Michaelmas Cay

About Michaelmas Cay

A low lying vegetated sand cay encircled by a spectacular fringing reef, Michaelmas Cay is a National Park and a protected sanctuary for migratory seabirds.

Michaelmas Cay is a small, vegetated sand cay:

  • Located on the western tip of Michaelmas Reef 43km north-east of Cairns and 17km north of Green Island.
  • The vegetated coral reef island covers an area of 1.8 hectares and rises to a height of 3.5m above sea level.
  • Around 360m long x 50m wide.

For a period during the late 1800s and early 1900s the island was used by sea cucumber pickers (Beche-de-mer) and for guano mining. In 1937 it was declared a fauna sanctuary and formally a national park in 1975. The Cay has cultural significance to the local Gungandji, Mandingalbay-Yidinji and Yirriganydji indigenous peoples.

How the Sand Cay formed

Michaelmas Cay was formed by the accumulation of broken coral, shells and remains of calcareous algae, continually washed over the reef by currents. Seeds deposited by visiting birds over time, and the resulting vegetation, helped to stabilise the cay. The formation of beach rock (sand and other reef remnants cemented into a rock by the action of algae) further stabilised the cay. The seeds carried in by the birds and the waves help vegetation flourish which in turn provides an ideal habitat for the seabirds to roost and nest.

A rich marine life

The Cay is rich with a myriad of sea life including green sea turtles (which occasionally nest on the cay), molluscs and invertebrates of all kinds and hundreds of species of tropical reef fish including Humphead Maori Wrasse. The reef surrounding the Cay is especially renowned for its abundance of giant clams.

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Cay Flora

The Cay’s vegetation is low growing and composed of grasses including sand spinifex Spinifex sericeus, stalky grass Lepturis repens and other cover such as goat’s foot vine and bulls head vine and Sea purslane Sesuvium portulacastrum.


A Protected Bird Sanctuary

Michaelmas Cay is a major natural seabird habitat and one of the most important in the Southern Hemisphere. It is home to at least 23 species of seabirds. Many breeds find this island an ideal nesting habitat and is one of the most significant bird sanctuaries on the Great Barrier Reef. At the height of nesting and breeding season (during Summer months) up to 20,000 birds have been observed. Breeding activity occurs throughout the year, most of the seabird species breed annually, Sooty Terns breed every 8.5 months.  


Birds of Michaelmas Cay

Sooty Tern

Sooty TernOnychoprion fuscata

  • Length around 33-36cm.
  • One of the largest numbered and most common seabirds found at Michaelmas Cay.
  • Colours: Dark black upperparts and white underparts. Black beak and black legs. Has similar colouring and pattern to the Bridled Tern.
Common (Brown) Noddy

Common (Brown) Noddy Anous stolidus

  • One of the most commonly seen birds on Michaelmas Cay.
  • From the Tern family.
  • The largest of the noddies, it can be told from the closely related Black Noddy by its larger size and plumage, which is dark brown rather than black.
  • A single egg is laid by the female of a pair each breeding season.
  • Colours: Whole body covered in dark black-brownish feathers except white marking around eyes and head.
Crested Tern

Crested Tern Thalasseus bergii

  • One of the most commonly found birds at Michaelmas Cay.
  • Length, 46-49cm long.
  • They feed by plunge diving for fish, the male offers fish to the female as part of the courtship ritual.
  • Colours: Grey upperparts, white underparts, a yellow beak, black legs and a shaggy black crest cap which recedes in winter.
Lesser Crested Tern

Lesser Crested Tern Thalasseus bengalensis

  • Length, less than 40cm.
  • Similar look to Crested Tern but smaller in size and an orange beak instead of yellow.
  • Distinctive black cap but smaller than the Crested Tern.
  • Breeds on Michaelmas Cay during Summer (October - December). One of the most commonly found birds here.
  • Colours: Grey back, white underparts
Black naped Tern

Black naped Tern Sterna sumatrana

  • Length, about 30 cm long with a wing span of 21–23 cm
  • Their beaks and legs are black. They have long forked tails.
  • Colours: White face and breast with a greyish-white back and wings. Black markings at the back of neck. The first couple of their primary feathers are grey.
Brown Booby

