Backyard Jewels

Golden buprestids

Golden buprestids from the collection of the Royal British Columbia Muesum

In my opinion, nature’s best visual trick is iridescence, which can transform an ordinary beetle into something extraordinary. The dried up beetle carcasses above are one of the prettiest examples of iridescence I’ve ever seen up close. The beetle is a golden buprestid (Buprestis aurulenta) which lives in my biome. As larvae they spend two to four years mining through recently dead conifer trees, whether that tree is rotting on a forest floor or part of your new coffee table, earning themselves the title of ‘pest’.

Ellen Terry as Lady Macbeth 1889 John Singer Sargent 1856-1925 Presented by Sir Joseph Duveen 1906 

Once they morph beyond the furniture-eating stage, their exoskeleton matures to an iridescent green with brass coloured fringes around the wings. Strung together, these beetles would make a necklace suitable for a fancy ball, and I’m not the first to consider an iridescent beetle fit for a resplendent occasion. Ellen Terry, perhaps the most famous actress in the Victorian era, wore a green dress decorated with iridescent beetle wings to play Lady MacBeth in 1888. The dress must have looked stunning under the stage lights (here are some pictures).

But, beetles don’t hold a monopoly on iridescence; in fact, a diverse group of animals have independently evolved with their own version of colours with variable intensity and hue depending on the angle they are viewed. Examples abound in my own yard from dragonflies, butterflies to hummingbirds and more.

 

 

 

Why be iridescent?

An obvious use of iridescence is to communicate. A flash of bright colour might scare a predator away or say “I’m poisonous, so don’t eat me”. Or an animal could produce a flashy show to attract a mate (these guys put on the best show – but unfortunately don’t live in my yard). An untested hypothesis is that iridescence may help a school of fish or a flock of birds organize themselves – another form of communication. For example, the iridescent patch on a mallard duck’s wing may be a cue to help them fly in the same direction.

A flock of mallard ducks (they thought I had food)

Counterintuitively, iridescent colours can also be used to hide, which explains why little fish like herring and sardines are so shiny – when looked at from below, their shininess blends with the shininess of the ocean surface. Or an animal can use iridescence to pretend to be something else – what looks like a drop of dew on a leaf might actually be a green leaf beetle (golden buprestids are probably too big to do this).

Interestingly, some instances of iridescence evolved before the organisms bearing iridescent structures developed the ability to see. One theory as to why iridescence evolved is that the structures that can create iridescence also create strength – so perhaps the iridescence of the golden buprestid is a side-effect of building a strong exoskeleton. We know these exoskeletons last, as fossilized beetles as old as 49 million years have been found that are still iridescent (Parker and Mckenzie, 2003).

T

The above golden buprestids was found by my better half in our backyard. Since I have one in my collection, I only need to find about a thousand more to make a ballgown of my own.

References

(1) Doucet, M. and M.G. Meadows. 2009. Iridescence: a functional perspective. 

(2) Parker, A.R, and McKenzie, D.R. 2003. The cause of 50 million-year-old colourProc. R. Soc. B270S151S153. 

I originally posted this article in January 2015 – find it here.

Blue Feathers – almost coherent scattering

A collection of Mountain Bluebirds at the local museum

This year, Stellar’s Jays have been common in my neighbourhood, it’s the only wild blue bird we get here. But, it has a secret, it’s feathers are pigmented to be black. They look blue because of an optical trick that occurs within the feather’s structure. And Stellar’s jays aren’t the only one using this trick, all the birds out there with blue feathers are doing the same thing.

In the late 1800s, naturalists used the recently discovered concept of Rayleigh scattering to explain why blue feathers were blue. Since tools to examine the nanostructure (structure in the order of a billionth of a meter) of a feather hadn’t been invented yet, naturalists assumed that a feather contained tiny transparent cells full of particles the right size to create Rayleigh scattering. Like the sky, blue light would be more efficiently scattered. As a result, to our eyes these feathers would appear blue.

Because Rayleigh scattering is incoherent, it produces the exact same colour irregardless of the observation direction. Since blue feathers in natural light don’t change colour depending on viewing direction, the assumption that their colour was formed through Rayleigh scattering seemed valid — until someone looked closer.

In the 1930’s, scientists examined a a non-iridescent blue feather under a directional light source. Colour variations were observed as the light source was moved – an iridescent characteristic that called into question the hypothesis of Rayleigh scattering making the feather blue.

By the 1940’s, a cool new gadget became available – the electron microscope. Now the internal nanostructure of blue feathers could be directly examined. On the first look, the internal feather structure appeared to contain randomly spaced objects. This meant scattered light would be incoherent resurrecting the hypothesis of Rayleigh scattering being responsible.

