Beach Goodies

Well I said I'd share some of the other things I found at the beach, so I'd better do it! On this particular day there was quite a lot of seaweed washed up on the beach, so not surprisingly a lot of the things I found have to do with seaweeds.

The blue bottle, also known as Portugese man O'war is a blue coloured jelly fish with a nasty sting. Fortunately the ones I found looked pretty dead and only one showed any sign of still having tentacles. Interestingly is not a true jelly fish, but the 'jelly fish' is made up of many individuals of a colonial hydrozooid. In this photo the blue bottle has become entangled with a piece of Neptune's necklace.

Here are some goose barnacles that were living on the end of a piece of kelp that I found washed ashore. They are filter feeders that feed on plankton in the water column.














Sandhoppers are group of amphipods (little crustaceans) that feed on rotting seaweed that gets washed ashore. With their laterally flattened bodies and hopping movement they resemble large fleas, and are also known as sand fleas, but they are not true fleas.









Mussel's beard looks a bit like golden hair. It is a colonial hydroid, forming chains of tiny polyps (similar to corals) on mussel shells (front of photo).

Neptune's necklace (left of photo) is a seaweed endemic to New Zealand and parts of Australia. The little 'beads' are hollow and filled with water and gas, which causes the seaweed to float. They are also fun to pop and squirt each other with!

Sea lettuce is a bright green seaweed that when alive and healthy looks a bit like a leafy lettuce. The pieces I found though had washed ashore and didn't look very appetising (green bit in the middle of the photo).

Bladder kelp (right of photo) is New Zealand's largest seaweed and grow to 50m in length. It has air filled 'bladders' that help to keep the leaves upright in the water.

So there are plenty of things to find at the beach, or where ever you are, if you just stop and take the time to look :)

Ice at the Beach

The weather is warming up and it is beginning to feel like summer. So I went to the beach a few days ago, and went for a walk to see what interesting things I could find. I found that the ice plant was in bloom. So today I'm sharing with you some photos of ice plant and its flowers. I don't know why its called ice plant, its an odd name. 

Ice plant is a succulent that grows on coastal rocks, cliffs and sand dunes.

There are two species of ice plant in New Zealand - the native Disphyma australe and the introduced Carpobrotus edulis.

I think these photos are of C. edulis. C. edulis has leaves about 7 cm long while the native D. australe has leaves about 4 cm long.

C. edulis, also known as the Hottentot fig, was introduced to New Zealand (and other parts of the world) from South Africa.

The ice plant (both varieties) are edible. One can eat the fruits and the pickled leaves.

This is a flower bud, not a fruit! I didn't see any fruits.

The fruits are apparently (according to Andrew Crowe in his book "A field guide to native edible plants of New Zealand") quite salty, but the inner part is sweeter and more palatable, but has a rather slimey texture. 

The flowers come in yellow as well as pink

 Maybe I should give them a try sometime... 

The flowers seem popular with the bumble bees

C. edulis was planted on sand dunes in order to help stabilise them, but has since gone wild. According to www.biosecurity.govt.nz C. edulis is now considered an 'unwanted organism', because it displaces other sand dune plants and hybridises with the native ice plant species.   

It is a pity that C. edulis is becoming a pest, because it is such a pretty plant.

I'll share some of the other interesting things I found on my walk at the beach soon. 

Calendars :)

Thank you to those of you who offered suggestions for photos. I have now chosen 12 for the calendar and uploaded thumbnails below.

The calendars will be available for NZ$15 each + postage.

To order please contact me at amgrassham@hotmail.co.nz. I will need to know how many you would like and an address to post them to. I have set up a paypal account to accept payments. If you encounter any problems, please contact me and we can work something out.

Please allow a couple of weeks for printing.

If you have any questions, please don't hesitate to ask.

January

February

March

April

May

June

July

August

September

October

November

December

Exciting News!

I have some exciting news for you!

As I stated in my first post here, I want to share the beauty I see in the natural world with you. Many of you have been encouraging and supportive of my photography over the last few years, thank you! So I thought I'd give you a little heads up on a project I'm working on. I am proposing to get some 2013 calendars printed and I am wondering how much interest there is. I am currently in the process of selecting which images to use, but will upload thumbnails soon as I'm done.

