Messing about in boats

Ratty, Moley and Badger (aka Joy, Cath and Andrew) went for a little kayak up Mangrove Creek, Chatsworth Island, last weekend.

Some eastern grey kangaroos watched patiently as we assembled our folding Feathercraft K-Light kayaks.

Alert but not alarmed - eastern greys, photo by Cath Clark

Mangrove Creek is an offshoot of one of the estuaries of the Clarence River. It was pretty muddy as we’d recently had a lot of rain.

Launching into the muddy river, photo by Cath Clark

The creek is lined with mangroves along much – but not all – of its length. Part of the bank is a nature reserve, and the opposite bank has the occasional house with solar power and generators. The agricultural area nearby is intensely sugar cane. We spotted some derelict cane barges rotting away. Many things used to be transported by river (cane, timber, supplies) before the land was opened up.

Andrew and Fog Fish inspect the derelict cane barges, photo by Cath Clark

In the best tradition of Wind in the Willows, we took with us a picnic, which Moley kindly carried in her hired expedition kayak as it had more space than either of ours. In retrospect we should have divided the food up and each carried some, as it added to her burden in the heavier plastic boat.

Joy and Murex looking for a picnic spot, photo by Cath Clark

The surprising thing was the lack of obvious wildlife – we saw some native waterlilies …

Native water lily, photo by Cath Clark

and an azure kingfisher (Alcedo azurea) fishing from a tree …

Azure kingfisher, photo by Andrea Arbogast, Wikimedia Commons

We usually see water dragons, cranes and even dolphins (and, heck, are dolphins big when you are on their level) around Ballina waterways.

On the plus side it didn’t rain, there were no jet skis (although some folks were running their generators) and only one (friendly) tinnie who was getting bogged in the shallow water, and the picnic was yummy.

Serene reflections induce serene thoughts, photo by Cath Clark

Sing with me the song from the Victoria Sings CD, if you know it:

The river is flowing,

Flowing and growing,

Down to the sea.

Mother, carry me, your child I will always be.

Water, water – life for a thirsty land.

The microbats are back!

Every year about this time (early autumn), a bunch of microbats decide to roost during the day in the ‘armpits’ of a terracotta bat I have hanging on my back deck.

Terracotta bat home for microbats

I don’t want to disturb them more than necessary, so just have a peak into the hole occasionally. I can’t tell what species they are without major disturbance, but they could be the east-coast freetail (Mormopterus norfolkensis). They eat insects at night and, according to A Field Guide to the Mammals of Australia, they roost in tree hollows and buildings. There seemed to be three this morning, but I’ve counted six huddled together in past years. The space is very small, and I hope they feel snug and protected. Weight is 7-10 grams each. They are truly sweet.

Before we put insect screens on the windows, we slept with the windows open at night and under a mosquito net (besides the nuisance value of whining mozzies, mosquito-borne Ross River fever and Barmah Forest virus are rampant in this area). Occasionally we’d be woken by the soft whirr of wings and the feeling that something was fluttering gently around the ceiling. Odds on it was one of these bats seeking food in the ‘cave’ of the bedroom.

Very little is known about microbats in this country. I copyedited an early edition of Churchill’s Australian Bats, and it was a joy to see photos of all those lovely little furry faces.

Moulting crabs

In a rock pool, you sometimes see what seems to be a dead crab but is really light and there’s nothing inside. If fact, the owner left behind its protective covering, which is what you see, and has gone elsewhere to live another day.

Shed exoskeleton of crab, Plagusia glabra

Unlike hermit crabs, which have a relatively soft outer coating (exoskeleton) and so need to live inside the hard shells of dead molluscs, the usual crabs you see have hard protective cases. This causes problems as the crab grows and feels more and more squished in its rigid case.

So what happens in detail is this. The short version is that the crab dissolves its hard shell as it forms a new soft shell underneath, recycling the components of the original shell. Its body absorbs water, swells and the old shell splits apart. It backs out of its old shell and the body continues swelling up so the new soft shell hardens around the bigger body. It had better be in a safe space over the several hours to days this takes place, or it is easy pickings. The yellow organs below are for oxygen exchange.

Inside the discarded shell

We saw three discarded shells of the same species of crab, and whether that was coincidence or an indication of seasonal moulting, I don’t know.

Final gloomy day creatures

Continuing from the previous two posts …

Carnivorous shells abound, but some herbivores are big and tough enough to survive – for instance, turbans. The turban below (left, Turbo militaris) is about the same size as its nemesis (right, Australian red triton, Charonia lampas)  and has a massively thick, protective shell. So does the triton.

