inches (51 to 57 cm).

8. How much does a swallow tailed gull weigh?

A swallow tailed gull weighs between 22 and 28 ounces (610 to 780 g).

9. What is the swallow tailed gull wingspan?

The average wingspan of a swallow tailed gull is 51 inches (130 cm).

10. How did the swallow tailed gull get its name?

Adolphe-Simon Neboux, a French surgeon and naturalist, was the first person to officially describe the swallow tailed gull in 1846 after his visit to the Galapagos Islands.

  • Because it’s hooked bill brought to mind a hook that butchers used for holding meat, the gull was given the name Creagrus, which is a Latin word meaning butcher or meat.
  • The furcatus part of its name comes from the Latin word “furca,” which means “two-tined fork.”
Baby swallow-tailed gull

11. Are swallow tailed gulls friendly? 

Just like so many of the other birds and animals that are endemic to the Galapagos Islands, swallow tailed gulls are not afraid of people. You can walk right by one, and it won’t fly away. So, they aren’t aggressive toward people.

But, during the breeding period, the gulls will demonstrate aggression toward one another by displaying their bright red gapes or making jerking movements. Males will fight others over prized nesting sites, and females will compete with each other over males with the best nests.

12. How long do swallow tailed gulls live?

It’s not certain how long swallow tailed gulls live, but other seagulls have a life expectancy of up to 49 years.

It has been established that they begin to breed at 5 years of age.

13. What eats a swallow tailed gull? Predators and Threats

The main predators of the swallow tailed gull are raptors such as the Galapagos hawk, which could eat the gull itself but usually eat the gull’s egg.

Climate change, severe weather, and extreme temperatures are factors that may threaten swallow tailed gull populations.

14. Are swallow tailed gulls extinct?

No, swallow tailed gulls are not extinct. In fact, no endemic birds of the Galapagos Islands have ever gone extinct.

15. Is the swallow tailed gull endangered?

No, the swallow tailed gull is not endangered. While it’s population is estimated around 35,000 individuals over a small geographic area, its numbers don’t appear to be declining.

For this reason, the IUCN categorizes the swallow tailed gull as “Least Concern.”

16. What do swallow tailed gulls eat?

The world’s only nocturnal gull, the swallow tailed gull, preys at night on squid and small fish that swim to the surface to feed on plankton.

It is thought that this species learned to feed at night to avoid their prey from being stolen by frigatebirds.

17. How do swallow tailed gulls hunt?

At dusk, a colony of swallow tailed gulls heads out to sea together as a flock, often making a lot of screaming noises. They fly several miles out over the surface of the water, using their excellent night vision to hunt.

When they locate prey, they dip down and grab it in their bills. They also sometimes will sometimes take a break from flying and will swim on the surface, searching for prey.

18. What is the swallowed tail gull’s Latin name?

  • Class: Aves
  • Order: Charadriiformes
  • Family: Laridae
  • Subfamily: Larinae
  • Genus: Creagrus
  • Species: C. furcatus

19. What other names does the swallow-tailed gull have?

Because the swallow tailed gull has a forked tail, it is sometimes referred to as the fork-tailed gull.

20. Do swallow-tailed gulls mate for life?

It’s not certain if swallow tailed gulls mate for life or not, but pairs do tend to stay together from year to year.

Courtship and Mating Rituals of the Swallow-Tailed Gulls

Watch on YouTube

21. Why do swallow-tailed gulls eye rim change color?

The eye ring (or rim) changes color to indicate when it is in breeding season.

  1. Breeding season: Bright red, fleshy ring on each eye
  2. Rest of the year: black, flat eye ring

Here’s what their eye looks like during mating season.

swallow-tailed gull facts

22. At what age do swallow tailed gulls lay eggs?

Swallow-tailed gulls begin laying eggs when they reach their reproductive age of five years old.

23. How often do swallow tailed gulls lay eggs?

Swallow-tailed gulls have a reproductive cycle that’s approximately nine months, but they can breed at any time of the year. If an egg is unsuccessful or a chick dies, the gulls may try again much sooner than nine months.

Also, not all swallow tailed gulls breed at the same time, so there are always some mating pairs found breeding year-round.

Young swallow tailed gull

Thinking about visiting the Galapagos Islands? Here’s why you should visit.

24. How many eggs does the swallow tailed gull lay? Appearance?

A swallow tailed gull lays only one egg per breeding period. The egg is a buff color with brown specks.

Both parents will take turns incubating the egg for about 35 days. Even after the chick hatches, the parents will feed it for about three months when it’s old enough to fly out over the sea by itself.

25. What is the swallow tailed gull call?

  • The swallow tailed gull has a few different vocalizations, but the most common is an alarm call that is known as the “rattle and whistle.” The gull makes this sound when it senses a threat and produces this call with a gurgling scream while moving its head from side to side. When one gull makes this alarm call, others will join in with it.
  • Swallow tailed gulls greet one another with a loud, fast “kweek, kweek, kweek.”
  • Chicks will scream with a harsh call that displays their red gape.
  • These gulls are also known to make an odd clicking sound that researchers believe is used for echolocation when feeding at night.

26. Are swallow tailed gulls loud?

Swallow tailed gulls are indeed loud, especially when they are ringing out their “rattle and whistle” alarm call. When one gull sounds off the alarm, it’s contagious, causing all the others to join in with one big chorus.

27. Do swallow tailed gulls carry disease?

Swallow tailed gulls can carry diseases that include salmonella, Avipoxvirus, and avian malaria as well as infections caused by lice and parasites.

Fortunately, there are several research teams from the Galapagos Islands and around the world that work together to monitor and prevent the spread of bird diseases on the archipelago.

28. Where can I see the swallow tailed gull?

The swallow-tailed gull is found on the rocky shorelines and cliffs throughout most of the Galapagos Islands, but they are best seen on the islands of South Plaza, Española, and Genovesa.

A Galapagos Island cruise may take you around these islands where you can view thousands of swallow tailed gulls.

Swallow tailed gulls Galapagos

Learn more about other animals of the Galapagos Islands.

If you visit the Galapagos Islands, you should bring a waterproof bag to protect your camera and documents. Here are the best waterproof dry bags for your upcoming trip.

Your Turn

Like so much of the fauna living on the Galapagos Islands, the swallow tailed gull is a fascinating creature.

Were you surprised by any of these swallow tailed gull facts? Have you ever been on a cruise to the Galapagos Islands or seen this gull in person? Share your thoughts and experiences in the comments section.

Meet the Author

Dena Haines is co-editor of GringosAbroad - Ecuador's largest blog for expats and travelers. She is a travel blogger and content marketer. She is also co-founder of ClickLikeThis (GoPro tutorial blog) and Storyteller Media (content marketing for travel brands). Work with GringosAbroad.

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