I could use your help! Are there any particular photos (or sorts of photos) you'd like to see in the calendar? I'd love to hear your suggestions! I can't promise to use them, as there are some restrictions in terms of size and layout etc, but I will definitely consider them. I also have some ideas for future projects too - so if any suggestions are unsuitable for the calendar, perhaps they can be used in other ways instead :)

I will provide more details as soon as things are finalised. Feel free to leave any questions or comments. You may comment below, or email me at amgrassham@hotmail.co.nz.

Thank you!

Visual Field Map

It is school holiday time here in NZ, so I thought for something a little different I'd share with you a fun activity - one I enjoyed from biology class in my own school days. Equally, curious adults might enjoy participating just as much!

You may remember a couple of previous posts that talked a little about some of the amazing visual capabilities of creatures like the mantis shrimp. Well, today we are going to explore a little about our own vision and create our own map of our very own visual field.

You will need:

• an A3 piece of paper (or two A4 pieces with their long edges taped together, but only tape it on one side as you'll need to write on the paper)
• a selection of coloured pencils (or felt tip pens)
• a HB pencil 
• a ruler 
• a helper
• a piece of wall without pictures on it, furniture in front of it etc.
• blue tack, or some other means of affixing the paper to the wall
• a protractor (optional)

Instructions:

• Draw a dot in the centre of your piece of A3 paper with the HB pencil (if using two A4 pieces, make sure the dot is on the side without cellotape)

• Rule a bunch of lines radiating out to the edge of the paper from the centre dot. We made our lines at approximately 15 degree intervals, and I would suggest this as a minimum (it doesn't matter if they aren't exactly 15 degrees, so if you don't have a protractor its fine to just estimate). Lines that are closer together are fine, and will give a more accurate map of your visual field.

Your piece of paper should now look like this...

• Next attach the piece of paper to the wall, landscape orientation, so that when you stand against the wall, facing it, the tip of your nose is on the central dot. 

• Give your helper the coloured pencils, and looking straight ahead with your nose touching the central dot, ask them to pick one pencil and starting at the edge of the paper, slide the pencil along one of the lines (you should not know which colour pencil they have or which line it is coming down).

• As soon as you can see the pencil, tell your helper to stop, and make a mark on the paper where the end of the pencil is. Repeat until each line has been used. For this first part of the map, the same pencil may be used on all the lines if you wish. Once there is a mark for each line, use a ruler to join them together. This will map the edge of your peripheral vision. 

The map of your peripheral visual field should look something like this...

The human retina consists of two different types of photoreceptor cells - rods and cones. There are some 120 million rods in the human retina that detect changes in light intensity, shape and movement. Rods are distributed across the surface of the retina and it is these cells we use in our peripheral vision. Rods allow us to see in low light conditions but because they are not sensitive to colour, we have a hard time seeing colour in such situations. The same is true with the coloured pencil. Because it is detected first by the rods in our peripheral vision, we see it without knowing what colour it is...

• Repeat the exercise in the bullet point above, but this time make sure your helper mixes up which colour pencil is being used (Your helper may reuse a pencil if they need to, but make sure you don't know what colour they are about to use). This time don't mark where you can first see the pencil, but where you are first able to tell what colour it is. This will map your colour visual field. 

Your map should now look something like this...

The area of your colour visual field should be smaller than the area of your peripheral vision. This is because the second type of photoreceptor - the cones - are sensitive to colour, but they are concentrated near the centre of the retina, so the pencil has to pass further into your visual field before you are able to detect its colour. Each of the 6 million cone cells in your retina is sensitive to one of three pigments (unless you are colour blind, in which case one or more pigments is missing) - blue, green or red, and it is the combination of those pigments being stimulated within the eye that allows us to see the whole array of colours we see. They allow us to see the scene in front of us in detail, while the rods in our peripheral vision allow us to detect to if something is going on there, e.g. movement, so we can then turn our head to focus on what was there in more detail.

• Finally, don't forget to swap places with your helper so that they can have a turn! 