It took until the 1970’s for scientists to finally determined that the nanostructures were, in fact, not fully random. Instead they were a quasi-ordered matrix – not quite the perfect order of iridescence but not the full randomness required for Rayleigh scattering. Under natural light from all directions, like sunlight, these feathers appear to be the same colour from all directions. However when a directional light is shone on blue feathers the colour will change depending on the light direction.

A Blue Jay wing (I don’t have a close up of a Steller’s Jay)

Since the colour of a Steller’s Jay’s feather comes from its internal structure on a tiny scale, a damaged feather would lose its blue colour. The dark pigments in the feather, that act to help show off the blue, would make a damaged feather would look almost black. So if you are lucky enough to find a Steller’s Jay feather, take care of it to keep it blue

wildlife in the food forest

P1100476

The visiting Cooper’s hawk – check out his jewelry.

Converting the monoculture of my front lawn into a more diverse ecosystem was one of my goals when we started building a food forest last year. For wildlife we took a ‘build it and they will come’ philosophy that has worked. Bees and ladybugs quickly moved in as soon as there were flowers, and spiders have spun their webs everywhere. Little birds now hunt for food among the trees and plants – juncos, golden crown sparrows, and fox sparrows find meals on the ground while the Anna’s hummingbird that calls our yard home frequents the flowers, especially the currently blooming broccoli.

A couple of days ago I spotted something new – a Cooper’s hawk was perched on the top bar of our not-deer-proof fortification intently watching the old laurel bush by our deck. The laurel bush is covered with berries I suspect are toxic but the neighbourhood robins had taken to feasting on them (based on the droppings on the deck, the berries appear to disagreeing with the robins digestive systems). Hundreds of robins were flocking to the bush and capturing the hawk’s attention. Cooper’s hawks regularly eat robins and this one had figured out a trick.

Every now and then some robins would spook and fly off. The dumb ones flew low into the fortification netting. Bird panic ensued as they discovered their path was blocked, as the robins frantically looked for a way out the hawk would swoop in. I didn’t see him catch his dinner, but I’m sure in time his method would be successful.

IMG_0897

My visiting hawk is the one on the far left (photo by Andy Stewart)

I took a couple pictures of the small raptor since he was distracted enough to let me get close. When I showed the pictures to my husband we noticed the bird was banded and we could clearly make out the number on his band. My husband used his contacts to find out a little about the bird and to report that we saw him. It turns out this hawk was born in town sometime in the spring of 2010 and banded shortly thereafter – I was even sent a baby picture. He looks like a healthy urban hawk to me and I’d be happy to see him again in the yard.

P1100372

A representation of deer congregating to eat my food – I don’t have any actual pictures because when I see them I’m busy chasing them away.

Other, more problematic wildlife I wish wouldn’t visit. My food forest has been slow to develop mostly due to wily deer that keep finding ways inside our not-deer-proof fortification. Since I irrigated all summer, inside the fortification was lush and green compared to the parched lawns on the outside. Clearly, I created a tasty destination for our urban deer. We’ll be rebuilding the fence over winter to prevent (hopefully) the problem next summer. The pole beans and broccoli took the brunt of the deer damage, but my apple and cherry tree were also munched on – hopefully they recover next spring! As an aside both the ground cherries and Irish poet tassel flowers were entirely ignored.

Introducing Licorice and Stout

P1100030

Licorice the hen

My Sunday morning began with a trip to collect two new hens. I went with pullets (hens who are old enough to start laying eggs) this time. As cute as chicks are, they are messy and take a lot of work. My husband is clearly longing for fall beers since he suggested Licorice and Stout as names. They’re just an industrial cross, not a quaint heritage type.

Right now, the two new hens are relaxing in an un-used rabbit hutch, tonight they’ll go in with the flock (Butter, Kung-pow, Salt and Pepper). Hopefully, in the morning the hens will all wake up and assume the two new ones were always there.

P1100029

Stout, the other hen

Waking to a martian sky

P1080926

Guilty of causing a ruckus

I was rudely woken by a chicken kerfuffle this morning. The hens were going on as though Stumpy our resident raccoon (he’s missing his tail) was inside the coop. Sadly it was just after 5am. I stuck my head out the window, not a racoon to be seen and the chickens were showing no sign of abating the ruckus. I’d prefer not to annoy my neighbours, so I went outside and tossed some chicken chow in the run to distract them. It worked, the hens quieted down so I went back to bed.

I closed my eyes and relaxed – moments later the cacophony resumed banishing any hope of further sleep. Grumbling under my breath, I went back outside to see what I could do to shut chickens up.

As I got near the coop a Cooper’s hawk emerged from the cedar hedge. The raptor took flight, barely generating enough lift to miss the raspberries. The hawk must have roosted only a metre or so from the hens – and had been closer than that to me when my sleepy self tossed in the chicken food and I didn’t notice. Clearly the hens noticed the predator lurking near by.

