Sunday, 28 December 2014

Second chick leaves the nest

Got it wrong about both the babies leaving the nest together.  A very lonely and very hungry fig parrot chick was hiding in the nest hollow all of yesterday.  In the early morning I could hear timid calls.  The parents did not seem to want to go near it, rather coming and going every few minutes, flying circuits and landing in the canopies of nearby trees and all the while issuing lots of urgent ‘lets go’ calls.  An hour later this was still going on and the chick was looking quite distressed as though it was not capable of leaving the hollow and was now being abandoned to starve.  It is likely that the chick had not been fed for at least a day to help motivated it to leave the nest and perhaps to make sure that the chick was as light as possible for its maiden flight.  Things were starting to look hopeless as the chick lacked the confidence to leave and the parents would not feed the chick or even go close to it.
double-eyed fig parrot
Older sibling? and parent calling to the chick which is in the nest hollow behind the leaves.  Birds are out of focus.
Finally the parents managed to psyche the chick up.  They issued a call and the chick called back then issued another call and the chick responded.  Gradually they upped the tempo until the chick was calling for all it was worth but it still didn’t jump.   In a final desperate measure, the parents and chick that flew yesterday came down and alighted on a branch just in front of the nest hollow and the psyched up chick finally came out.  With a great rush, they all flew over to the dense and welcoming foliage of the weeping fig in a park across the street.

Can you see the chick?
In the fig, the chick made sure that the parents knew all about how hungry it was with the loudest begging from a fig parrot that I have ever heard.

Fig parrots depart the nest

One young double-eyed fig parrot nearly did not make it.  The black butcherbird had him and was flying off but the butcherbird fumbled the chick and I was able to recover it.   It helped that the butcherbird was looking in the garden for chick, otherwise I would not have known where the chick was.  I do not know how the butcherbird caught the chick and I suspect that the chick was on its first venture out of the nest.
Cracticus quoyi
Black butcherbird thinking about how to catch caged birds
A day before, I photographed the chicks in the nest hollow.  When you move near the tree, they hide, but if you stand still for a few seconds, they can’t resist having a look.  It must be very hot in the still air of the hollow and in the late afternoon they are almost gasping for cool outside air.

Hiding fig parrot chicks
They can't resist taking a look for long
I imagine that a number of predators that stalk my yard could have eaten the chicks. Carpet snakes, lace monitors, tree snakes, kookaburras and of course black butcherbirds make up the main threats. Tree-climbing rats could also be an issue at night.  All these animals are present in the Cairns suburbs, particularly the older suburbs with quarter acre blocks that are not far from swamp or rainforest.  In fact, in mid-October I viewed a large chick in the nest and this chick may not have made it.  Birds grow fast and I do not think that a chick that was large in October would be the same bird as the chicks which I watched in December but then I do not know much about fig parrots.

The recovered and unhurt chick
I put the lucky chick back in the nest hollow.  He went in and was silent for half an hour.  The parents had seen the black butcherbird take the chick and then a human jump a fence and catch the chick so they were quite upset.  They refused to go near the nest hollow but instead flew some high reconnaissance circuits around the nest tree and made loud alarm calls.  The unaffected chick was calling for food loudly.  Suddenly I saw three parrots fly directly from the area of the nest to the dense canopy of a nearby weeping fig.  I suppose that both chicks simultaneously flew the nest.  The chick I rescued and that could not fly at ground level could drop from the tree to pick up speed then fly fast and level.  After six months of watching this nest hollow, suddenly it was empty.

Search this blog for fig parrot to see more.

Friday, 12 December 2014

Mangroves in the Sky

Evolution of mangroves interests me and in this blog I have often written about the specific situations that may give rise to new mangrove species.  I am fairly convinced that mangrove soils are just as big a barrier to mangrove evolution as salinity.  The US Government actually maintains a database of salinity resistant plants with several thousand species in it so why don't these species dominate our shores?  What if plants could adapt to mangrove soils first and later learn to live in the intertidal zone where they are exposed to high levels of salinity?  Evolving in two steps rather than one might greatly reduce the entry barrier to mangrove evolution.  I know of a place where this process is possible, where mangrove soils have risen out of the sea and have become mountains of mud – Gulf Province in Papua New Guinea.

rainforest landslide
Small plateau with near vertical sides are common and landslides are frequent
At 125 m above sea-level and about 50 kilometres inland, I was looking at the stream banks and realised that the patterns in the rocks were the preserved burrows in marine invertebrates, probably yabbies and crabs and worms similar to those that are found in tropical estuaries today.  In fact the rocks are not even really rocks, they are just compressed sandy marine mud and you can break the rocks with your hands.  Trapped beneath about 2 km of this marine mud is the gas field that InterOil is developing.  It is the highest pressure gas field in the world as the soft mud is not self supporting like stone but transfers its full weight onto the gas below creating the highest lithostatic pressure of any production gas field in the world. This place really is a mountain of mangrove mud.