New Zealand Falcon

I have had the privilege of spending the last couple of weeks at my mother's farm. One evening while I was there, I was down the paddock winding down a little bonfire we'd had to clear away some old branches, when I saw what I at first thought was a harrier hawk fly up towards me from some bushes across the road, near the river. Harrier hawks are a relatively common sight at the farm, so I didn't think much of it, although I rarely see them that close – often I just see them soaring in high circles above the farmland. A split second later, I noticed it was carrying a small bird in its talons (sparrow sized, but otherwise unidentifiable in the poor light). It flew to the top of a nearby power pole, where over the course of the next 40 minutes I stood in awe as it consumed its prey. It looked stockier and smaller than a harrier should have been, standing atop the power pole, and I began to suspect I was observing a NZ falcon instead. A google search when I returned to the house confirmed that it was indeed the NZ falcon, Falco novaeseelandiae.  

The NZ falcon or karearea as it is also known, is New Zealand's only extant (non-extinct) endemic bird of prey. Our other native birds of prey such as the morepork and harrier hawk are also found naturally in Australia and some islands of the southwest Pacific. The NZ falcon actively hunts other birds, including those much larger than itself, such as the native pigeon (kereru). We've found piles of kereru feathers before, sometimes with a skeleton nearby, and thought it was probably the work of the falcon. I've heard stories of the falcon killing chickens and ducks too. They dive bomb their prey at speeds of over 100km/hr, not giving their prey much chance for escape or retaliation. They are also quite aggressive in defending their territory, especially during the nesting season, and will attack dogs and even people. A few years ago, when I was a volunteer doing rat trapping at a nearby national park, when working in an area where a group of falcon's had nests, I was advised to carry a stick of perhaps 5cm diameter so that the top of it stuck up a little above my head. Fortunately, they never tried to attack me, but the idea was that if one were to attack, it would swoop down and take out the stick rather than my scalp.  

I watched the falcon, on top of the power pole, as it preceded to pluck its prey, the downy black feathers floating off in the breeze like bits of ash from the bonfire we'd had that afternoon. After a time the flow of feathers trickled to a stop as the falcon began to eat its prey. It'd take a bite or two, then pause, lifting its head to look around, before returning for another mouthful. It held the carcass still with a foot, while plucking off the feathers that it discarded, and then the meat which it consumed. At one point it nearly lost the carcass as it slid off the edge of the cross bar on the power pole, but the falcon quickly grabbed it with its talons, and repositioned it back on the cross bar. It would have been interesting to have seen what would have happened had it not been able to catch the carcass before it fell to the ground. Would it have retrieved it, or abandoned it? Luckily for the falcon, it was not an issue that evening, and I will have to wait for another day to find the answer to that question. After a while, as it neared the end of its meal, I saw it regurgitate up some bits - apparently inedible bits that it had consumed. I knew the morepork does this, regurgitating up pellets of bones, fur, feathers and other inedible bits from the mice and other little creatures it hunts. I learned that the falcon commonly does this too after a meal. When it was done, it quietly flew off. 

I suppose some would find it was perhaps a bit of a gruesome scene to observe, yet to me it was highly fascinating and I felt incredibly lucky that I'd had the privilege of witnessing it. Although I have seen the NZ falcon once or twice before, it was both the first time that I had seen one at the farm and the first time I'd seen one with prey. The world is full of amazing creatures, and to me this was another example of that. 

Smiling in Yellow

Passing through the mall at lunchtime today, it was crowded as it so often is. But today was different from other days. Today was Daffodil Day, and perhaps it was nothing more than the cheerful yellow fabric daffodils pinned to most people's shirts, but the crowd seemed happier. Afterall, it is difficult not to smile at the crowd of bright yellow flowers and smiling faces, even when one is not ordinarily a fan of crowds. 

Outside, in people's gardens and city parks, clusters of living daffodils replace the replica's provided in the malls and shopping centres. Their heads bobbing with the breeze; their golden faces basking in the warm sunlight and smiling beneath a deep blue sky. They share with us their glad message that Winter has been left behind for another year and celebrate with us the arrival of the warmer days of Spring. Isn't it amazing that they (and other plants too) can tell just from slight increases in temperature and photoperiod (day length), imperceptible to us without measuring devices, that Spring is on her way, to sprout and be ready to bloom at her arrival? 

