Birds of My Neighborhood: Geotripper Explores the Home Base on National Bird Day

Cedar Waxwing (Bombycilla cedrorum)

I'm told that today is National Bird Day (thanks, Randall), which was convenient to today's post since I was already collecting pictures of birds from my last two days of neighborhood exploration. It was meant to be an addition to my post several days ago describing the surprising diversity of birds in my home town, despite the winter chill. The Great Valley of California turns out to be quite the refuge for winter survival of a great many avian species. We are far enough south to avoid the frigid chill of arctic storms, and most of our storms are gentle compared to the blizzards experienced in other parts of the country (with the occasional exception, of course).

Cedar Waxwing (Bombycilla cedrorum)

But really, birds in a geology blog? What connection could there possibly be with the study of rocks, minerals, and fossils? Oh, yeah, fossils. Birds have been an important part of the web of life on this planet for more than 100 million years, and were the last of the major families of terrestrial creatures to emerge. They are literally the last dinosaurs, but as such they are particularly successful and diverse dinosaurs, and most certainly not a failing evolutionary dead end. And they apparently almost displaced mammals as the apex predators in the terrestrial environment several tens of millions of years ago.

American Robin (Turdus migratorius)

After the "regular" dinosaurs met their demise at the end of the Cretaceous Period (possibly as a result of an asteroid impact), the subset of feathered avian dinosaurs were some of the survivors that expanded and evolved to fill a world with many empty environmental niches. Mammals were quickly evolving to fill those same niches, and for a while there were some gigantic land birds that were the top predators of their time. Eventually their places were taken by large mammals and crocodile-type reptiles, but the birds mostly took to the air and became one of the most diverse vertebrate animal groups in the world today.

Yes, you "mock" me now, but imagine me being 10 feet tall. That would change your tone in a hurry...

Today, birds are an integral part of any terrestrial ecosystem, and their relative health is a barometer for all life on our planet. There is a great joy in observing the incredible diversity of these fascinating creatures, but the diversity and future survival of these animals is threatened from habitat destruction and hunting. That's probably more true in the Great Valley of California than for about any other place on the planet.

Western Bluebird (Sialia mexicana)

The Central Valley (the term is interchangeable with Great Valley) is one of the world's great savanna-grassland-riparian habitats and was once a paradise for numerous bird species and other animals. The vast wetlands were historically a critical stop on the migratory flyway for hundreds of species. Unfortunately for the birds, the rich soils and ample water supply from Sierra Nevada rivers have meant that most of the valley has been co-opted by humans for agricultural development. Only 5% of the original habitat still exists. This has meant huge changes in the ecosystem, with many species that have disappeared, and others that have prospered. 

Oak Titmouse (Baeolophus inornatus)

Humans added all kinds of mayhem by introducing new bird species for spurious and stupid reasons. One of the worst: a man in the 1890s who resolved to introduce to the New World all the birds mentioned in the works of Shakespeare. He arranged for the release of several hundred European Starlings in Central Park. They have since spread across the continent like a plague, displacing dozens if not hundreds of species of native songbirds. Other birds arrived as pets which subsequently escaped (flocks of parrots live in the LA Basin, for instance).

Black Phoebe (Sayornis nigricans). Identification thanks to Callan Bentley (Mountain Beltway) and his friend Seth.

Despite the horrific pressure brought to bear on the native species of California, there are many bird varieties still to be seen in the Great Valley. I have become aware of this delightful fact over the last few weeks as I explored my own local neighborhood with a new camera with a nice optical zoom. We've always had a feeder in the backyard, which caused me to think that the only local birds were goldfinches, house finches, scrub jays, and mockingbirds. A new habit of walking around the nearby cow pasture has revealed a real menagerie of beautiful and interesting species.

Scrub Jay (Aphelocoma californica)

So today's post (and my post from several days ago) is a celebration of National Bird Day, with fifteen species that I was able to photograph in just two days of strolling around my neighborhood. Some I've seen before, and many I have never noticed. I never would have guessed that two, and maybe three species of woodpecker live on my block!

