Juvenile Western Bluebird at the Black Diamond Mine

I still catching up on the richness of birds that I've seen and photographed this summer. Back in May our Geology Club took a tour of the underground mines at Black Diamond Mine Regional Park in the Pittsburg-Antioch area of the Sacramento Delta.

As we walked up the valley towards the mine entrance, I saw a LGB (little gray bird) that I couldn't immediately identify (there are lots of little gray birds that I haven't yet learned to identify quickly). After watching it move around, I began to suspect it was a baby rather than an adult, so I started looking for the mother.

Pretty soon I spied momma, and realized that the little one was a Western Bluebird (Sialia mexicana), one of my favorites, judging from the number of posts I've put up (this is the 13th).

Black Diamond Mine was a source of coal and glass-making sands a century ago (California is not known as being much of a coal mining region, but the energy demands in the late 1800s led to the use of even marginal coal deposits). The park is a pleasant place for hiking and bird-watching. Many of the scars of the mining have faded away.

Violet-Green Swallow at the Black Diamond Mines (and a Mono Lake bonus)

Tropical birds are so colorful, and I don't really know why (I'm sure display has a lot to do with it, but what about defensive camouflage?), but when they visit our region, I sure appreciate the splash of color. The Violet-green Swallow (Tachycineta thalassina) is one of those tropical visitors in our region in the spring and summer.

I saw this swallow on a geology club field trip to Black Diamond Mines Regional Park back in May. If you are wondering about the name of the park, it refers to coal, not gemstones. It may seem strange that an old coal mine (they also mined sand for glassmaking) should be a park, but time heals many scars. There are underground tours in the old mines, but the oak woodland and wildflowers are wonderful as well.

As I was going through the pictures from last May, my mind was jogged. I had seen these birds before, long before I really was doing any kind of birdwatching. I was at Mono Lake in the eastern Sierra Nevada in 2010, and the swallows were catching flies and perching on the tufa towers.

I was fascinated at the time, and for all I know, these pictures may have had something to do with awakening my interest in the birds that were sitting around on my beloved geological outcrops.