Ian’s Bird of the Moment – Christmas Island Birds

Ian’s Bird of the Incident he’s called it this time in his newsletter. By Ian Montgomery
Well, I’ve finally emerged from various Christmas Island induced rabbit holes and we can have our virtual trip to look at some of the special birds of this remote island. There aren’t any feral rabbits on Christmas Island, so Red Crab burrows might be a better metaphor.
Christmas Island is both remote and very old, making it an interesting place in terms of both biogeography and avian evolution. It is about 350km/220 miles south of the western tip of Java and 1,550km/960 miles northwest of Exmouth in Western Australia. There are no nearby islands – the Cocos Keeling Islands are 980km/610 miles to its west. It first appeared about 60 million years ago as a 5,000m/ high volcanic seamount which then underwent several geological uplifts over the following 10 million years giving it a layered structure with cliffs, both coastal and farther inland, formed by coastal erosion. Coral reefs deposited limestone over the basalt core.
60 million years ago was shortly, geologically speaking, after the extinction event, thought to be a global collision with a large object, about 66 million years ago that marked the end of the Cretaceous period. This caused the extinction of many plants and animals, notably the dinosaurs, and resulted in rapid adaptive radiation of many surviving groups, particularly birds and mammals. At the time Australia was still attached to Antarctica and the other tectonic plates of the former Gondwana were still drifting to their current locations and resulting land masses: South America, Africa, Madagascar and India.
The island has an area of 135 sq km/52 sq mi and the coast is an almost continuous cliff with few bays or beaches, as shown in the photo of the east coast. Although known to European sailors from the 17th century, the cliffs made landing, exploration and settlement difficult and it remained uninhabited and consequently undisturbed until the late 19th Century. The largest bay is Flyingfish Cove near the north of the island where the Settlement is located. The photo below shows a typical stretch of coast looking south from Margaret’s Knoll on the eastern side of the island.
You’ll probably know from previous posts that I’m particularly interested in the evolution and ecology of birds, and by extension their taxonomy and biogeography. Isolated islands both provide fascinating insights into and pose intriguing questions about both evolution and biogeography and I’m going to look at the species on Christmas Island from these angles. We’ll start with the taxonomically most unusual, Abbott’s Booby, which belongs to a monotypic endemic genus, then look at other interesting seabirds and finish with land birds.
Three of the seven global species of Booby breed on Christmas Island: Abbott’s, Brown and Red-footed. Both the Brown and Red-footed are widespread, found throughout tropical waters around the world and members of the genus Sula which comprises all the species of Booby except Abbott’s.  Abbott’s, however, breeds only on Christmas Island and is the only member of the genus Papasula. It was originally included in Sula but structural differences between it and both Gannets and other Boobies led Olson and Warheit 1988 to move it to a new more primitive genus of its own. Subsequent DNA studies have confirmed this and Papasula is thought to have branched off the early Gannet-Booby lineage about 22 million years ago.
We can’t, however, conclude that it evolved in isolation on Christmas Island. The species was first described from a specimen collected by the American naturalist William Louis Abbott in 1892 on an island near Madagascar in the western Indian Ocean, either Assumption Island or the nearby Glorioso Island. Fossil evidence indicates that it was quite widespread in the Indian and Pacific Oceans and there are eyewitness reports of it breeding in the Mascarene Islands near Mauritius (as described in Wikipedia). So its endemic status on Christmas Island is a result of its extinction elsewhere. On Christmas Island the population, currently estimated at about 2,000 pairs, has declined owing to habitat clearance and the species is classified as endangered.
Here, by way of comparison, is the white morph of the Red-footed Booby. There is also a widespread brown morph of this species but all, or almost all of the ones on Christmas Island are of the white morph. You can see photos of the brown or dark morph here: Birdway Red-footed Booby.
Frigatebirds are very well represented on Christmas Island. Three of the five global species nest on the island: Lesser, Great and the endemic Christmas (Island) Frigatebird. The other two species are the Magnificent (Birdway: Magnificent Frigatebird) of Atlantic and eastern Pacific Oceans and the Ascension, endemic to Ascension Island in the Atlantic. The Lesser (Birdway: Lesser Frigatebird) has colonised Christmas Island in small numbers relatively recently while the Great (Birdway: Great Frigatebird) is an endemic subspecies (listeri) with a population of about 3,300 pairs.. The Christmas Frigatebird is globally the rarest with a population of about 1,200 pairs. The population has declined since human settlement and the species is now classified as critically endangered, both because of its small, declining population and the fact that its breeding range is limited to a single location.
