Diario de mikaelb

Four people joined me this morning for the monthly group walk on Hill Country Conservancy's Nalle Bunny Run wildlife preserve. Here are some highlights.

Before the group arrived a pair Summer Tanagers flew in with some interesting behavior. The male was in heavy molt, and he was "whisper singing" which is singing a quieter version of his normal song. See how uneven his tail feathers are in this photo:

A female joined him and she was quivering her feathers like I often see begging juvenile birds do. I don't know if this was a young bird still begging from its parent or the male's mate reinforcing their bond. Here they are together:

After the group arrived we enjoyed a slow walk covering about 1.5 miles and touring most of the preserve. Birds were present but mostly heard rather than seen. Here are some fun non-bird observations we made.

We found these armadillo tracks in the road shortly after we started:

This tiny Green Anole that we found by the graveyard must've been newly hatched:

One of several dragonflies we found was this beautiful male Roseate Skimmer:

I was excited to find this White-striped Longtail butterfly feeding on Lantana flowers:

One fun bird observation we made was this female Summer Tanager, chasing, catching, and eating a red wasp!

By the end of the walk I had recorded 22 species of birds. Here's our complete eBird list.

Here are a few more photos on Flickr.

And attached are the same photos as iNaturalist observations.

On my way back from the Davis Mountains Hummingbird Celebration last week I stopped at a neat looking access spot on the Pecos river, just east of Iraan (pronounced "Ira Anne") on highway 190. It was a clear hot day, the temperature was over 100 degrees at about 1:15 PM when I stopped there. Soon after I parked by the river I was glad I had my water shoes with me because the water was clear and flowing over a rocky bottom. I wanted to wade in it!

I was surprised to find a few species I normally associate with the Texas coast. Soon after I got out of the car I spotted a few Marl Pennant dragonflies "obelisking" on high branches:

Obelisking is a behavior dragonflies use to regulate their heat. In sunny hot conditions they will often point their abdomens straight up at the sun to minimize the surface area presented to the sunlight. This keeps them a little cooler.

Soon afterwards I noticed many beautiful little fishes with sparkly blue napes and vertical stripes on their sides all over in the shallow water. I couldn't get my camera to focus well on them past the surface of the water, but here's one of them:

These were the males, all defending small territories above the gravelly bottom where they occasionally mated with less colorful females. They chased away other males and smaller fish who were trying to eat their recently fertilized eggs. Here's an iPhone video showing some of this behavior:

I'm still waiting for confirmation from more knowledgable folks than myself, but I'm pretty sure these were Sheepshead Minnows, a species associated with brackish water along the gulf and atlantic coast. What are they doing here?

There was a larger fish species, about six inches long, in the deeper water. My current best guess is that these were Gulf Killifish, another coastal species. Here's one of them:

One of the last animals I spotted was a small black dragonfly. I vaguely remembered that my Texas Dragonflies field guide showed some inland populations of Seaside Dragonlets, and I was pretty sure that's what this was. Seaside Dragonlets are usually very common on the coast and they are the only north American species of dragonfly that can reproduce in salt water. Here's the one I found:

So what are these coastal species that like brackish and salt water doing way out here on the Pecos river in west Texas?

This morning back in Austin I had the annoying and expensive chore of having to buy new car tires. I was waiting in line at Discount Tire and started chatting with they guy in front of me who turned out to be a geologist specializing in Texas ground water consulting (Allan Standen). While we were waiting for our cars at at a nearby coffee shop, I told him about my recent observations on the Pecos River near Iraan. He told me that back in the 1940s, just north of Iraan was an important area for oil production during World War II. Deep salty ground water was pumped up to flush oil reservoirs, and probably made the surface water brackish in that area to this day. (He's a remarkable guy, and has some amazing visualizations of aquifer levels here.) That explains why these coastal species like it out there on the Pecos.

My field guide for fresh water fishes in Texas shows Sheepshead Minnows and Gulf Killifish both occurring in this area and says their presence here is because of deliberate introduction. But I wonder how the Seaside Dragonlets and Marl Pennants got there.

There were a few more odonates I photographed and I got some great photos of a Swainson's Hawk soaring overhead. See that attached observations.

And here are the same photos on Flickr.