Breathing. It’s something we normally  do 12-18 times every minute. But just for a moment - pay attention to the flow of air. Take a deep breath. Hold it for five seconds. Then slowly breathe out. You have what is called a bi-directional flow of air to and from your lungs.
According to Dr. C.G. Farmer, associate professor of biology at the University of Utah, this is also described as a “‘tidal’ breathing pattern: Air flows into the lungs' branching, progressively smaller airways or bronchi until dead-ending at small chambers called alveoli, where oxygen enters the blood and carbon dioxide leaves the blood and enters the lungs. Then the air flows back out the same way.” Read full press release, click here .
Most, but not all, animals have this breathing pattern. Birds do not, they have a unidirectional pattern. As Dr. Farmer describes it, “their breathing is dominated by one-way airflow in the lung itself. The air flows through the lung in one direction, making a loop before exiting the lung.”
Here’s how it works: birds have 2 lungs AND 9 air sacs. Their lungs, like ours, are involved in the exchange of oxygen and carbon dioxide. But their air sacs funcion like bellows, moving the air along as they expand and contract. Click here  to see an animated description of how this works.
Why would this breathing pattern be useful for birds? Do you remember the last time you flew in an airplane, when you heard the safety lecture: In the event of a loss of cabin pressure, oxygen masks will drop...”? What’s true for us is also true for birds - we both need oxygen. But there is less oxygen at higher elevations. Bi-directional breathing patterns are generally less efficient than than unidirectional patterns.
To visualize this, let’s try a mind experiment. Imagine that you are standing on the sidewalk in front of a two-way street (a bi-directional pattern). Both lanes are jam-packed with cars, an equal number travelling north and south. The cars moving north contain oxygen while the cars moving south contain carbon dioxide. Now imagine the same street, but this time, it’s a one-way street, with only 1/2 the number of cars. Both lanes of traffic are moving north, so all the cars contain oxygen. Here’s the question:
Q. Which traffic pattern carries the most oxygen-containing cars?
A. Both patterns contain the same number of oxygen-containing cars. Even though the total number of cars on the one-way street is half that of the two-way street, the number of cars containing oxygen is the same.
Free Birding App. For those of you who are looking for a good birding app for your Apple cellphone or iPad, the Cornell Lab of Ornitholgy is offering a free app. Click here  for more information.
Upcoming Santa Clarita Outdoor Events:
Saturday, February 15, 8-10 am. Winter Weather and Bird Behavior. On the coldest days of the year, birds adapt to keep warm in many ways. Learn about some of the behavioral changes that take place. Beginning birders are welcome. Binoculars optional. Meet at Towsley Canyon’s front parking lot. Click here  for map and directions.
Trail Maintenance Schedule. Come join our volunteers as they help maintain our trails. Contact Steve at firstname.lastname@example.org  for time and place.
Wednesday mornings, February 5, 12, 19, & 26.
Saturday mornings, January 15.
New trail maps available. If you’d like to explore a bit on your own, the City of Santa Clarita has a website with trail maps  of our local open spaces.
There’s also a new website for bicycle riders .
Ask Dr. Norm : Do you have questions about the flora, fauna, animals, rocks, etc. in our Santa Clarita Valley? Here’s a place for you to ask your questions. Dr. Norman Herr, Ph.D., is a professor of science and computer education at California State University, Northridge.
Tell Us About Your Hike : Here’s a new website where you can post pictures, provide feedback and make suggestions about the City of Santa Clarita’s trails and open spaces.
You can listen to stories like this every Friday morning at 7:10 a.m. on "The SCV Outdoor Report", brought to you by your hometown radio station KHTS (AM1220) and by the Mountains Recreation and Conservation Authority.
Or check out our Facebook page - L.A. Mountains .