Unlike Abbott’s Booby, it’s probably fairly safe to assume that it evolved on the island and differs from the other species of Frigatebird mainly in the patterning of the plumage. The male has a diagnostic white belly, while the female has a white breast and belly extending further down the belly than in other species.
Frigatebirds feed both by snatching prey such as squid and flying fish from on or near the surface of the water and by harrying Boobies, Tropicbirds and Terns until they drop their food. In the photo above, this female has just regurgitated a no doubt tasty mixture for its chick including a flying fish, the “wings” of which you can see sticking out on both sides of the chick’s mouth.
While we’re on the subject of tropical seabirds, Christmas Island has two of the three global species of Tropicbirds: the White-tailed and Red-tailed Tropicbird. Most of the local White-tailed Tropicbird population has black and apricot rather than the typical black and white plumage and has been ascribed to a separate subspecies fulvus. It is known locally as the Golden Bosunbird. However, 7% of the local population has the normal black and white plumage and apricot coloured birds occur in small numbers elsewhere, so it may be better to consider the differences just as colour morphs.
For me, the Golden Bosunbird was the most beautiful bird on the island and I spent hours watching them in flight from this lookout near the settlement overlooking Tai Jin House, below, the former resident of the governor in more colonial times.
The Red-tailed Tropicbird, or locally Silver Bosunbird, is quite beautiful too. In pristine condition, the birds have long red tail streamers, but these frequently get broken off when the birds are nesting. They do a spectacular fluttering display flight travelling downwards and often slightly backwards near the cliffs where they nest.
Both of these Tropicbirds are quite widespread. The White-tailed occurs in tropical parts of the Indian, Pacific and Atlantic Oceans while the Red-tailed ranges from the western Indian Ocean to the central Pacific.
Special birds on Christmas Island are not restricted to sea birds: it has some unusual land birds as well. Here is the splendid and abundant Christmas Island Imperial Pigeon.
The dorsal plumage is this lustrous green which reminds me of Connemara marble. The breast is plum-coloured, the vent rufous and the eyes are a spectacular golden. It’s endemic to the island and its closest relative is the Pink-headed Imperial Pigeon (D. rosacea), widespread in the Indonesian islands of the Java Sea.
A much more elusive member of this family is endemic race natalis of the Common or Asian Emerald Dove. This used to be treated as the same species as the Emerald Dove that occurs in Australia but the latter has been split into two species: the Common or Asian and the Pacific. As a result, Christmas Island is the only place in Australia where the Common or Asian species occurs.
Also elusive is the only resident owl, the endemic Christmas Island Boobook. With a length of 26-29cm/10-11.4in, it is generally smaller than the rather variable Australian Bookbook of the mainland: 27-36cm/10.6-13.8in. We went out one night near the golf course with David James, one of the leaders of the first Christmas Island Bird Week, who was armed with a recording of the call. The recording was of poor quality but to our delight and surprise we got a response and a family of three appeared at close quarters. The species is regarded as vulnerable with a population of maybe 500 pairs and there are concerns that the introduction of yellow crazy ants is affecting the availability of the invertebrate prey that is its main source of food.
Christmas Island also has an endemic diurnal predator, the Christmas Island Goshawk. Its taxonomy has proved a challenge for various taxonomists and it has generally been treated as a race of the Brown Goshawk (Accipiter fasciatus). In fact there are significant differences in structure, appearance and behaviour, so there is probably justification for treating it as a separate species. It is the rarest of the endemic birds with a population of probably less than 250 individuals. Unlike the Brown Goshawk, the birds are relatively tame and approachable.
Christmas Island has only two endemic Passerines, the endemic race of the Island Thrush that was the subject of the last Irregular Bird and the Christmas Island White-eye. White-eyes are famous for finding their way to and settling on remote islands so there are nearly one hundred species ranging from Africa through the warmer parts of Asia to Australasia and the islands of the Pacific. This one is posing on a coral tree near Tai Jin House.
So, there you are. Plenty of rabbit or red crab burrows to be explored by budding taxonomists and biogeographers. Talking about Red Crabs, itt wasn’t the right time of the year for the Red Crab spawning event and I don’t remember seeing any as they keep out of sight at other times of the year. We did encounter some Robber or Coconut Crabs, however. This species  is the largest terrestrial arthropod, weighing up to 4kg/8.8lbs and measuring up to 1m/39in in span from leg tip to leg tip. Their range comprises islands of the Indian Ocean and parts of the Pacific.
Greetings and stay safe,

Lee’s Addition:

“Thus the heavens and the earth were completed, and all their hosts. By the seventh day God completed His work which He had done, and He rested on the seventh day from all His work which He had done.” (Genesis 2:1-2 NASB)

Very interesting how these birds have developed and interbred over the centuries. With isolation, much interbreeding within the species has helped influence these varieties within the families and orders.

