Pedernales Falls State Park Prothonotary Warbler Nest Box Study: Summer Bird Songs Waning

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 28, 2008

Summer Bird Songs Waning

My experience with Breeding Bird Censuses are most birds are identified by song. However, as the breeding season progresses I am detecting more birds by visual ID. Today that threshold has been reached. There really were not a lot of birds singing, a product of fledged young and moving family units. White-eyed Vireos continue to be vocal along with a few Painted & Indigo Buntings. Golden-cheeked Warblers have been quiet for two weeks now, yet I still see individuals at Twin Falls.

I did hear for the first time on this survey an Eastern Wood Pewee singing at Tobacco Creek and another bird sited at East Park Boundary. The Acadian Flycatcher nest #2 at Tobacco Creek Seep was still active with a female

flying onto the nest as I arrived. By now this bird should have young. The Blue Grosbeak nest at the Twin Falls and Pedernales River location has two 14 day old young in the nest. Photo above right. Both parents were actively feeding them. One Rufous-crowned Sparrow continues to sing at Twin Falls.

I walked upon a Rock Squirrel, near Tobacco Creek. It was in no hurry to hide so I was able to take some photos of it resting on a rock and taking a dust bath. Looks like I have one more week of surveying to follow-up on the two active nests. I hope to be back the Fourth of July.