Northern Mockingbird (Mimus polyglottos)

Some of the birds are skittish and shy, and others look at you and don't give a rat's posterior that you are standing there photographing them. And then there are the crows and ravens. You look at them and you can see them thinking and hear them talking about you...they are said to be the smartest of all birds, and I pretty much accept that way of thinking.

Nuttall's Woodpecker (Picoides nuttallii)

And never forget: these little fellows are dinosaurs. Only they're smarter...

Dispatches from the Road: Feeling Detached in Saguaro National Park

Had a few spare moments from family matters while in Tucson, Arizona today, so we headed out to Saguaro National Park and Tucson Mountain Park, which are both on the outskirts of the city. I'm not overly familiar with the area's geology, so it was a real learning experience. I really wish I had more time here!

The first thing that happened is that this mockingbird got in the way of my picture of the far mountain ridge. There was a beautiful bright red cardinal, too, but I couldn't convince it to block the scenery for me...

The Saguaro cacti kept getting in the way of the shots of the rocks, too, but I guess they provide some sense of proportion. The mountain ridges in the Rincon District of Saguaro National Park looked vaguely familiar to me, forming a roughly domal shape.

A convenient pull-out confirmed my suspicions...these rocks were reminding me of Death Valley...specifically the Black Mountains on the east side where several detachment faults are prominently exposed. Detachments are evidence of extreme extensional forces in the crust of the Earth. As the younger overlying rocks slip off the underlying ancient rocks, the rocks bow upwards forming the dome-like outlines. Deeply deformed rocks called mylonite are found along the fault contacts

The younger overlying rocks actually ended up on the other side of the Tucson valley. They make up the rocks exposed in Tucson Mountain Park, which we visited briefly while looking for a place to watch the sunset. Much of the rock is volcanic rhyolite, formed during intense caldera eruptions similar to those that produced Yellowstone and Long Valley (in California). The sharply jointed rocks form prominent peaks that do a nice job of catching the last rays of the sun.

 I am almost never disappointed by an Arizona sunset...

The Saguaros always provide a nice frame for pictures of the sky and horizon...almost a cliche that you've seen a thousand times in calendars, but there is nothing like being there. I couldn't stop snapping pictures, and if I didn't have a camera, I would have sketched. And if I didn't have a sketch pad, I would have scratched images on the rock, much as the original inhabitants of this country did thousands of years ago. It's that pretty.

From Gates Pass, the view was stupendous. We watched until darkness, and headed back down into Tucson for dinner. Gotta get some sleep, because tomorrow we are headed to the Grand Canyon! To research the summer field trip, of course....

For some information on the geology of Saguaro National Park and the adjacent Tucson Mountain Park, check out this pdf file.

Theropods in the Backyard: Dinosaurian Drama on my Porch

Apologies to Harper Lee, but if she had come to have known the mockingbird in my backyard, she would have called her classic story "To Kill a Yellow Finch". Or, she would have written a totally different story under the original name, a horror novel that Alfred Hitchcock would have been comfortable making a movie from.

I don't want to make light of Lee's novel. I watched the movie "To Kill a Mockingbird" the other night, and was reminded again of its great emotional impact. In this day when bigots are once again feeling free to spew their hatred on the right-wing airwaves, it was a reminder of what a fragile thing justice and equality is in our society, and how easily we could lose it.

On the other hand, that mockingbird in our backyard is more reminiscent of the velociraptors in "Jurassic Park". No hauntingly lyrical song from this one; it's a screech that would put cold fear into anything small enough to be hunted. It has a bravado that has to be seen to be believed. It's attacked our cats, our dog, my wife, and my son. I think I'm the only one big enough to make it think twice.

On the other hand, there's the T-rex or Allosaur of today's dinosaurian world, the hawk. This juvenile Redtail (?) was hanging out in my mom's backyard these last few weeks. It still begs for food from momma, just like any teenager, but is getting better and better at flying, and soon will be striking fear into the local rodent population, just as its ancestors have been doing for 200 million years.