Testing the gas flow rate at the gas field - all the other photos were taken with a few kilometres of this place.
Photo from
On the crest of a nearby hill, soil development was less than a metre thick then almost unaltered grey marine mud
Fossil cockles could be found in some of the stream banks.  Many types of mollusc shell could be found but I could not find any crustacean body parts.  I began talking to local tribesmen to ask if they had ever seen any crocodile or sharks teeth in the ground and at that very moment, I found a megalodon tooth in the ground where we were standing.  Megalodon sharks were largest and most dangerous shark that ever lived and they lived between 1 and 25 million years ago, so I had an upper and lower limit for age of the fossils I was finding.

sub-fossil scallop and cockle shells
This looks like fresh dredge spoil but is actually sub-fossils that are millions of years old
Broken Megalodon tooth - Gulf Province PNG
Fossil marine animal burrows in river stones
Even after millenia, the mangrove mud had not lost its characteristic appearance.  Unfortunately I did not test it for salinity or hydrogen sulfide. Only a shallow band of reddish soil had developed even in the most aerated parts of the landscape.  In North Queensland, weathering has created soil profiles up to 30 m deep, even on recent volcanic lava flows so the contrast between the soils of tropical Australia and PNG is extreme.  Near the coast, there are also coral reefs that have been uplifted and are now coastal headlands.

So the gradual uplift of PNG has created a situation where marine substrates are lifted above sea-level and the character of the soils remains essentially marine for millenia.  In theory, plants could adapt to these soils over time and then be dispersed downstream to colonise the lower catchment and possibly even mangrove areas.  So are new mangroves evolving here?  I have not had the pleasure of looking the area over.  It is said to be full of pirates armed with automatic weapons so one can't just go there.  There is at least one mangrove species which is unique to this region, which suggests that it may have evolved there.  A word of caution though, rapidly rising and falling sea level over geological time has sent many mangroves species locally extinct and some mangrove species now only occur in areas away from their birth places.
Camptostemon schultzii
The mangrove (Camptostemon schultzii) only occurs on Cape York Peninsula and in the Gulf of Papua - could it have come from the uplifted marine deposits?
Camptostemon schultzii
Camptostemon mangroves have giant sized knob roots.
The extreme rainfall of Gulf Province, about 9 m per year prevents the soils from drying out and is probably the reason why there is mangrove mud in the mountains.  The mud has many consequences, mountain streams flow with turbid water, trees are shallow rooted and easily fall over.  When I was in the forest, a strong trade wind blew over the forest, perhaps 40 km/hr and big trees started to fall.  We had to leave the primary rainforest with the big trees and head for secondary forest which is regenerating after a landslip as the risk from big falling trees was considerable.  In north Queensland, trade winds blow for more than half the year and the big trees are unaffected.  Palms, bamboo and large lilies do well in the soft muddy soils and eternal wetness.  Only a few plants in here have mangrove relatives.  This part of PNG is perhaps too wet to provide an ideal nursery for mangroves as tolerance to drought stress is also an important mangrove characteristic.

Flood plain forest and creek
Inside the forest - most of the big trees have plank buttress roots
Secondary forest, which is where you want to be when the big trees fall.
Creek meanders often have bamboo, gingers and palms, plants that don't fall over in soft ground.
Even in the hills are signs of marine life
A creek in undisturbed, uninhabited rainforest on a hillside is completely brown with sediment and full of fallen trees
As far as I am aware, there has been no formal research into evolution of new mangroves in response to tectonic uplift.  Maybe this is something for you to research?
The coastal plains with grasslands, forests and tidal influence may not have been properly explored.

Tuesday, 25 November 2014

Creatures that Live in Logs in Mangrove Swamps

There is a small fish that lives inside worm holes in mangrove trees.  I first saw this fish 25 years ago on a university field trip and I remember the fish being called a cobra fish but googling that term finds nothing and I cannot find its name.  Finding names for mangrove log creatures seems to be harder than normal as not much is published.  The first step is to get a good photo of the creature, not easy when you have to open up muddy logs to find them and then try to get clean enough to use a camera.  What I discovered is that the fish are certainly not alone.  The biodiversity in rotting mangrove logs is as high as the biodiversity of a rock pool.

