Tuesday, September 25, 2012

The book I haven’t read

my copy looks exactly like this
This week marks 50 years since Rachel Carson’s ‘Silent Spring’ was published.

I care about the environment in part because it's the only environment we have to support us, thus it's our lifeline. I agree with Carl Sagan when he wrote “the simple fact is that we are performing unprecedented experiments on the global environment and in general hoping against hope that the problems will solve themselves and go away.” I’ve been aware of Rachel Carson’s book and how it is credited with starting the environmental movement since I was in high school - yet I’ve never read it (yes I should read it - as soon as I find a copy in a used bookstore I’ll pick it up).

I can’t comment on ‘Silent Spring’, I have however, read another book by Rachel Carson, ‘The Sea Around Us.’ My grandfather gave me his copy of the book when I switched into oceanography for my undergrad. In the front cover the inscription says ‘this book is presented to H.B. Hunt as an award for excellent meteorological observations carried out in S.S. Lakemba on a voluntary basis during the year 1951.’ He must have been presented the book when it was brand new as it was published in 1951. By the early 90’s, it looked slightly ratty on my book shelf and I didn’t read it then, but I kept it. A few years ago I realized who the author was, so I decided to pull it out and finally read it.

The acknowledgments read like a who's who of early oceanography - all names of people who made major contributions to the field. In addition to her background in marine biology, she did her homework. I found it an easy read that made the ocean seem magical. Consider her description of the tides:

There is no drop of water in the ocean, not even in the deepest part of the abyss, that does not know and respond to the mysterious forces that create the tide … no other force that affects the sea is so strong.

Or surface waves:

It is a confused pattern that the waves make in the open sea – a mixture of countless different wave trains, intermingling, overtaking, passing, or sometimes engulfing one another; each group differing from the others in the place and manor of its origin, in its speed, its direction of movement; some doomed never to reach any shore, others destined to roll across half an ocean before they dissolve in thunder on a distant beach

What I also enjoyed about the book is what she didn’t mention. Places like hydrothermal vents hadn’t been discovered yet - so the belief at the time was that the abyss was barren of life. Ideas like plate tectonics were not yet widely accepted so, the ocean floor was presented as static. We have learned so much in the time since the book was published.

Note: the picture came from Wikipedia

Thursday, September 20, 2012

Aliens for dinner

Not the alien I mean
Sounds like I invited some extraterrestrials over to share a meal but, what I really mean is eating invasive species as a form of revenge against the damage they inflict on our native species.

As people move around, we tend to take critters (and plants - which I’m not going to discuss) with us. Rats and cats have been introduced across the globe, both of which have been known to decimate bird populations - especially on islands where birds have lost their ability to fly. Pigs were deliberately left on tropical islands by passing sailors to provide future food.

Sometimes animals are intentionally introduced as a means to fix a problem. For example, Australian sugar cane crops were being decimated by cane beetles, so in 1935 just over 100 cane toads were introduced to control the cane beetles. The cane toads adapted well to their new environment, now there are over 200 million - however they didn’t control the cane beetles. Instead cane toads caused all sorts of other problems as they are toxic to the animals that try to eat them.

Want to make a buck? 
How about introduce a critter that produces a luxury product, like beaver fur. In 1946, 50 beavers from Canada were introduced to the southern tip of South America for just this reason. It turned out great for the beavers as there were no predators to worry about. The beavers went on to do what beavers do - gnaw down trees and build dams. Unfortunately, the forests in that region can’t handle beaver damage like North American forests can, so the damage is extensive. Active programs are still underway to remove the beavers.

Not all introduced species create these kind of problems, however there is always a risk that a local species will be displaced by the newly arrived animals. The result is a loss to our global biodiversity as our world-wide ecosystem is becoming more and more homogenized.

In my part of the world, we have lots of introduced species (tropical areas often have more - Hawaii and Florida are perhaps the hardest hit with alien invaders). There are green crabs, manila clams, carp, house sparrows and grey squirrels to name a few. Another that has become ubiquitous in North America is the European Starling. These noisy birds like open country - like orchards and grain fields. They often flock together in massive flocks where they scour the area for fruit and insects to eat. They indiscriminately eat crops intended for human consumption which has put them on the hit list of many farmers. They also out compete local birds, for instance swallow species like the purple martin, for nest sites.

Why would anyone introduce starlings? 
In the late 1800’s, Eugene Schieffelin decided to introduce every bird mentioned in Shakespeare's works into North America. As part of this odd plan, 60 starlings were released in 1890 into New York’s central park. Now, there is an estimated population of 200 million.

So what can be done? 
One option is to eat the invaders. I was at an event recently put on by the Penticton Museum and Archives for the opening of the traveling ‘Aliens Among Us’ exhibit created by the Royal BC Museum. The exhibit highlights alien species in BC. At the opening, breaded and fried starling breast was offered - the meat was dark and gamey, reminiscent of goose, and was quite good. For Okanogan fruit growers, eating starlings must be a delicious form of revenge.

It would take a lot of effort to harvest enough starling breast to make a full meal. I’ll just keep the idea in the back of my mind in case there is a zombie apocalypse and starlings are all I can catch.

As a tangent - people are not considered ‘aliens’ in this context because people tend to move themselves around (i.e., natural dispersal) - although governments might label people as aliens for various reasons. By this same logic, extraterrestrial aliens would only be considered aliens if they hitched a ride to earth on a space shuttle instead of their own spaceship.

Tuesday, September 4, 2012

Examples of iridescence from the fall fair

I caught these two beauties showing off their iridescent plumage at the fall fair. It always amazes me that such a range of colours can be produced from an optical trick.