See More of Ian’s posts at:

Ian’s Bird of the Week

Who Paints the Leaves?

Ian’s Bird of the Week – Masked Booby

Masked Booby (Sula dactylatra) by Ian

Masked Booby (Sula dactylatra) by Ian

Ian’s Bird of the Week – Masked Booby ~ by Ian Montgomery

Newsletter – 5/20/11

We got a good view of a female Lesser Frigatebird at Lucinda on Wednesday when we did our regular wader count so I considered this species for bird of the week, forgetting that it had featured in March. So here is another spectacular seabird instead: the Masked Booby.

Masked Booby (Sula dactylatra) by Ian

Masked Booby (Sula dactylatra) by Ian

The first photo shows a portrait of a male bird, distinguishable from the female by its yellow bill. That of the female, second photo, has a greenish tinge to it. As you can see from these photos, Boobies are very approachable and the name comes from the Spanish ‘bobo’ meaning clown or fool as sailors found the birds easy to catch.

Masked Booby (Sula dactylatra) by Ian

Masked Booby (Sula dactylatra) by Ian

The difference between the sexes is subtle though the female is larger and they are easier to tell apart when seen together, like the pair in the third photo on a beach. Boobies and Gannets are very social and have sophisticated behaviours for display, territorial disputes and fishing so the ‘bobo’ label was a bit hasty.

Masked Booby (Sula dactylatra) by Ian

Masked Booby (Sula dactylatra) by Ian

All these photos were taken at East Diamond Islet, a remote cay on the eastern edge of the Barrier Reef in the Coral Sea Islands Territory, within Australia’s territorial boundaries but outside Queensland. This cay is typical of Masked Booby colonies, far offshore in tropical or sub-tropical waters, and the birds fish in deep water and are not normally seen close to the coast. The range of the Masked Booby is right around the globe and in Australasia there are colonies in northern Western Australia, northeastern Queensland, Lord Howe and Norfolk Islands and the New Zealand Kermadec Islands. The birds at the last three sites have black rather than yellow eyes and belong to a different race. Another race in the eastern Pacific with orange bills has recently been split off as a separate species the Nazca Booby.

Masked Booby (Sula dactylatra) by Ian

Masked Booby (Sula dactylatra) by Ian

Masked Boobies nest both on rocky cliffs and flat areas and the female in the fourth photo is sheltering a nestling and simultaneously expressing a verbal protest at being photographed. They usually lay two eggs, but the second is only an insurance policy and the first nestling to hatch will kill its sibling if it also hatches. Juvenile birds, fifth photo, look quite similar to the closely related Brown Booby but are distinguishable by having a complete white collar which in front forms a white rather than brown upper breast.

Masked Booby (Sula dactylatra) by Ian

Masked Booby (Sula dactylatra) by Ian

The sixth photo is of a male in flight and shows the black tail that distinguishes it from the white phase of the Red-footed Booby. Like all the gannets and other boobies, the Masked feeds by spectacular plunge-dives for fish, all members of the family have air sacs off the bronchi to absorb the impact – the original airbags. The Masked is the largest of the boobies (to 86cm/34in with a wing-span of 1.7m/5.5ft) and its maximum dive has been estimated at 100m/330ft though it’s smaller than the gannets. Gannets can reach 10m/33ft depth just from the dive and then swim down to 20-25m and usually take the target fish on the way back up.

Wednesday’s female Lesser Frigatebird
Nazca Booby
Brown Booby
Red-footed Booby

Here are a couple of points from earlier postings. Last week I had an email from Brett who reported the northern race of the Eastern Yellow Robin at St George’s Basin, 200km south of Sydney and well south of the documented range to the Hunter Valley. He – brett@brettdaviswebsitedesign.com.au – would be interested to hear from others who have recorded it south of its supposed range. A month ago (Yellow White-eye) I inquired about a plant with large fruits and pink flowers. The plant in question is calotrope (Calotropis procera) – thank you to the respondents – an introduced weed, but popular with native birds such as this Red-headed Honeyeater in Broome.