As soon as the hawk was gone all the resident little birds, Bewick’s wrens, chipping sparrows and such, burst into song. Thankfully, the hens fell silent and got busy eating the extra food. I didn’t intend to be out in the garden that early, but it felt magical as though I’d been transplanted to a different planet.

For the last few days our sky had been blanketed with a yellowish haze – high level smoke from near by forest fires (not a Russian conspiracy of dumped toxic gas from the cold war that a random stranger I encountered on a hiking trail insisted). The weather man on the radio forecasted that winds will take the smoke away over the next few days. But for now it looks like we are under a martian sky.

While on my early morning garden tour, I looked straight at the just risen sun (yes I know I shouldn’t do that). The sun was deep red and muted enough it didn’t hurt my eyes to look at it. Pretty neat to see, assuming we’ll be back to our normal summer blue sky soon.

Hummingbird vs Crow

IMG_1849

An Anna’s Hummingbird sitting on her nest

Yesterday, I watched a hummingbird charge at a crow.

The crow strayed to far across her unmarked boundary line. She burst out of the holly bush like a bullet straight for the much larger bird. With a startled ‘caw’ (I tend to anthropomorphize animals in the yard) the crow jumped out of the way and flew to the top of the fir tree on the other side of our fence. Taking a page from a WWII dive bombing manual, the hummingbird made repeated passes at the crow, getting closer and closer. It wasn’t long before the crow had enough and flew away.

The little aggressive female Anna’s Hummingbird has lived, year round, in our yard since we moved in and it wasn’t the first time I’ve seen her chase off a crow. The yard is her territory and she actively defends it (I’ve seen other hummingbirds behave the same way around feeders).

P1070816

My rather mutant looking bee balm just starting to bloom

Our yard is probably worth defending. I’ve planted an assortment of hummingbird friendly flowers, like bee balm, that provide nectar from early spring to fall. In winter we see her picking through the cedar hedge hunting small insects. Every summer we spot a few juvenile hummingbirds hanging out in the yard, so our Anna’s Hummingbird is very successful.

Hummingbird photo by G. Hanke

some eggy tidbits

IMG_0137

Both of these chicks turned out to be hens.

The longer days have resulted in a glut of eggs around here – hens I had thought were well into henopause have started laying again, and a chick I got last year that left me wondering if it was a rooster has proven she is a hen (I’d happily keep a rooster, except that in my urban area that wouldn’t be fair to my neighbours). With extra eggs in the fridge, I’ve been thinking a lot about eggs.

Ever dropped an egg? It turns out an egg can be repaired – good news for Humpty Dumpty! Even better news for a Kakapo egg as these ground dwelling parrots are critically endangered. Here‘s a story about an accidentally crushed Kakapo egg that was repaired, then hatched.

Or, considering Easter is approaching, how about natural egg dying? These natural, homemade dyes look great – especially the blues and reds. Beet juice creates a great red/purple/pink range of colours. Perhaps not really appropriate for dyeing eggs, crushed cochineal insects also produce a great and non-toxic red dye that is found in all sorts of processed food. As a slight tangent – up until roughly the 1950s, cochineal was the dye used for British army uniforms. This dye gets listed under a number of different names such as ‘natural red 4’ or ‘red #40.’

In general red colouring in food causes me some concern, a while back I took a look at the surprisingly long list of red dyes in a brand of iron pills that my doctor recommended I take. I have no biological need for cadmium, yet it could be found in those iron pills (among other unnecessary things). Apparently, cerium can be used as a non-toxic alternative to cadmium. However, I’ve since found iron pills with no colouring at all.

As a final note: check out these finches playing the guitar.

a new visitor in my backyard

IMG_7469

The Wilson’s Snipe photographed by my husband

My currently dormant garden provides good foraging for any bird interested in invertebrates as the soil teems with worms, millipedes and unwanted slugs. A regular crew of robins hunt across my raised beds for wormy snacks.

Yesterday, I caught a glimpse of a brown bird bigger than a robin. Initially, I thought it was a flicker as they are common in the area. But a flicker on the ground would be odd as they usually drill into trees to find their food (or stop by bird feeders). On closer inspection, the visitor was a bird I’d never seen before. Almost the size and shape as a quail with a brown camouflaged feather pattern. The bird had a ridiculously long beak – great for hunting through soil.

It was a Wilson’s Snipe, normally a shore bird that had somehow found its way to my backyard. It was intent on using it’s beak to find worms. As the snipe foraged, its entire body bobbed up and down almost like a dance. Watching the newcomer was quite entertaining. The bird stayed until dusk, when it shot off into the sky.

