Turkey vultures have returned to Front Range

Some people watch for the first robin of spring. In Capistrano, they look for the return of the swallows. I know it’s spring when the turkey vultures return to the Front Range of Colorado. (https://amylaw.blog/2013/04/08/it-must-be-spring/)

Turkey vultures are big birds — the biggest you are likely to see, with the exception of an eagle or an American white pelican.

You’re not going to mistake a vulture for a pelican. The others are a little more problematic.

They are big, dark bird with translucent (almost see-through) trailing wing feathers, and a red head.

I have the most trouble telling a turkey vulture from bald or golden eagles. Although golden eagles may hold their wings in a slight “V”, most often they hold their wings flat.

A turkey vulture soars with it’s wings in a slight “V”, often called a “dihedral”.

Turkey vultures are also “tippy” when they fly — they are so light that air drafts bounce them around. Eagles are not “tippy”. It’s beneath their dignity.

And neither a bald or nor golden eagle have the translucent trailing wing feathers.

Swainson’s hawks, or a broad-winged hawks are both tippy and fly in a V. But both these hawks have shorter, broader wings, and are smaller. They also often brownish-red and have white markings on their wings or bodies.

You might confuse it with a black vulture, but black vultures just seem smaller overall — shorter wings, much shorter tail, with a dark grey head. Plus, black vultures are limited to the southern US down into South America. I have to travel south if I want to see a black vulture.

It’s been a long, hard winter. I hope you enjoy your first signs of spring, whatever they are!

Spring storm brings cold, wet; hummers come to feeder

As a violent spring storm crosses the country, the temperatures along the Front Range of Colorado are hovering in the low 40 degree range, and may dip below freezing tonight, and the drizzle we’ve had all day may turn to snow.

Yet hummingbirds have been in the area for a month. These little guys have to burn through a lot of energy to survive a cold wet storm like this.

Fill up, little hummer! We’ll keep it coming for you!

Life in the mountain shrub community

Another hike, a bunch more fun photos. One of the big reasons I like walking is because I go slow enough to see interesting things.

Side-blotched lizard maybe 3

Side-blotched lizard.

If I’d know blotchiness on the side of the lizard would be diagnostic, I would have tried to get a shot.

Side-blotched lizard maybe 1

The slit on the lizard’s head is not a gill, as I keep thinking it is, even though I know better. Reptiles don’t have gills, they have nostrils and breath air.  The slit is the lizard’s ear.

 

Yellow brested chat

Yellow-breasted chat.

Yellow-breasted Chats look like lemon-breasted robins. But instead, they are overgrown wood-warblers, a family that includes birds like the Virginia warbler or Wilson’s warbler. Don’t recognize the names? That’s because they are too small to see easily, usually around 5 inches long, or smaller, and they prefer denser forest. Yellow-breasted chats, on the other hand, are around 7 1/4 inches long — robin-sized — and live in open shrubland.

mountain gentian-1

Fremont geranium

Fremont geraniums were all along the trail. Very nice.

Sharp-shinned hawk misses flicker for lunch

The gregarious band of little bushtits took off in a burst of feathers and cheeping alarm calls.

OLYMPUS DIGITAL CAMERA

I looked up just in time to see a Northern flicker shoot out of the top of a tree, with a sharp-shinned hawk in hot pursuit. Luckily for the flicker, the hawk had made its move too soon, and given the flicker a head start the predator couldn’t overcome.

Northern flickers spend all year in the wooded areas of the Front Range of Colorado. They are in the woodpecker family, but they spend as much time on the ground as they do in trees, stabbing their big sharp beaks into the soil in search of insects.OLYMPUS DIGITAL CAMERA

Sharp-shinned hawks are woodland predators. They, too, live year-round in Colorado woodlands, and in fact they cover most of North America.  Most of their diet comes from birds that they surprise and chase through the trees — exactly what I saw today, except that the flicker got away.notice the long notched tail and dark cap on head

Air Inversion Traps Cold Air, Pollution

Normally on Green Mountain you get a wonderful view of Denver.  Often the air is so clear that we can see the terminals of DIA across the Platte valley.  South Platte Valley Clear Day_edited-1
Not yesterday.
Yesterday, we saw a thick grey smudge across the skyline – pollution held in place by an air inversion.  We all know what pollution is, and we often hear about an air inversion.  But what is an air inversion, really?Smog in South Platte Valley
Typically, air temperature gets colder the higher up you go, because the thicker atmosphere traps the heat at lower levels.  The warm air eventually rises, mixing the air.
Once in a while, though, the air becomes very stable because the ground is cold too, such as when it is covered with snow.  When this happens, there is no mixing because no warm air is rising.  Then the cold, dense air on the nearby slopes can slip down underneath the cap of relatively warm air above.  Now, the usual cold-on-top-warm-on-bottom layers are reversed in an air inversion. Air Inversion_edited-2
Air inversions are most common in the winter, when the air is coldest and most dense and snow insulates the ground.  Land features such as mountains, hills and valleys can trap the colder air, and funnel it into low lying areas.  This means that the slopes of hills or mountains are often  warmer than the frigid bottom lands.
Air inversions are common in the South Platte Valley that holds Denver,  but very cold temperatures and deep valleys means they occur more often and for longer in the mountains. North, Middle and South Park, the San Luis, Eagle and many other mountain valleys often have excellent conditions for air inversions.  Fraser has earned the nickname “Icebox of the Nation” because of them, while Maybelle, in the Yampa River Valley, holds the dubious distinction of having the coldest temperature on record in Colorado of -61 o F on February 1, 1985.
To add to the problems, the inverted air can act like a lid on a pot, keeping the cold air trapped inside the valley.  If the cold lower air is humid, we have fog, if it becomes polluted, we have a high pollution day.