Archive | December, 2013

On the Edge of the Blue Line

25 Dec

On the Edge of the Blue Line

The sand is golden with a uniform, rippled pattern to it; like the sole of an old fashioned sneaker. Every few metres small clumps of grassy weed appear until finally the sand merges into an endless green meadow of seagrass. Seagrasses are not algae but true plants with leaves, roots and in most species, flowers. They form a crucial ecosystem in the shallow waters of Gulf St Vincent. As I hover above the dense mass of leaves, a school of tiny silver fish lifts out of their embrace, swims a few metres then blends back into the shelter of the meadow.

1

Blue line as seen from the sand hills near Henley Beach

 

I am snorkelling off Henley which is better known as a fashionable beachside cafe strip rather than a dive destination. I decided to arrive a little early and enjoy a cup of coffee while I waited for the sun to get high enough for underwater photography. The water is clear and the ocean warm and inviting at this time of year and it is just a short swim from the local jetty to the blue line where the sand and seagrasses merge. The lush tangle of gently waving blades that surround me are home to one of the planet’s richest marine environments. It is a place where whiting, mullet, blue crabs, giant rays and squid (to mention just a few inhabitants) find food and shelter for themselves and their young.

2 Seagrass meadows

Seagrass meadow

 

I swim a little further into the seagrass until I locate a patch of sand with some darker detritus around its edge, indicating that something might have dug into the substrate. I stir the sand with the tip of my dive knife…nothing…I swim a few metres further and repeat the process. On the third attempt I get a result. A dinner plate sized blue swimmer crab bursts out of the sand with pincers extended and full of aggression. These crabs are prolific along the upper gulf in the summer months providing a valuable commercial fishery and great sport for recreational fishers and divers.

5 Blue swimmer crab

Blue swimmer crab

 

Experience has taught me that the boundary between seagrass and sand is an ideal place to observe different animals. Because I am wearing extra weights I am able to rest effortlessly on the bottom in this zone and wait for something to happen. Over the next few dives my strategy pays off as a small group of juvenile King George whiting settle close to me as they search for worms and molluscs between weed and sand.

4 Juvenile King George whiting

Juvenile King George whiting

 

A little further offshore small sand patches occur regularly in the seagrass meadow. Often there are a few rocks colonised by brown or green algae and even variations in seagrass species in these areas and these slight variations in terrain frequently produce the greatest diversity of marine life. My first sand patch does just that. Lying close to the bottom, I let my eyes adjust to the light and moving shadows produced by the tidal flow and rippling surface. Just a few centimetres from my lens a seahorse clings to a blade of eelgrass using its tail and tiny fins to move in time with the swaying miniature forest of the underwater meadow.

3 Big bellied seahorse

Big bellied seahorse

 

I have been in the water for over an hour and I am getting a little chilly and besides a cappuccino and breakfast roll beckon back at the Henley Square where many a tourist sips coffee unaware of the glorious marine world just a short swim away.

 

Cheers

Baz

 

 

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Willunga’s Blue Bees

13 Dec

 

Dear Reader:

A few weeks ago I spent a weekend in the charming little country town of Willunga just south of Adelaide, in the McLaren Vale wine region. I was updating some illustrations in one of my wildlife books and needed some photographs of honeyeaters feeding on different coloured flowers. We stayed in a heritage B&B on the edge of the town with a lovely garden featuring stands of agapanthus, native hibiscus and several large bottle brush trees. Throughout the day a variety of birds, including both new Holland and white plumed honeyeaters, used their elongated beaks to probe the blossoms and hawk for insects.

1 Willunga has many fine old colonial buildings

Willunga has many fine old colonial buildings

 

As well as honeyeaters the plants attracted more than their fair share of bees. Between sips of wine and a nibble of cheese (doing it tough that day) I watched them flit from one blossom to another gathering nectar and collecting a dusting of pollen on their legs. Then, out of the corner of my eye, I caught sight of one bee flying more erratically than the others, it seemed to hover for a second then repeatedly zoom off in different directions; like a miniscule attack helicopter. Every so often it would land but only for a short time before resuming its unpredictable flight pattern.