Not exactly friends - the right would eat the left

And to show the actual sizes …

Big imperial turban (left) and big Australian red triton (right)

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More gloomy day creatures

Continuing from the previous post

It must have been a hermit crabs’ convention, as there were dozens and dozens. Perhaps they were there en masse to trade shells (they swap into larger shells as they grow) or mate, or just because there was a lot to eat. We saw close encounters, but perhaps that was because of the sheer numbers.

Hermit crab, Dardanus crassimanus

Hermit crab, Clibanarius viriscens, inside a Spengler's triton

Hermit crab, Dardanus crassimanus

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A gloomy day, full of life

Perhaps the heavily overcast conditions on Saturday fooled the critters at Flat Rock into thinking that it was dusk and wake-up time, but I have rarely seen so much life in the rock pools in one session.

For starters, we found five common Sydney octopuses (Octopus tetricus)! There were a couple in the same pool, but apart from each other. The white eyes are definitive of that species.

Common Sydney octopus

They all matched the colour and texture of the main seaweed in the pool, even becoming more or less ‘spiky’ as they moved fluidly across the bottom.

According to Norman and Reid’s A Guide to Squid, Cuttlefish and Octopuses of Australia, they can have an armspan of two metres, but these would have been only about one metre. This octopus ‘feeds on shellfish, which it drills and poisons, then pulls the shells open and eats the paralysed contents. This species primarily emerges at night to hunt crustaceans and gather shellfish. … Lairs can often be recognised by the bivalve shells scattered around their entrance’.

I’ve also seen the blue-lined octopus (Hapalochlaena fasciata) on this reef, but not yesterday. It was glowing blue at the time, so I left it well alone. I was slightly worried as their bites are reportedly painless, and inject a toxin that causes paralysis. If you can be kept breathing, you’ll be OK. Otherwise – not.

Another exciting find was more than 15 (I stopped counting) little ruby flatworms (Phrikoceros baibaiye). They are bright orange with small white spots and very active.  The edge of the mantle is very mobile. The head on the one below is on the left. We found one (or was it two?) appearing to chase its tail, going round and round in a swirl of skirts. Was it two mating, one laying eggs or just playing ouroboros?

Little ruby flatworm

Size of flatworm compared to Austrocochlea shell, photo by Andrew Roberts

While gazing at one flatworm, I became aware of a black nudibranch (Dendrodoris nigra) near it. Then I spotted a second black nudi nearby! You can just see the ‘naked gills’ at the back (top) of the nudi below.

Orange flatworm and black nudibranch

Another colourful inhabitant out feeding was the orange feather duster below. You can see the tube it withdraws into when it needs protection.

Orange feather duster worm

Here’s a sea urchin (Tripneustes gratilla?). It was camouflaging itself with seaweed so was barely visible in its pool.

Size comparison

When I put it back in the water, it put its feet out to move back to shelter (where I placed it in a more hidden spot after the photo).

Sidling away on a multitude of feet

Last (for this post – I’ll continue in another one as there was lots to see), I inadvertently startled a black sea cucumber, and it ejected its tubules of Cuvier in defense. These are quite sticky on the fingers. The animal regrows them.

Black sea cucumber ejecting tubules of Cuvier as a defense

Catfish skull

Here’s a catfish skull I found on the beach at Flat Rock, Ballina – I’m not sure which species exactly as we have several, both marine and freshwater, in Australia.

Catfish skull, top

Catfish skull, underneath

It’s 12.5 cm (5 inches) long and 4.5 cm (about 2 inches) wide. An unusual find on the beach.

Getting quieter at night

Now summer is over, the frogs have calmed down. They were really loud this year – so loud that my ears were buzzing some nights as I lay in bed (I have a small pond outside my bedroom window). The cicadas were causing that effect during the day, so it’s a wonder I have any hearing left.

But frogs are still around, if silently. A couple of bleating tree frogs (Litoria dentata) insist on sheltering within my rain gauge. Occasionally they get in the actual water, which makes for somewhat inaccurate readings. But most of the time they are in the outer part of the cylinder. I tipped this one out to get a good look at it – it’s only about 2.5 cm (1 inch) long.

Bleating tree frog

Bleating tree frogs have a prolonged call that sounds a bit like a bleat, but nowhere near the ‘baaa’ of the bleating frog I heard in an urban wetland in Decatur, Georgia (USA). That really did sound like a sheep! It was probably the US eastern narrowmouth frog (Gastrophryne carolinensis).