Members of the Amaryllis family, daffodils belong to the genus Narcissus. The exact number of species is debatable, ranging from 26 to 60+ depending on the species definition used. Part of this confusion is a result of hybridisation and breeding by garden enthusiasts/horticulturists. Daffodils are native to Europe, North Africa and West Asia, but are now grown around the world.

Not surprisingly, daffodils have a long history of cultural significance. In the mythology of ancient Greece, it is said Narcissus saw his reflection in a pool of water and became so entranced with it, he fell in and drowned (apparently other versions of the story say he was so transfixed that he starved to death) and from his remains the god's formed the daffodil, which sprang up at the site where he died. Perhaps this is where the genus name comes from.

The daffodil also features in ancient Chinese legends as a symbol of wealth and is associated with the New Year in the Chinese and Kurdish cultures. It is the national flower of Wales and also has associations with Easter in some Northern Hemisphere countries. 

How can one's eyes not smile at the sight? How can one's heart not rejoice in their company?

Signs of Spring

It is still almost a month until spring is officially here, but there are signs that she is quietly taking over from winter.

My mother reported the birth of the first baby goat of the year on her farm a couple of weeks ago, and it won't be long before it is joined by a few other kids and a whole lot of lambs.

Photo courtesy of Anne Grassham of Fleecewood Farm

But even here in the city, there are signs spring is slowly setting to work too. I was woken this morning by birdsong. The days are slowly getting warmer and the first of the spring flowers are beginning to appear. These are some photos I've taken in the past week or so...

(Does anyone know what this red flower is? It is a woody shrub that flowers late winter/early spring before the leaves come out. I've seen it around all my life, but don't actually know what it is... O_o)

And this afternoon I found some real evidence of spring - real daffodils (as opposed to the little mini varieties above that always flower earlier).

My New Room Mate

WARNING: This post contains graphic images of spiders. People with spider phobias may not wish to view the rest of this post.


Have you seen a spider with its prey, and been compelled to watch with fascination and intrigue, perhaps with a degree of disgust or a measure of fear thrown in? Or perhaps you've watched with curiosity, a spider weaving its delicate web and wondered how such a little creature could engineer such a beautiful death trap?

A couple of days ago, I noticed I had a little friend living by my window. He (or she) is much smaller than previous room mates I've had, such as this lovely fellow who kept me company a few years ago when I was in Nigeria: 

I was sitting on my bed, with my back leaning against the wall, reading a book one evening. This guy had been sitting quietly at the top of the wall, next to the ceiling, and I hadn't given much thought to his presence. All off a sudden I see movement out the corner of my eye, and turned to see him almost fly down the wall and stop, next to my head. Recovering from the surprise, I noticed he'd just caught a moth. I sat and watched him with fascination and a sense of awe, that I'd been privileged to be a witness to his hunt and subsequent feed.

While I do not know what sort of spider my Nigerian room mate was, my new little friend is a jumping spider. Jumping spiders belong to the family Salticideae, and are incrediably bright for being such little creatures with miniscule brains.

There are two major categories of spiders. There are sit and wait spiders. These are those that build webs to catch their prey, and they typically just sit out of sight near their web until some unsuspecting insect flies into it and gets caught up in the threads. Other spiders are active hunters. Both my Nigerian room mate and jumping spiders are active hunters. They still produce silk, which they might use as a saftely line (as with the jumping spiders) or to make their nests or egg sacs etc, but they do not construct webs to catch prey. Instead they are like the lions of the invertebrate world and actively stalk their prey.

As jumping spiders are active hunters, they have great vision with their eight eyes and spatial mapping abilities. Web building spiders have special tapping signals that the males tap out on the female's web, to tell her that he isn't prey but a potential mate. Some jumping spiders even mimic these tapping signals, pretending to be a potential mate, enticing the female out, where instead of finding a mate, she gets eaten! Spiders can be smart! They are incredible creatures. 

Anyway, I'd like you to meet my new little friend :)

Don't you wonder what those dark eyes are seeing and what is going on in his little brain? If you are in Christchurch, you might enjoy this seminar by Ximena Nelson, a scientist who studies jumping spiders.