Monthly Archives: June 2011

The observer effect

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Close-up of a killdeer (Charadrius vociferus) giving me a little peep (2009_06_03_021880)

When I began voraciously studying physics in high school, the term “observer effect” intrigued me.  It applies to all observational methods, and although quantum mechanics was studied only in the cursory way an AP Physics class can cover any one topic, it put a whole new spin on the premise of the observer effect by showing it remained valid for all observers, even those who weren’t aware they were observing anything (e.g., an electron can cause the observer effect just as easily as a human can).

What the observer effect helps us understand is that the act of observing a phenomenon changes the state of that phenomenon, even if only a small bit.  Consider this: When you take a baby’s temperature, the thermometer must draw heat from the infant’s body in order to measure it, therefore the child’s temperature is changed by the act of observing it.

Although focused on quantum mechanics, a highly controlled study more than ten years ago proved a startling truth: “The experiment revealed that the greater the amount of ‘watching,’ the greater the observer’s influence on what actually takes place.”  But what does this have to do with the environment, saving the planet or nature in general?

Let’s start with this:

It features regularly on lists of things people want to do before they die, but swimming with stingray may not be the life-enhancing experience expected — at least not for the animals.

A new study has revealed that stingray at a tourist hotspot in the Cayman Islands are suffering because of all the human attention. The Grand Cayman sandbank, dubbed Stingray City, is regularly swamped with up to 2,500 visitors at a time, most of whom have paid handsomely for the chance to feed, stroke and swim with the creatures.

The study highlights the risks to animals posed by the growing “wildlife tourism” industry. Experts say wild populations of creatures such as dolphins, penguins and sharks are also affected by increased contact with curious people.

Other examples of the observer effect and how it impacts nature:

Dolphins: Creatures in Australia targeted by tourists are more likely to abandon their young

Killer whales: Whale watching in Canadian waters is shown to reduce animal feeding time

Penguins: Even minimal human contact is shown to double the heart rate of New Zealand’s yellow-eyed penguins

Apes: Mountain gorillas of Uganda, Rwanda and the Democratic Republic of the Congo are known to be susceptible to human diseases

Yet not all manifestations of the observer effect mean obvious harm to nature.  In some cases humans are not seen as predators because they supply food and because they reduce the risk of predation.  Certain species react well to this arrangement, and it allows them to focus more time and energy on reproduction.  Take this video for example:

Simply by being there and observing, the people in the boat drastically change the outcome of the orca hunt, but their impact is not intentional and it is not entirely detrimental.  No one would argue that the penguin thought they were interfering, though it can be asked if the lack of a kill negatively impacted the whale pod, perhaps because of an ill or older member, or a very young member, who did not eat because of the observer effect.

Months ago on the TEXBIRDS mailing list, I remember reading from one woman who gleefully explained how she and another person traveled nearly 2,000 miles over the course of three or four days in order to see two or three rare birds in Texas.  I had to wonder what kind of environmental impact they had in their travels, what with driving all that way, consuming as they went, affecting nature through the act of observation.  If the carbon footprint of that trip could be measured…

Yet it’s part of a growing trend of eco-tourism.  People travel mind-boggling distances to swim with the stingrays, to observe the orcas, to see a rare bird.  They say getting there is half the fun, but it’s also part of the problem—and an integral part of the observer effect.

The rise of eco-tourism is a product of humanity’s sudden interest in the environment as something more than a source of fuel and food.  This newfound appreciation can benefit the environment and the creatures inhabiting it.  It can reduce the killing of wildlife, it can save habitat from destruction, and it can change people and economies in ways that allow humans to make a living by protecting the planet.

The catch, though, stems from the observer effect.  It behooves us to understand the impact we have and to manage that impact as best we can.  Long has been my hope in sharing my nature photography that it would allow people to see and better appreciate what will be lost through inaction, what often goes unnoticed by others until it’s pointed out.  I share this goal with those individuals and organizations that provide eco-tourism services whereby people can experience the breathtaking splendor too long hidden by consumerism.

But we must tread carefully and be certain throngs of appreciative people don’t trample all the life we’re trying to save.  And we must be certain that we do not drastically impact that which we observe.

A great egret (Ardea alba) in breeding plumage hunting in the shallows at sunset (2009_06_04_022126)

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Photos (just to give some eye candy to my little rant):

  1. Close-up of a killdeer (Charadrius vociferus) giving me a little peep.
  2. A great egret (Ardea alba) in breeding plumage hunting in the shallows at sunset.