Best wishes,

Ian Montgomery, Birdway Pty Ltd,
454 Forestry Road, Bluewater, Qld 4818
Phone: 0411 602 737 +61-411 602 737
Preferred Email: ian@birdway.com.au
Website: http://birdway.com.au

Lee’s Addition:

The Sulidae – Gannets, Boobies Family has 10 species. The three Gannets are the Northern, Cape, and Australian. The seven Boobies are the Blue-footed and Red-footed, Peruvian, Nazca, Brown and the Masked Booby which Ian just wrote about. This family is part of the Suliformes Order which also includes the Frigatebirds, Cormorants, shags and the Anhingas, darters families.

Talking about the young one and the nest of the ground reminds me of:

If you come across a bird’s nest in any tree or on the ground, with young ones or eggs and the mother sitting on the young or on the eggs, you shall not take the mother with the young. (Deuteronomy 22:6 ESV)

The Blue-footed Booby – The Stupid Fellas

The Blue-footed Booby – The stupid fellas  ~  by a j mithra

Blue-footed Booby (Sula nebouxii) by Bob-Nan

Blue-footed Booby (Sula nebouxii) by Bob-Nan

The Blue-footed Booby (Sula nebouxii) is a bird in the Sulidae family which comprises species of long-winged sea birds… The natural breeding habitat of the Blue-footed Booby is tropical and subtropical islands off the Pacific Ocean most famously, the Galapagos Ecuador…

Blue-footed Boobies are distributed among the continental coasts of the eastern Pacific to the Galapagos Islands and California…

Blue-footed boobies are possibly one of the world’s most fearless birds! Indeed, lacking any instincts for fear and being quite clumsy on land make them easy prey for other animals. When Spanish settlers first encountered blue-footed boobies, they were amused by how easy it was to hunt these birds…

This is because the Blue-footed Booby is clumsy on the land. To make their point clear, Spanish settlers named this bird “bobo” which means “stupid fellows.”

If people call you “stupid”, just praise the Lord… For, God chooses the fools and the weak instead of the wise and the strong…

But God hath chosen the foolish things of the world to confound the wise; and God hath chosen the weak things of the world to confound the things which are mighty; (1Corinthians 1:27)

The booby’s eyes are placed on either side of their bill and oriented towards the front. They have excellent binocular vision. The Blue-footed Booby has permanently closed nostrils specialized for diving. They breathe through the corners of their mouths. When God created these birds, He knew that they need to dive deep for survival.. That is the reason that He took so much care in placing the eye at the right place and the closed nostrils , so that it does not drown…  Close up of a Blue-Footed Booby

Each one of us are different in size and structure and shortcomings.. But, when God created us, He had a definite plan.. Do you think that God would’ve chosen Moses if he was not stammering? Do you think God would’ve chose Rahab if she was not a harlot?

God changed their shortcomings into their strength to glorify His name… That is because their trust was in God.. If we trust God, He can change our weakness into our strength…

And he said unto me, My grace is sufficient for thee: for my strength is made perfect in weakness. Most gladly therefore will I rather glory in my infirmities, that the power of Christ may rest upon me. (2 Corinthians 12:9)

Blue-footed Booby (Sula nebouxii) by Bob-Nan

Blue-footed Booby (Sula nebouxii) by Bob-Nan

When blue-footed boobies are ready to breed, they carry out many interesting rituals. First, a male blue-footed booby parades around his nest area. The parade is anything but ordinary – just in case a female blue-footed booby fails to notice how attractive he is, the male blue-footed booby raises each of his blue feet in a slow, deliberate stepping motion.  Alternatively, if he is flying over his territory and encounters a potential mate, he flashes his blue feet at her as he lands. These male birds show off their blue feet to attract their female mates..

But, our Lord Jesus Christ turned ugly on the cross to show how much He loves us.. Can you not see His nail-pierced bleeding feet which came in search of us? So many time His presence has hovered over us, but, how much have we felt it?

For he shall grow up before him as a tender plant, and as a root out of a dry ground: he hath no form nor comeliness; and when we shall see him, there is no beauty that we should desire him. (Isaiah 53:2)

Then, both male and female blue-footed boobies point their long beaks toward the sky, tilt their wings around, and give their mating calls. The male blue-footed booby also makes a high-piping whistle noise.

During the courtship, they also pick up small stones or twigs as building materials for their nests, but, strangely, they undo their nests later on just about the time that the female blue-footed booby is ready to lay eggs. They are not a seasonally reproducing species but are opportunistic in their breeding..

