Pedernales Falls State Park Prothonotary Warbler Nest Box Study: Acadian Flycatchers & Coral Snake

Prothonotary Warbler Occurrence In Texas

Central Texas draws the western line for the Prothonotary Warbler range. This species occupies much of eastern North America up to the southern boarder of Ontario Canada.
Prothonotarys' nest in natural cavities but also readily use nest boxes located on or near water. Flooded swamps represent ideal habitat but they will also nest along rivers or small bodies of water.
In May 2007 I saw a brightly colored male Prothonotary Warbler at Pedernales Falls State Park bird blind. After some research I learned male birds have been seen building nests in neighboring counties to Blanco County. Further research revealed a pair of Prothonotary Warblers successfully nested at Heard Wildlife Sanctuary in McKinney, Texas.
In December 2007 I decided to undertake a nest box study at the park. January through February 2008 I hiked the entire Pedernales River and tributaries within park boundaries, in an effort to choose the best sites. Habitat selection proved a challenge do to high flood levels along the river.
Five sights were eventually selected where two nest boxes each were placed. Most boxes were attached to trees however two were attached to metal poles. These boxes were monitored from March through June 2008 on a weekly basis. A Breeding Bird Study was conducted at each nestbox location in 2008 and will be continued in 2009.

Saturday, June 7, 2008

Acadian Flycatchers & Coral Snake

Overcast skies made today's survey more bearable. As summer settles in it appears the Acadian Flycatchers decided to move in as well. What I thought was one male on territory at Tobacco Creek turned out to be two, one at Tobacco Creek and the other at the Seep. I discovered an Acadian Flycatcher nest 25 feet up in a mature Hackberry tree along the Tobacco Creek ravine. It appears to be made of fine roots and is easy to mistake for a ball of moss hanging on tree branches. I saw the male feed one, almost grown, nestling. At East Park Boundary I found another male Acadian singing for the first time there.

On my hike into East Park Boundary I startled a Coral Snake along the side of the path. I watched it slither under a rock. The Coral Snake is very colorful and shiny. This is the second venomous snake I have found at Pedernales Falls State Park, the first being a Western Cottonmouth. I have yet to see a Rattle Snake here. At the mouth of Twin Falls Creek I took this photo of the Blue Grosbeak nest. The smaller speckled egg was laid by a Brown-headed Cowbird, a brood parasite.

Today I wrote up my notes at Pedernales Falls parking lot. There I watched fledged Cliff Swallows perch on a utility line. I also discovered a Lark Sparrow nest in the lowest most branch of a juniper tree near the restrooms. The parents did not tarry at the nest when delivering food. I do not know whether this behavior is normal or because of frequent human disturbance.

The photo above is a bat I found laying dead on the trail to Twin Falls. I guess this bat to be the Mexican Free-tail. One final note, I heard several Rufous-crowned Sparrows singing along the Wolf Mountain Trail. It appears these fellows enjoy the start of summer also.