Observing

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Close-up of a female green anole (a.k.a. Carolina anole; Anolis carolinensis) perched on the patio wall (20080901_11739)

I’m not the only one who’s been busy observing the nesting box I built and placed on the patio.  This female green anole (a.k.a. Carolina anole; Anolis carolinensis) is just one of the critters who took an interest in the goings on by the various bee and wasp species using the box.  Interestingly enough, I’ve seen these lizards try to tackle bees and wasps before, including the giant eastern cicada-killer wasps (Sphecius speciosus).  Though I’ve never seen them successfully grab any bee or wasp species, it tickles me to watch, especially when it involves the cicada killers as those wasps are far too large for an anole to overpower, let alone consume.  But that doesn’t stop them from trying.

As for the nesting box, it’s proven to be one of the best ideas I’ve had.  It’s providing a breadth and depth of observational knowledge that I could never have attained otherwise.

For example, I never knew cuckoo wasps are able to drill holes in dried mud nests in order to lay their egg inside.  They start by chewing at the nest first, perhaps to soften up the dry mud, then they wedge the spines on their gaster against the soft spot and proceed to vibrate at an almost imperceptible speed.  Eventually they’re able to get their prehensile ovipositor into the nest through this tiny, nearly invisible hole.

Also, leafcutter bees (Megachile spp.) are bullies.  When one finished her first nesting tube, she decided to move to the tube next to it.  That tube was already in use by a mason wasp (Euodynerus hidalgo hidalgo).  This resulted in a 24-hour fight—No kidding!  Eventually the leafcutter bee pulled the mason wasp out of the nest and beat her up in midair.  The wasp moved on and the bee set about dislodging and ejecting the existing nest material from the tube.  I now have little piles of sand and a lot of paralyzed caterpillars spread around the patio (which has attracted hordes of acrobat ants [Crematogaster laeviuscula] to clean up the critters).  Meanwhile, the mason wasp has moved to a new tube where she’s already begun a new nest (technically it will be her third because she finished her first one a few days ago and her second one now has a leafcutter squatter).

Much to my surprise, the nesting critters sleep in the tube they’re working on.  I didn’t realize this until one morning around sunrise I knelt down and leaned in close to see what was what inside the tubes.  One of the mason wasps charged to the tube entrance.  I had no idea!  In the days since, I’ve seen that the leafcutter bees and both mason wasp species do this (the mason bee tubes are too small to see if anything’s moving inside them).  And though they’ll charge to the front of the tube in a show of defiance, it’s more bluster than anything else; as solitary stingers, they’re not particularly aggressive unless you manhandle them.

Finally, size really does matter.  The leafcutter bees are large; in fact, they’re too large for all but the largest nesting tubes.  The mason wasps and mason bees (Osmia sp.), on the other hand, are small and/or slender enough to use any of the tubes.  The first time I saw a mason wasp (Euodynerus megaera) land on one of the smallest holes, I quietly thought she’d soon learn she would need an upgrade.  But I was the one who would soon learn.  She promptly folded back her wings and slipped inside as though walking through double doors.  Impressive!  Euodynerus hidalgo hidalgo is also small enough to use those holes, and certainly the mason bees are small enough to do so.

When it comes to species seen, here’s what I can tell you:

  • Mason wasps (Euodynerus hidalgo hidalgo)
  • Mason wasps (Euodynerus megaera)
  • Leafcutter bees (Megachile sp.)
  • Mason bees (Osmia sp.)
  • Cuckoo wasps (Chrysis coerulans), targeting dirt dauber nests and not the nest box
  • One, if not two, other cuckoo wasp species targeting the wasps and bees in the box
  • At least two species of chalcidoid wasp, though they’re too small and move around too quickly for a good look—at least thus far
  • And the usual suspects: black and yellow mud daubers (a.k.a. mud wasp; Sceliphron caementarium) and common potter wasp (a.k.a. dirt dauber; Eumenes fraternus), not to mention the paper wasps I keep having to kick off the patio

Oh, and when it comes to the green anole’s fabulous colors, that show is courtesy of the “Oh no!” hue that filled the sky last Tuesday just before our tornado outbreak.  Yes, the sky took on that ominous color that just shouts danger is on its way.  In the end, that evening we had at least ten confirmed tornadoes in and around the DFW metroplex.  Rest assured we spent some of that time huddled in the bathroom during the overlapping tornado warnings that stretched on for two hours and were accompanied by three blasts of the warning sirens.  Still, just before it got ugly, the combination of threatening sky and deep shadows really made for some beautiful colors on otherwise ubiquitous objects, lizards included.