The mangrove forest where most of the photos were taken - Redden Island
Shipworm holes can be large enough to put your finger in and many are calcified
A small shipworm showing the shells that bore into the wood
The key species in the rotting log ecosystem is the ship worm. These worms, which are actually bivalve molluscs grind away wood using their shells.  Logs soon end up riddled with hole that provide habitat for a wide range of creatures.  Logs also have other habitats. Common mangrove crabs make tunnels under logs, not that they need logs, just that they prefer to tunnel under logs than burrow out in the open.  Another range of creatures live in the space that opens up under the bark when the bark becomes lose.  As logs can be different sizes, in different states of decay and in a different position relative to tide heights, each logs is different and no log supports all species.  In all at least 20 species of macro-invertebrate depend on mangrove logs in north Queensland. 

The photos that follow show some of the creatures that I found under or within logs.  Every tenth log has something interesting.

Parioglossus interruptus
These dartfish were under the bark of a tree that was completely exposed and had been so for possibly hours or days.  I assume the fish were in this position before I lifted the bark
The fish which are about 20 mm long can also be found inside the trees in shipworm holes.  This fish came out of a hole when I chipped into a shipworm infested log.
Non-descript crabs are the most common inhabitant
Giant flatworms up to 60 mm long glide through cracks
A giant flatworm coming out of a shipworm hole.  See the eye spots.
My new species for yesterday - looks like a species of stone crab
This snapping shrimp was as long as my hand and was found under a log
A colony of shrimps was present in the tunneled log shown above
I have very little idea what these 80 mm long creatures are

Wednesday, 5 November 2014

Constructing Machans Beach Seawall

Machans Beach which is a sandy island in the mangrove-infested Barron River delta is getting major seawall upgrade.  Category 5 cyclones have become regular events during the previous decade with at least 5 nearly landing at Machans (Ingrid, Larry, Monica, Yasi and Ita).  When you live here you can remember them well as you have pack up your bags each time and flee.  Machans Beach was lucky and was not directly hit but a place that is very similar in almost all respects was hit-Tully Heads.

The old seawall is very steep and many of the rocks are not supported from below
Graphic of seawall design from public notice sign -showing the lower angle and extended toe.
Like Machans Beach, Tully Heads did not have a properly engineered seawall.  The seawalls were constructed over time in response to local erosion events or storm damage.  Clearly these sorts of seawalls do not stand up to category 5 cyclones and at Tully Heads, nearly all the homes in the first 2 rows were lost. Seawalls can also be dangerous and kids playing on seawalls are sometimes killed by shifting stones and there have been local incidents.  Upgrading the Machans Beach seawall became a priority project.
Gap bashed though seawall by Cyclone Yasi - Tully Heads

Rocks thrown up from seawall onto lawns
To begin at the beginning, Machans Beach needs a seawall because the beach eroded.  The beach eroded because someone cleared the vegetation between the headwaters of two creeks and during a flood, one of the creeks, Thomatis Creek flowed backwards from the Barron River, over land and into the headwaters of the Richters Creek.   As a result of that flood in 1922 was that a channel was scoured between the two creeks and the Barron River developed a new path to the sea that was 7 km shorter than the old channel.  Much of the sand carried by the river followed the new path to the sea and Machans Beach lost much of its sand supply.  Adding to the issue, the old mouth of the Barron also shifted and the sand that was coming out was channeled out into deeper water.  Sand miners were also dredging very large amounts of sand out of the river channel.  It is an open question whether the mulit-million dollar seawall now under construction would have been needed if some controls had been placed on inappropriate land clearing 100 years ago and sand extraction from the bed of the Barron River was banned earlier.  A full description of the root causes of the beach erosion issue was written up in a Mulgrave Shire Council report, dated 1986.

Machans Beach Esplanade is very narrow, so another way had to be found to access the seawall
Construction of the seawall began at the northern end near Barr Creek at the beginning of May 2014.  A causeway was constructed about 15 m out from the existing seawall.  This method of construction avoided having to use the narrow esplanade and having to remove all the trees that were perched at the top of the old seawall. Seventy tonne trucks would reverse down the causeway and dump stone to the side of the wall so that a large excavator (30 tonne?) could individually pick them up and place them at the end of the causeway to extend the causeway. The size of the largest rock approaches the size of some of the smallest cars and it surprising that the excavator could handle them so easily.

Tipping out rocks
A larger rock barely fits in the bucket
Reversing along the wall to the excavator
Mirrors are handy for this job
By November 2014 the seawall stretched more than half way along the Esplanade and the causeway was in excess of 1 km long.  Trucks would drive forwards along the causeway and turn on little ramps that ran from the causeway to the Esplanade.  These ramps are also where the excavator is parked when the tide is high.  The trucks then reverse the final hundred metres or so the the waiting excavator.

