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.

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.

Something eats Fiddler Crabs

Just when I was beginning to believe that fiddler crabs were so good at avoiding predators that predators didn't bother with them, I find evidence of predation.  In a 30 m section of creek bank, I found 3 broken off fiddler crab claws and a partially eaten body.

As I had observed that same creek bank at 9 am, I knew that the predation had occurred during the day as it was 3 pm when I observed the claws.  At night the forests are stalked by the Australian water rat (Hydromys chrysogaster), which is a voracious predator of crustaceans and is like a tiny otter rather than a rat.  Their footprints can often be seen in the mud and on the beach.  So what preys on crabs in the middle of the day.  It was not people – no fresh footprints and people did crabs up which makes a mess.  In fact their were no footprints which made me thing that the predator was a bird.  Birds can carry their victims away from the site of capture before processing their prey and swallowing it.  In this case the large claw was removed.

Without footprints the only way to check out suspects was to photograph birds and look for mud on their beaks.  In the patch of mangrove forest where the crabs were taken were kookaburras, black butcher birds and scrub fowl.  On the sand flats next to the mangroves were several more candidates including a beach stone-curlew and various herons.

Beach stone-curlew, white-faced heron and great heron

My bet is that it was the kookaburra that took the crabs.  Scrub fowl scratch for their prey and generally are not present in the mangrove except when they are moving between islands of beach scrub within the mangroves.  Butcher birds generally attack prey by gliding in with a dead straight trajectory so that their approach creates very little apparent movement in the eyes of the prey.  However crabs are fast and they run when other crabs run and the other crabs with different angles of view would seen the butcher bird move.  Herons seem to be interested in fish not crabs.  The beach stone curlew had mud on its beak, but this species is very shy and is a creature of open spaces.  I doubt that it would go into the mangrove to catch crabs.  That leaves the kookaburra.  Kookaburras often sit on a lawn waiting for something to move so I suppose they could do this in the mangroves.  The photo seems to show mud on the kookaburras beak, however they wipe their beaks on branches to clean them so there is only what looks like a film of dry mud on their upper beak.

Beach stone-curlew - Esacus magnirostris

Kookaburra with mud on its beak a few metres from the crab remains

Mud Crab Food

At the mouth of the Richters Creek (Cairns), shells are balanced on the mangrove prop roots.  What is this all about?

Mud-creeper shells in a tree

Many of the shells are severely damaged and this is a clue.  There is only one animal that can follow the spiral, crushing away solid shell - the mud crab.

Mud crab damaged Telescopium shell

Hermit crabs appear to be the main prey although according to the scientific literature mud crabs can prey on the Telescopium and Terebralia mud-creeper snails as well.  After the mud crab has eaten the shell's current inhabitant, an new inhabitant often moves in.  A full sized shell may be reduced in stages down to small remnant as inhabitant after inhabitant is eaten.  It is no wonder hermit crabs have learned to climb trees.

A hermit crab

The Nemertean

Mangrove swamps at night are totally quiet with all life seaming asleep except for the nemertean.  These curious predators which are from 10 to 25 cm long hide in cavities in fallen logs during the day.  At night they move slowly across the mangrove floor in search of prey which they catch with an eversible proboscis.  This curious organ can be thrust forwards nearly as far as the animal is long.  At the end of the proboscis is a poison stylus or a sticky pad, for this species, I do not know which.

A mangrove ribbon worm - Pantinonemertes sp.

Below, a video of the eversible proboscic.