The green tree frogs (Littoria caerulea) that live somewhere in the bathroom and crawl out at dusk have also disappeared. In summer, up to five of them creep slowly across the room towards the glass louvres and outside to hunt. They all freeze when I put the bathroom light on. It’d be a bit horror movie if I didn’t like them so much. Each of them is bigger than my fist. They’ll be back next summer.

Green tree frog crawling out the bathroom window to hunt at night

Luckily there’s a fairly easy way of identifying frogs in summer – by their calls. Each species has a unique call (the males do the croaking), and David Stewart has done the hard yards of recording the calls and producing a CD. That way you don’t have to crawl around in the pitchy black trying to find them under reeds and stones.

Thanks to David, I’ve identified the brown-striped frog (Limnodynastes peronii) …

Brown-striped frog, photo by Jean-Marc Hero, Wikimedia Commons

Cogger’s Reptiles and Amphibians of Australia describes the male’s call as ‘a single loud “plonk” or “toc”, like a hammer striking and anvil, repeated at intervals of a few seconds’, and I’d agree with ‘toc’. (In bird ID books, I often can’t grasp the description of the bird call and when I heard the actual bird, it’s nothing like the description.) It is ‘a highly successful urban species [in addition to being associated with slow-moving streams, marshes, dams and ponds] which thrives even in small, decorative garden ponds – exactly what I have outside my bedroom, as well as having a slow-moving stream and small dam on the property.

I have also heard the great barred frog (Mixophyes fascilatus) – call a ‘deep, harsh “wark”‘ – living in rainforests, antarctic beech or wet sclerophyll forests (the property has rainforest gullies) …

Great barred frog

Great barred frog, photo by LiquidGhoul, Wikimedia Commons

and the rocket frog (Littoria nasuta) – a very fast, ‘wik, wik, wik’ call -…

Rocket frog, photo by Poleta33, Wikimedia Commons

I didn’t have to crawl around in mosquito-infested swamps to find this one, but it’s not an Australian frog …

Froggus metallicus, South Carolina Aquarium, Charleston, Georgia, USA

or these …

Froggie band, South Carolina Aquarium

I’d love to have these in my garden – the kookaburras and butcherbirds could perch on them. And they wouldn’t be noisy at night.

Pardalotes on the move

This morning Andrew spotted a striated pardalote (Pardalotus striatus) on the insect-screen of the door to the studio. It flitted away so fast there was no time for a photo, so I’ve used someone else’s.

Striated pardalote, photo Ric Raftis, Wikimedia Commons

They are little birds, smaller than house sparrows. Simpson and Day’s Field Guide to the Birds of Australia calls them ‘acrobatic foragers’ and that’s pretty accurate. We saw them yesterday when we were out clearing the fences of summer weeds – flitting on ‘fast forward’ in the tops of the tall gum trees, chasing insects.

We’ve also seen spotted pardalotes (Pardalotus punctatus), in almost exactly the same environment as the one below. This is a female at her burrow – a hole dug in the side of a clay bank.

Spotted pardalote female with burrow, photo by Esther an, Wikimedia Commons

Pardalotes occur all over Australia, except in the very dry areas. I once found one, dead as a doornail, on the footpath in Sydney as I was walking into the city for a haircut. I put it in a tissue in my handbag and didn’t mention it to the hairdresser. I was able to get a close look at it at home.

A few bugs in the system

I enjoy seeing unusual bugs and beetles (one of the differences is that bugs have sucking mouthparts and beetles have chewing mouthparts).

Here’s a beetle that landed on my manuscript this morning. It looks like a ladybird. What a striking pattern! The delicate feet and antennae! Entomology is such an enormous field, and I’m woefully ignorant about insects’ scientific names.

Ladybird beetle

This next one is a really pretty beetle (the chewing mouthparts are visible on the photo), found in my garden. The colours! The texture! The three-pronged antennae!

Shiny beetle

Andrew took this one of a giant water bug (Lethocerus insulanis). The colour is dull but the geometric pattern is intriguing.

Giant water bug, photo by Andrew Roberts

For enthusiasm combined with meticulous observation, I recommend Fabre’s The Insect World Of J. Henri Fabre, translated by Alexander Teixeira de Mattos. Fabre wrote many works on insects from his own observations, and the language has a wonderful and joyous style – Fabre obviously loved his insects. Electronic text versions are available.

Like that quote about art, I don’t know much about insects, but I know what I like. They often seem like works of art in themselves.