Brown Booby Sula lecogaster

  • Length 75cm, wing span up to 1.4 metres. Females larger than males
  • Dives from over 40 metres into the water to catch fish.
  • Females have a blue spot in front of eye.
  • Beak stout and straight.
  • The name “Booby” comes from the Spanish word “bobo” meaning fool because sailors thought these birds were stupid.
  • Colours: Dark brown and underparts white with brown throat.
Greater Frigate Bird

Greater Frigate Bird Fregata minor

  • A large seabird 85 - 105 cm in length with a wingspan over 2 metres.
  • Males are smaller than females.
  • These ‘pirates of the sky’ often chase and harass other seabirds to steal their food.
  • Colours: Males are black with scapular feathers that have a green iridescence when they refract sunlight. Females are black with a white throat and breast and have a red eye ring.
Caspian Tern

Caspian Tern Sterna caspia

  • The Caspian Tern is the largest in Tern family.
  • Length of 48–60 cm and a wingspan of 127–145 cm.
  • Black legs, a thick red-orange beak with a small black tip.
  • Colours: Upperparts are pale grey; Black cap and white neck and underparts.
  Gull Billed Tern

Gull Billed Tern Sterna nilotica

  • The Gull Billed Tern has a thicker beak than other Terns.
  • Length, 33–42 cm.
  • Black cap, strong black beak and black legs.
  • Colours: Grey upperparts, white underparts.
Eastern Reef Heron

Eastern Reef Heron Egretta sacra

  • Medium-sized herons, reaching 57 - 66 cm in length.
  • Reef herons come in two colours – white and grey. Although they look different, they are the same species. It is a lot like humans having either blue or brown eyes.
  • These birds are ambush hunters, able to stand still at the water’s edge for long periods waiting for prey (crabs, fish). They use their beaks to stab the prey, then they toss the food into the air and swallow it (fish are always swallowed head first to avoid choking on spiky fins).
Ruddy Turnstone

Ruddy Turnstone Arenaria interpres

  • These small shorebirds migrate every year from the Arctic Circle to the Great Barrier Reef. Seen from September - April.
  • Their name comes from using their beaks to flip over rocks and shells to look for food such as worms, sand fleas and small crabs to eat.
  • Less than 23cm long, black beak, orange red legs.
  • Colours: Upper parts greyish brown with white lower back and rump; Underparts: white, dark throat.
Little Tern

Little Tern Sterna albifrons

  • A small tern, 21–25 cm long.
  • Like most other white terns, the Little Tern feeds by plunge-diving for fish, the offering of fish by the male to the female is part of the courtship display.
  • Some group of these birds fly between Japan and Australia.
  • Orange legs, yellow beak.
  • Colours: Grey wings, white underparts. Looks like its wearing a black hood on its head.
Roseate Tern

Roseate Tern Sterna dougalli

  • A small-medium tern, 33–36 cm long.
  • In summer/mating season, the underparts of adults take on the pinkish tinge which gives this bird its name.
  • Red beak and legs, long tails.
  • Colours: Wings are pale grey and its under parts white.
Black Noody

Black Noody Anous minutus

  • The Black Noddy is a seabird from the Tern family.
  • t resembles the closely related Brown or Common Noddy but is smaller with darker plumage, a whiter-greyish cap, a longer, straighter beak and shorter tail.
Silver Gull

Silver Gull Larus novaehollandiae

  • Less than 42 cm long.
  • Present all year and commonly seen along coastlines.
  • Omnivorous Scavengers. They often steal eggs of terns and from unprotected nests.
  • Colours: White body with bluish grey back and wings. Red beak and legs

Note: Access to Michaelmas Cay is only allowed between 9.30am and 3pm daily and is limited to the restricted access area marked out by rope. 

Michaelmas Cay Maps

Michaelmas Cay is a small, charming reef sand island that is perched on the western tip of Michaelmas Reef 43km north-east of Cairns.

Link to Michaelmas Cay on Google Maps

Michaelmas Cay Map

Reef Fleet Terminal, 1 Spence St. Cairns, Queensland.
Australia, 4870 
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Email: [email protected]
Phone: (+617) 4044 9944