Saturday, 20 May 2017

Spring Ptarmigan

The air has warmed up rapidly in Scotland over the first weeks of May and the winter snow is melting away. I have been on several hills during this time, studying ptarmigan Lagopus muta and although the cock birds can be quite vocal when displaying to and chasing neighbouring birds, when quiet, they can be very inconspicuous. There were six cocks in the area of the Cairngorms shown in the above photograph, all with a hen, one with two hens.

In spring, the cock and hen ptarmigan are coloured differently. The cock birds have grey backs and necks but retain their bright white winter feathers on their bellies. The hens moult into a mottled brown, yellow and russet colour. Both merge well into the rocky landscape and I only saw them because they were so active; the cocks disputing over territiry boundaries and guarding their hens from neghbouring cocks.

The hens' plumage merged extremely well with the dappled colouring of the heath plants; in this case mostly short wind-clipped heather. Soon they will rely on their colouring to hide on their nests in the heather which is too short to hide beneath.

The cocks' grey plumage blended well with the lichens that grow on the mounatin boulders. While the hens are incubating, they sit on nearby prominent look-out posts, usually a rock, so they too are perfectly coloured for their duty. And while the hens are incubating both sexes can be very inconspicuous indeed.

Tuesday, 25 April 2017

 Autumn walk - Bundanoon

It's autumn now in Canberra, a good time for bush-walking as it's not too warm. So last week I went for a walk in the Morton National Park, well a tiny bit of it by the village of Bundanoon. There are various short walks through the forest there, with lookouts over the depths of the Bundanoon Creek valley.

The route I took started down the Fairy Bower Access Trail, then along the Bundanoon Creek Walking Track, down to the creek in the floor of the valley, then straight back up Tooths Lookout Walking Track. I took a few hours and walked several km, but spent a lot of time looking around, exploring and taking photographs. And I walk quickly, so this is not a guide: for details of time and length of walks in the area please refer to the Bundanoon/Morton NP website here.

The stream that forms the Fairy Bower Falls slips slowly over the cliff.

Then cascade down in two vertical drops.

Tree roots stretch down the cliff looking for soil below, somewhere.

Orange lichens grow on the south-facing walls of sandstone - the shaded aspect.

Hand-cut and placed stone steps lead down the escarpment, winding through the trees.

Autumn is mushroom season and there were several varieties of fruiting bodies. However, I do not know the species, I merely admired their colours and forms. These white ones had wonderful veils around their caps.

These white ones shone like porcelain in the deep shadow of the tree trunks they were growing on.

This sky blue gem, I have tried to identify - Entoloma virescens ?

A giant staircase led back up to the plateau, through split rocks.

And up past another split rock - one cleaved by a tree that had seeded and grown in a crack in the sandstone. Over many many years, it has opened up the crack. Just how old is the tree I wonder?

Wednesday, 19 April 2017

How to avoid predators in a rock pool

I was snorkelling at Murrays Beach (Booderee National Park, Jervis Bay, New South Wales) last weekend and it was fabulous with warm clear water and a blue sky. The rocky shore dips into the bay creating ribs of reefs where a multitude of sea-life live. The highlights on this trip were cuttlefish hiding under ledges and huge schools of small fish of various shapes and colours.

But I don't bother taking photographs when snorkelling, I like to just watch the life go by. It was only when up top-side and walking along the shore afterwards that I took a few shots of life in the rock pools.

At first, things looked quiet and as though there were no animals living in the pools, until I saw a little movement in the green seaweed. A Sea Hare Aplysia dactylomela was slowly munching its way through the algae. It was only when it crossed a relatively open patch that I noticed it. If it had stayed in the thicker fronds, I would not have seen it.

So, I sat quietly and sure enough other creatures began to move.

A small shrimp twitched. The sea hare depended on coloured skin as camouflage in the weed, the shrimp had evolved a mostly transparent body for hiding from predators. That method allows it hide on any colour of substrate.

Then several shells began to walk across the bottom, but not with molluscs inside them, hermit crabs. They have adapted to use shells for protection.

And lastly, I noticed a school of small fish. As they were swimming up near the surface they should have been the first things to detect. Their bodies too, were quiet transparent and it was their shadows on the pool bottom that attracted my predator's eye. But, their schooling and safety in numbers appears to be their main defence tactic, which is fine as long as there are others in the school slower than oneself. There are twelve in the photograph, how many were there the next day, or the day after. There were White-faced Herons about.