The Blue-footed Booby is a monogamous animal although they do have the potential to be bigamous. They reunite at their breeding grounds…

We too are going to unite soon with the Lord…  Jesus is on His way to take His bride and to live with her forever and ever…  Is the bride ready for takeoff?

For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known. (1 Corinthians 13:12)

Blue-footed Booby (Sula nebouxii) by Ian

Blue-footed Booby (Sula nebouxii) by Ian

The Blue-footed Booby is strictly a marine bird and their only need for land is to breed, which they do along rocky coasts. They nest on bare black lava in a small dip in the ground. The female will turn to face the sun throughout the day so the nest is surrounded by excretion. The female Blue-footed Booby lays two or three eggs. Both male and female take turns incubating the eggs, while the non-sitting bird keeps a watch.

Since the Blue-footed Booby does not have a brooding patch, a patch of bare skin on the underbelly, it uses its feet to keep the eggs warm. Blue-foots are one of only two species of booby that raise more than one chick.

You may think that you do not have resources, like other to realize your dreams… But, all things are possible with God..

These female birds do not have a brooding patch, but still, they raise chicks with their feet and that too they raise more than one chick…

You may feel that you do not have beauty or talent or riches or influence to make your dreams happen…  When you have Jesus as your everything, nothing is impossible….

And he said, The things which are impossible with men are possible with God. (Luke18:27)

Blue-footed Booby (Sula nebouxii) larger chick by Bob-Nan

Blue-footed Booby (Sula nebouxii) larger chick by Bob-Nan

Blue-foots are one of only two species of booby that raise more than one chick. The males is specialized in diving in shallow waters. They must be fed frequently, so the adults constantly hunt for fish. The chicks feed off the regurgitated fish in the adult’s mouth. If the parent Blue-footed Booby does not have enough food for all of the chicks, it will only feed the biggest chick, ensuring that at least one will survive.

Blue-footed Boobies are specialized fish eaters feeding on school fish like sardines, anchovies, mackerel, flying fish, squid and offal. It dives into the ocean, sometimes from a great height, and swims underwater in pursuit of its prey. It hunts singly, in pairs or in larger flocks. They travel in parties of 12 or so to areas of water with large schools of small fish. When the lead bird sees a fish shoal in the water, it will signal the rest of the group and they will all dive together to catch the fish.

Like these birds, we as believers and church builders need to learn to dive together into the Living water..

These birds signals to the rest of the group when it sees a shoal of fish..

How many of us signal our co-workers when we see a blessing?

Please read 1 Kings Chapter 7, verse from 3…

You will know how God used four lepers to deliver his people from the enemies… How they shared the good news and signaled the others about the blessing which God had kept in store for them…

Surprisingly, individuals do not eat with the hunting group, preferring to eat on their own, usually in the early morning or late afternoon. They will point their bodies down like an arrow and dive into the water. Plunge diving can be done from heights of 33–100 ft and even up to 330 ft (100 m). These birds hit the water around 60 mph (97 km/h) and can go to depths of 82 ft (25 m) below the water surface. The prey is usually eaten while the bird is still under water. Males and females fish differently which could contribute to the reasons that blue foots, unlike other boobies raise more than one young.

The male is smaller and the tail is larger for its body which enables the male to fish in shallow areas instead of just deep waters. The tail can flatten out easier enabling him to change direction in the shallow water. The female is larger and can carry more food. The food is then regurgitated to the young. The males feed the young for the first part of the incubation period. This is done because the males can bring back food quicker than the female. When the demand for more food takes over the female provides the food to the young… These female birds are larger and carry more food…

Even our bridegroom Jesus Christ wants us to do more than what He had done… That is why He says,

Verily, verily, I say unto you, He that believeth on me, the works that I do shall he do also; and greater works than these shall he do; because I go unto my Father. (John 14:12)

Now never ever say that you can’t do this or can’t do that… We have been called to say that I can do all things through Christ that strengthens me, and also to do greater things than what Jesus did…


Have a blessed day!

Your’s in YESHUA,
a j mithra

Please visit us at: Crosstree

Red-footed Booby (Sula sula) by Bob-Nan

Red-footed Booby (Sula sula) by Bob-Nan

Lee’s Addition:
Boobies are part of the Sulidae Family of Gannets and Bobbies in the Pelicaniformes Order. There are actually 7 Boobies.
Abbott’s Booby
Blue-footed Booby
Brown Booby
Masked Booby
Nazca Booby
Peruvian Booby
Red-footed Booby