A Bird’s Gotta Eat

Image

Red-naped Trogon by CK Leong

Imagine that Housing & Dining closed the salad bar at the servery. Then they shut down the grill. We would have to move from our main sustenance of curly fries and hamburgers to alternative food–the dreaded entree buffet. While this is most likely not a student’s preferred pick, the food served here is often healthier and higher energy. When people are prevented from eating a specific type of food, their diets and habits change faster than the weather around Houston.  

While students at Rice University are lucky enough to have plenty of food options available, the birds of the forests of Borneo are not so fortunate. The widespread use of logging in Borneo has sanctioned off a good portion of a bird’s diet-the fruit from the trees. Even if the birds are insectivores or omnivores, meaning that they like to munch on some tasty bugs or small animals, they are still affected by logging because they’re prey has nothing to eat. Instead of starving to death, however, studies show that species with flexible meal plans will gobble up whatever is at the next highest energy level. Just like people rank food based on nutrition, the natural world is ranked by the amount of energy packed into food. The higher up the food chain, the higher the level of energy.  The prey of choice for these birds becomes insects if they had previously eaten fruit, or insects that eat other insects, like spiders. Yum. Just like how students will grumble over to the entree buffet to eat a potentially higher-energy meal at the expense of preference, birds in the tropical forests of Borneo eat higher energy food when their preferred food source is decimated due to logging. 

So all of this logging in forests is a good thing, right? Doesn’t it make a more energy-rich ecosystem? Wrong. Not all the birds are as flexible in what they can eat. Continuing the servery metaphor, the more picky students just give up and move-off campus. But that isn’t necessarily an option for the birds. They just die. About 20% of the birds are not as resilient in their diets, so they starve to death. Ok, so not all of the birds suffered the same, soap-opera tragedy ending in starvation. However, the  birds that did survive turned out to have less flexible ranges of food at higher energy levels. Scaling up the food web made the birds a little less open-minded. With a bunch of picky birds around, the ecosystem as a whole is on the brink. 

So what does this all mean for conservation? As the birds are eating at higher energy levels, their diets becomes much less flexible. As we’ve seen before, birds that have strict diets don’t tend to do so well when catastrophe strikes. This makes the ecosystem of the Bornean forests more fragile then ever. If, say, a huge fire comes along, the likelihood of the “dieting” birds surviving is slim to none. The fact that logging leads to limited diets in birds makes the lumber industry a huge threat to the ecosystem. Because of the potential for a massive breakdown of the ecosystem, protecting logged forests should be a conservation priority. 

Sources: 

Article:

EDWARDS, DAVID P.,  WOODCOCK , PAUL, NEWTON, ROB J., EDWARDS, FELICITY A.,  ANDREWS, DAVID J. R.,  DOCHERTY, TEEGAN D. S., MITCHELL, SIMON L.,  OTA, TAKAHIRO, BENEDICK, SUZAN, BOTTRELL, SIMON H., HAMER, KEITH C. (2013), Trophic Flexibility and the Persistence of Understory Birds in Intensively Logged Rainforest. Conservation Biology, 27: 1079–1086. doi: 10.1111/cobi.12059

Image:

By CK Leong (Red-naped Trogon) (http://borneobirds.com/red-naped-trogon/

http://borneobirds.com/red-naped-trogon/) via Google Images

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