As a tangent – hunting snipe is notoriously difficult because they fly erratically and fast. To hit one you must be a good shot, which is the origins of the term ‘sniper’ for a military sharpshooter.

The once plentiful passenger pigeon

A stuffed passenger pigeon

My family kept a few National Geographic World Explorer books for kids in the house while I was growing up. The nature ones were my favourite. I poured over them regularly, fascinated by illustrations comparing the eye sight of eagles to humans and the relative speed animals move. On one page, there was an illustration of a covered-wagon-era family on the prairies looking up at a sky darkened by a flock of passenger pigeons passing by. Even then, it amazed me that a bird once so plentiful is now gone like the dodo and thylacine (Tasmanian tiger).

Once passenger pigeons might have been the most numerous birds on the planet, numbering in the billions. Their spiral to extinction was shockingly fast. The passenger pigeon’s crime was eating grains and other crops, so people went out and systematically killed them, some were eaten, some fed to pigs and most left to rot. At the start of the 1880’s these pigeons were still nesting in the millions. Twenty years later, the last wild passenger pigeon was shot March 24, 1900 in Ohio. Only a few were left in captivity.

The last passenger pigeon died 100 years ago this year. The pigeon, Martha, lived her life in captivity at the Cincinnati Zoo. When she died, Martha was sent to the Smithsonian, stuffed and put on display. There are many passenger pigeons in museum collections, which means genetic material from these birds is available. In the near future, genetically re-engineering recently extinct animals like the passenger pigeon could be possible, but should we?

My husband, who is a curator at the local museum, offered to show me one of the three passenger pigeons held in the museum’s collection. Unlike the flocks containing millions of birds once found in the more eastern areas of North America, passenger pigeons were only rare visitors to BC. For anyone who is curious, the Project Passenger Pigeon site contains a lot of information about passenger pigeons including ranges by province and state.

The photo is of the best preserved specimen at the museum held up by my husband as I wouldn’t dare hold such an irreplaceable specimen. The iridescent rust body reminds me of the colour of the robin’s I see in my backyard, but the body shape is pure pigeon. I kept domestic pigeons around the same time I was pouring over the World Explorer books. I loved the sound my birds made. I wonder if passenger pigeons had the same soft coo?

As a tangent: here is someone collecting the old World Explorer books for the apocalypse.

Turdus migratorius (backyard Robins)

This is not a Robin

How the ordinary can be missed…

Winter is over and I’m delighted to report it’s warm enough to sleep with my window open! My island in the Pacific is temperate, not tropical, so spring warmth is always welcome. With the window open, the first and last thing I hear each day is singing birds.

This time of year, Robins are the ones singing. Around here we don’t have the dainty European ones (they were introduced about in the early 1900s, but didn’t take like the starlings and house sparrows did). Instead, we have a member of the thrush family, Turdus migratorius or American Robin. I’ve read that robins go through puberty once a year (article here) as hours of daylight increase. By this time of year they’re looking for a mate and the search is a noisy affair.

While I was out walking around a local bog, Red-wing Blackbirds were conducting a similar noisy quest as the robins. I heard the blackbirds long before seeing them, a feat my walking companion took to mean I’m an expert on birds. I’m not. Red-wing Blackbirds and Robins are the a few bird calls I recognize (Bald Eagles are another – majestic bird, ridiculous sound). We couldn’t see the birds at first, so we stopped and gazed out into the bog. Eventually, between the dried cattails, we saw flashes of fire-engine* red as the males jockeyed to catch the eye of the females.

I do purposely go out to see birds, but unintentionally I do it poorly. I have a bird identification book and binoculars, which I almost always forget to take with me. I have a check list for local birds that I’m filling out, yet I can’t tell the difference between different species of gulls. I’m a member of the local natural history society and they regularly do outings to watch birds, yet I’ve never gone with them.

There is always at least one Robin in my backyard, so I don’t have to go out of my way to see them. Unlike the Resplendent Quetzal, a bird I traipsed through the jungle in Costa Rica to see, the ubiquitous Robin is easy to ignore. They lack the iridescent green body and brilliant red breast of the quetzal. Even the flashy red wings of blackbirds eclipse a robin’s colouring. A Robin’s breast is the same shade of the liquid that seeps out of a bucket of nails left in the rain. Additionally, most Robin’s wings droop just a bit, giving them a goofy look which is augmented by the bird’s tendency to endlessly pursue their reflection in a window.

Soon, the Robins will sort out who to mate with and the songs will fade. Fragments of delicate blue egg shells will be discarded as the next generation of ordinary Robins are hatched. From my desk, I can watch a Robin bounce over the ground, stop and tug an earthworm out of the ground, a comical procedure. As the bird flies away with a worm in its beak, I’m always left wondering how does the Robin know the worm is there?

* actually, around here, most of the fire-engines are yellow.