2 New Holland honeyeater probing bottle brush flowers for nectar

New Holland honeyeater probing bottle brush flowers for nectar

 

I moved my chair a little closer to the native hibiscus, where the little insect seemed to be spending most of its time, set the camera to macro zoom and started to track it through the lens. The bee was certainly smaller than the honeybees that were also doing the rounds of the blossoms and it appeared to have a bluish tinge. I fired off a couple of frames and took a closer look on the review screen. It was certainly not a honeybee. Over the next hour and a half several of the little blue bees appeared at different times and I managed to get a series of images that I could use to identify them. I suspected they were native bees which I had heard of but knew very little about.

3 Honeybee feeding on a blue agapanthus

Honeybee feeding on a blue agapanthus

 

My guess was correct. The little insect was a blue banded bee (Amegilla cingulata). Blue banded bees are actually far more common than I realised and are found throughout SE Asia. They contribute to the pollination of many commercial crops with their unique ability to buzz pollinate; the result of intense wing vibrations when they cling to flowers.

4 Banded blue bee hovering in front of native hibiscus 2

Blue banded bee hovering in front of native hibiscus blossom

 

Unlike honey bees these native bees are not colonial with females building burrows in dried up river banks or even soft mortar in urban housing. Their sting is mild and they are not aggressive. Interestingly, these blue bees collect most of their nectar from blue flowers and since my initial sighting I have found them on the lavender and agapanthus in my own garden. They have obviously been there for years and I had never even noticed; yet another lesson in observation.

Cheers

Baz

 

 

 

Birds with Attitude

3 Dec


Dear Reader:

There were magpies scattered through the little park. I had seen them high in the trees and foraging nervously amongst the undergrowth. Every time I came close to one it would fly off and perch on a branch and watch me suspiciously. Suddenly, a small group of what I surmised must be sub-adults because of their grey flecked backs, decided to congregate in the understory just a few metres away from where I was sitting. They warbled and strutted and then seemed to organise themselves into a group.

E Magpie with attitude

The magpie strut

 

The birds moved in a skirmish line through the leaf litter chasing butterflies and raking through the ground with their powerful beaks. Every so often one would lift up its head and gulp down a grub then return to the hunt. I was perched on a fallen tree branch, clearly in their way but the birds just kept coming closer, brimming with the confidence that youth and inexperience bestows on many species including our own.

D Magpie with grub

Magpie about to swallow grub

 

Australian magpies (Gymnorina tibicen) are actually a member of the butcherbird family. They are medium sized, robust birds growing to around 44 cms in length with powerful stabbing beaks that are used for digging out ground based prey and for defence. Magpies live in groups of 2-24 birds with distinct social stratification- several high status females usually breed with a dominant male and the remainder live on the periphery helping to protect nests. They are extremely territorial during the breeding season and many a cyclist, golfer or innocent pedestrian crossing the parklands will tell tales of being attacked by dive bombing magpies.

F Magpie cleaning beak

Magpie cleaning beak while foraging

 

My far less adventurous magpie moment occurred inside a little conservation park in Burnside, one of Adelaide’s more affluent eastern suburbs quite close to the hills face. The park is classic scrub reminiscent of the way the plains would have been before European settlement. Tall eucalypts and native pines dominate the upper story and a variety of low bushes including spiky acacias form the mid range vegetation. Being the end of spring, there were still quite a few flowering plants amongst the leaf litter and fallen branches. And when I sat quietly and watched intently it was possible to catch glimpses of tiny brown skinks searching for prey in the jumbled layer of leaves and bark.

C Adelaide rosellas

Adelaide rosellas on the track near the park entrance

 

However, magpies were not the only birds using the park. As I entered through a side gate I watched a pair of Adelaide rosellas nibbling grass seeds on the path a mere 20 metres away. And the usual suspects; noisy miners, new Holland honeyeaters and some tiny, twittering finches, all added to the sounds and sights of my walk in the park.

B Meadow argus butterflies

Meadow argus butterflies

 

Cheers

Baz

 

 

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