The causeway is now so long, that the excavator has to wait for loads of stone to arrive
Before placing rock, mud is dredged from the tip of the causeway and placed on the side
A bucket full of mud - the mud was plastic so not much turbidity resulted
Dumping large rock with the excavator poised to catch the truck should it start to roll over
View along the top of the partially finished new seawall, showing soil being laid where the footpath will be
The seawall is made up in layers, which small stone (~150 mm) being formed into bank, which is then covered with a layer of geotextile.  Geotextile will add strength to the seawall as it has a very high tensile strength but its main purpose may be to stop fine material being eroded out of earth behind the wall by the movement of tides and waves.  Loss of fine material can create deep holes in the ground.  On top of the white geotextile is a layer of smaller rock, each of the smaller stones would be the size of the bucket on a builders wheelbarrow, which is roughly the size of the stone in parts of the original seawall.  On top of the smaller stone, truly large stones are being places with may having a long dimension of close to 3 metres.

Layered construction of seawall
The project will continue well into 2015 and I will keep you posted.

Tuesday, 4 November 2014

Fig Parrot Chicks

Of highest priority to saving the endangered southern race of fig parrot is finding a next with chicks so that a captive breeding program can be established.  If you live south of Rockhampton and you see parrots like the ones in this post, take photos if you can and contact the Department of Environment and Heritage Protection (email address is in recovery plan). Look for cheerful little faces looking at you from the trees.
Cyclopsitta diophthalma
My favourite fig parrot - this little chick watches what I get up to (1/11/2014)
Cyclopsitta diophthalma
I stand about 5 m away and take photos with a superzoom camera.
According the species recovery plan published in 2005, “Coxen's fig-parrot [the endangered subspecies] is thought to nest in the same manner as the red-browed fig-parrot [the subspecies shown in this post]. Training in north Queensland will be undertaken to hone the skills necessary for locating the nest holes of Coxen’s fig-parrot. This exercise will enhance observers’ abilities in nest recognition, particularly with respect to the height, aspect, positioning and appearance of nest holes, the tree species favoured for nesting and the preferred breeding habitats. In addition, familiarity will be increased with the appearance, flight style, behaviour and calls of the similar red-browed fig-parrot. The training exercise in north Queensland should be conducted by members of the recovery team in October or November so that the experience gained can be passed on to others and applied”.  Most of that information can be found in this post and previous posts on this subject.

Cyclopsitta diophthalma
A chick in a large dead paperbark in the mangroves about 15 m above the ground (5/11/2014)
fig parrot nest hollow
When I first saw the hole in September, a parrot was in it but taking photos with a smart phone through binoculars was not successful. When I went to take a photo a few days later, green ants were trying to claim the hole.  However the chick above survived the green ants  
In late September, I started to hear the noise of chicks begging for food.  Sometimes, I would even glimpse a bit of baldy head but the parent would enter the nesting hole and push the chick back if I observed too closely.  Now the chick or chicks are older, they are getting interested in the outside world and spend a lot of time with their heads out of the burrow looking around.  This may be the best time to look for active nests as you can make some funny sounds and the chicks come up for a look.  They are much less timid than the adults.  Fig parrots never become tame and do not make good pets.  With their really small tails they do not make good aviary birds as they can’t turn quickly and tend hit the end of the aviary as full speed, hurting themselves.  I would be careful about handling a bird that is not tame and that can chew through wood, not to mention that handling an endangered species would get you in serious trouble.

Cyclopsitta diophthalma
Dad to my favourite fig parrot chick
Most of the time, the fig parrots that visit my yard target green figs.  They eat some figs including Ficus racemosa and ignore other figs such as Ficus superba.  Ficus variegata is also a favourite.  They eat the seeds of the fruit and spit out the flesh and normally feed on green fruit, which would are dreadful tucker from a human perspective as they are full of sap-flavoured, glue-like resin.  Ficus racemosa fruit are very good to eat when fully ripe and have a flavour like strawberries.  I a pretty sure that Ficus variegata never really ripens and is never good to eat.  When the figs are the best for me, the fig parrots have long lost interest and think the idea that they normally feed on ripe fruit needs to be discarded.  Fig parrots tend to pick a cluster of figs and quietly chew for hours.  Cluster figs may be far more important that species of fig which have fruit dispersed through the canopy.  Normally, I detect the parrots by hearing the plugs of fruit the spit out landing on the leaf litter beneath the tree. When a few birds are present, the tree literally drips bits of fig.  The birds also make small squeaks as contact calls and the parent generally calls to be chick before approaching the nest hole.

Cyclopsitta diophthalma
Green Ficus racemosa is the best.  There are two birds in the photo.
Ficus racemosa
This is the first and only time I have seen a fig parrot on ripe figs.
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