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CALIFORNIA VERSUS COLORADO: IT IS DIFFERENT OUT THERE! (HOW MANY HUMANS ARE ON YOUR LIFE-LIST?)

By Nic.Korte

Humans are relentlessly mobile and adaptive. We go everywhere. We breed everywhere. That’s why there is only one species of human. Our DNA shows it. In birder’s parlance, everyone has the same life-list when it comes to humans--one!

On the other hand, some folks can be quite exorcised about their life-list of birds. I can be equivocal about there being one species of homo sapiens, but with birds it isn’t so easy. I can tell you there are approximately 10,000 species. But why is it “approximately?” Don’t we know?

I was thinking about this on a recent trip while driving to and from Southern California. The landscape is mostly familiar between Western Colorado and St George, Utah, but then it changes. The Mojave desert remains a formidable barrier—especially in mid-summer when temperatures frequently exceed 110 degrees. Sure, we zip across it in about five hours in our air-conditioned cars. But a mid-afternoon breakdown, say between Primm, Nevada and Baker, California, could still be a dangerous situation. And, if you are a bird with no desert adaptations? Well, you will just stay on your own side.

The Mojave, in consort with some of the mountains that lie north-west across the Western US, is a barrier many birds can’t cross. Sometime in the distant past, maybe when times were not so hot and dry, there was more interaction between east and west. Eventually, some originally-identical species, became isolated. Because evolution never stops, the isolated populations began to diverge and soon took on a slightly-different appearance, learned to live in a different habitat, and were no longer able to breed with their once close relatives. These facts have long been known, but it hasn’t been until recent advancements in the use of DNA testing and song recording, that scientists have been able to prove that some very similar appearing populations are, in fact, separate species.

All this means that if you are the type of person who lovingly adds another bird to their life list—now is a good time. A lot of species are being split. [That’s not to say that only “splits” are happening. There are also a few “lumps.” In these cases, birds with different appearances are now shown to be, like humans, superficially distinct in appearance, but with no other discernible differences.]

Here in conservative Western Colorado, many would like to consider Californians a separate species of human, but it just isn’t so. Maybe if each side would stay put for a few millennia, something interesting might happen, but that isn’t the human way. Many birds, on the other hand, have been isolated long enough for differences to arise.

In the past month, the international group that decides such things, decreed that our Western Colorado Scrub-Jays, are now Woodhouse’s Scrub-Jay. Those in California, get to keep the old title of Western Scrub-Jay. Wow, just like that. I added one to my life-list.

(Woodhouse's Scrub-Jay by Jackson Trappett.  On the west coast, the Western Scrub-Jay has a sharply  defined blue breastband and is whiter underneath)

Our annual family vacation to Southern California usually includes plenty of time for me to go look for some birds. Besides brushing up on shorebirds, which are almost always in scant supply in our area, I can look for those species specific to the West Coast. Scrub-Jays are easy-to-see, and I had already seen plenty in both locations, but a few years ago, there once was a sparrow known as the Sage Sparrow.

The Sage Sparrow is no more having been split in 2013 into the Sagebrush Sparrow and the Bell’s Sparrow. This split found me early on Sunday morning hiking a ridge in the Sycamore Canyon Open Space Preserve about an hour north and a little east of San Diego. Bell’s Sparrows allegedly live here.

Sparrows, being sparrows are not so easy to see. Most like to hide on the ground or in bushes. These two species are also very similar. The Bell’s Sparrow has fewer or no streaks on its back, has somewhat bolder coloration, and has a broader and darker stripe on its throat. The differences are subtle enough that separating the two can be difficult. For that reason, I was looking for Bell’s Sparrow on its breeding grounds. (I admit, I can be a lazy birder—best to look where only one of the two closely-related species might be present.)

If I want to find Sagebrush Sparrows in Western Colorado, I know exactly what habitat to look in: “one-to three-foot high sagebrush that blankets hills and basins in large, unbroken stands” (Birds of Western Colorado, p 168). I looked around the Sycamore Canyon Preserve—no sagebrush. I was hiking in California Chaparral—an ecoregion under much pressure from development.

Even though I wasn’t looking for sagebrush, nothing else looked right either. I had already hiked more than a mile on a ridge. The plants I saw were too large. Some areas seemed too lush with too much diversity. A larger hill loomed in front of me. It was hot. “Oh well, I may as well see what’s on top.” Once on top, there was a moment of sudden recognition. Not sagebrush, but the southwest slope in front of me seemed structurally identical to where I find Sagebrush Sparrows in Western Colorado: one- to three-foot high shrubs in a near mono-culture.

It wasn’t long before I saw at least three Bell’s Sparrows including one close enough for a photo. The dominant plant here was chamise. I learned later that stands of pure chamise generally occur on hot, dry, south-facing slopes in areas of rough topography just like this one. As for the birds, they seemed a bit darker with a better defined throat stripe. 

(Sagebrush Sparrow on left--with distinct streaks on the back.  The Bells' Sparrow {right} has no back streaks but has a more distinct and broader throat stripe.)

Over many years, these sparrows have adapted to similar, yet different, habitats, and have become different species. Then I considered, “if humans ever did colonize Mars, how long would those on earth have to stay away until the life-list for humans would reach two?” Maybe we’ll know the answer in a few million or billion years!

This post provided by Nic Korte, Grand Valley Audubon Society. Send questions/comments to audubongv@gmail.com. [To learn more and to participate in the activities of Grand Valley Audubon, please see our website at and “like” us on Facebook!] 

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