Sunday, 19 February 2017

Reaching for sunflower seeds

A Crimson Rosella Platycercus elegans picks seeds from a sunflower outside a window

Sunflower seeds are a rich food and the garden birds love them. This sunflower grew wild in the garden, just outside a window. The seed had been in compost that was spread into the flower bed and then germinated. So we left it and it grew into a whopper. The plant is over two metres tall and the flower is about 40 cm wide.

The rosellas can pick the seeds out easily

The only birds that can gain the precious seeds are the Crimson Rosellas. The Sulphur-crested Cockatoos Cacatua galerita tried, but the plant could not bare their weight, nor the Australian Magpies Cracticus tibicen. So, the rosellas have them all to themselves. But now they have reached their limit, they cannot reach the seeds in the centre of the flowerhead. They can balance on the flower stem or the edge of the flowerhead and pull out the outer seeds, but they can't grab onto the tissue paper-thin seed cases in the flower to reach those in the middle.

It's just that they can't reach the seeds in the centre of the flower-head
They have clambered all around the flower and now look forlornly at the rich seeds still in the head. So, yes, I had to help them as I like them.

They have been stretching from all sides, gripping onto the edge of the flower
I have cut the flower head off and laid it out for them on a garden table. My good deed for the day done.

Saturday, 18 February 2017

A spectacular garden butterfly

Tailed Emperor Polyura sempronius

This magnificent butterfly was just outside our house yesterday, well it emerged yesterday, but as a caterpillar it had been in the garden for long before that. I never knew.

Hiding in the leaf litter at the side of the yard

I noticed it as it fluttered away from me when I was in the yard, and I could tell it had only recently emerged from its chrysalis as it was weak, only scuttling across the ground and into the leaf litter lying at the base of a wall. It looked so vulnerable as there are lots of birds in our garden and it would have been easy prey if any found it. So, as it was evening I took it inside for the night, lifting it by the feet, careful not to damage its scales. It was in lovely fresh condition.

In the evening I did a bit of research.

The splendid double tail on each of the hindwings - with lovely fresh margins and scales

After a good night's sleep I took it back into the yard and offered it a split grape or a chunk of pineapple for breakfast. It chose the pineapple, well these butterflies love their fructose. After a good long sip of juice it began to shiver to warm itself up. The sun was still hidden behind some trees.

Pineapple for breakfast

Then when the sunshine came through, I popped it onto the sunny side of the tree which it had been living on when a caterpillar, a Persian Silk Tree Albizia julibrissin. It immediately lined itself up so that its back was warmed by the sun through a thin gap between its closed wings. The previous night had been cold, so it took an hour or so of sunshine to warm up and begin to shuffle about. Every now and then, it shifted slightly to stay aligned with the sun.

Lined up to capture the sun's heat on its back

While I was waiting for the butterfly to take off safely, I kept close by, keeping potential predators away, and I had a bit of look through the branches of the Silk Tree. Sure enough, I found lots of nibbled leaves, and a recently emptied chrysalis.

Tailed Emperor habitat - the Silk Tree is above and left of the table

The chrysalis was like the tiny beginnings of a wasp nest, except that it was not paper, but keratin I suppose, and see-through as it was empty. I couldn't find any others, nor any caterpillars, but they hide in the leaf litter by day and climb up to feed on the leaves at night. I shall go out for a look after dark.

The chrysalis it emerged from, hanging empty from a small branchlet of the Silk Tree
- attached by a tiny silk button

Meanwhile, as the butterfly was keeping so still I took lots of photographs. I sent a set of shots to Suzi Bond, our local butterfly person and it was she who identified it as a female by her white abdomen and large size, with a wingspan of over 80 mm.

Her gorgeous face - her eyes had a black pearl effect, her proboscis was curled tight into her 'fur' and her labial palpi, a pair of  olfactory sensory organs, pointed up like a snooty nose

That was a very pleasant morning. I had learned a lot, and taken some curious shots of the butterfly, her face and wing pattern.

On recall, during the waiting, I had seen the leaves eaten in previous years, even found a spectacular green, horned caterpillar beneath the tree before, but I had not found time to identify it properly.

I left her to sun herself on her larval food tree, but once warm enough, she fluttered down to the ground and sat there motionless in the leaf litter. She obviously felt safer there where she was camouflaged.
I had found her in her favoured resting habitat.
 I'll watch the Silk Tree more thoroughly in future, and the ground below.