Bell's Vireo & Brown-headed Cowbird Egg

After verifying which egg was the Brown-headed Cowbird's I returned today to remove it from the Blue Grosbeak's nest. The cowbird's egg, pictured here, has speckling on it, and lucky for me the grosbeak's eggs are pale blue/white, an easy distinction in this case. Cowbird nestlings typically out-compete their smaller nest mates for food. This species has increased it's numbers in North America thanks to forest clearing creating more edge for it to search out host nests. So wherever there are threatened species nesting, cowbirds are being actively trapped and nests monitored to remove these eggs.

I started out this morning at the Bird Blind where I saw all the usual nesters, however, in the scrubby patch of land adjacent to the trail I heard a Bell's Vireo. Its song matched my recordings, very fast and bubbly like a House Wren. Later two Bell's Vireos came to the oak tree along the open edge of the bird blind. This is a new species for me in the park. It likes shrublands that include willows and streamsides.

I also verified that the Lark Sparrows are tending young in the nest. Viewing the nest from below, it is rather camouflaged to the human eye.

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.

Lazy Summer Day & Breeding Birds

Six A.M. 67 degrees with overcast skies as I biked to East Park Boundary. I wish I camped overnight as it would have been perfect sleeping weather out here. The Common Nighthawks were doing their display dive.
Though many birds have fledged young, like the year round residents, there are a fair number of late migrants who are still on eggs or feeding nestlings at this time. I saw a Summer Tanager Thursday carry a large white grub away to the nest. Today I saw a female Golden-cheeked Warbler eating insects rather urgently. I believe she left the nest with eggs to fuel herself.
There are three vireo species nesting along the river: the White-eyed Vireo, Yellow-throated Vireo, and Red-eyed Vireo. The White-eyed Vireo arrived a couple weeks earlier than the other two species so one can see and hear many family groups moving around. The Yellow-throated Vireo really likes to hang out in the Bald Cypress trees along the river. Painted Bunting males on territory can be heard just about everywhere in the park, and Indigo Buntings can be found in lesser numbers along the river. The Blue Grosbeak female was adding her finishing touches to the nest I found on Thursday.
The Acadian Flycatcher finally made its appearance to the Tobacco Creek Seep half way through my survey there. It sang and made a twittering sound while flicking its wings. I believe this male has a mate sitting on eggs somewhere. This individual has been sited here the entire month of May.
The flower photo is the Twisted Leaf Yucca which is blooming abundantly throughout the Hill Country right now. I added the second Yucca photo to show when the blooms fall off of the tall flowering stalk they get impaled on the pointed leaves below. At the end of every survey I settle down to writeup my field notes. When my last site is Hackenburg Creek I take advantage of the Bald Cypress shade along the river.

Nesting Blue Grosbeaks & Nest Box Updates

Today was a treat being out at the park surveying breeding birds during the week. The campground and trails were quite peaceful with few visitors. Once again I had Common Nighthawks active through mid morning. The highlight was finding a pair of Blue Grosbeaks building a nest near the Pedernales River and Twin Falls Creek. This male is a first year bird with only a blue head.
I found the Rufous-crowned Sparrow for the second week in a row along Wolf Mountain Trail at the location pictured with my mountain bike. This sparrow has a beautiful song. The flowering Yucca is a Twisted leaf Yucca in bloom and visible along many roads in the Texas hill country.
Today I opened each nest box to see what critters were occupying them. They almost all turned out to be in the Insect order, other than one Arachnid.
A wasp species was found in six nest boxes, three boxes were entirely empty, three had the Organ-Pipe Mud Dauber Wasp, and one had Cock Roaches. The Mud Dauber is docile. It paralyzes a spider, places it in a vertical mud cylinder, then lays an egg never to return to the nest.
The Acadian Flycatcher is still present at Tobacco Creek. There are four species of warbler nesting along the river at nest box sites, the Louisiana Waterthrush, Black & White Warbler, Northern Parula, and Golden-cheeked Warbler. Water levels in the Pedernales River continue to drop from lack of rain. I snapped this photo, a tranquil river scene from East Park Boundary.

Tobacco Creek Seep

Summer heat and lack of rain have lowered the water levels in the Pedernales River. Bee Creek crossing on Wolf Mountain Trail usually has water but for the first time this year it is dry.
I arrived at Hackenburg Creek by 6:20 AM. Only four bird species were singing. By 8 AM I arrived at the Tobacco Creek Seep nest box 5. In the bird world this is the corner station, only instead of gasoline, water is being served. I saw the following families: White-eyed Vireo, Northern Cardinal, Carolina Wren, Carolina Chickadee, and the Louisiana Waterthrush (2 adults and 1 fledgling) come for drinks. I also saw a beautiful male Golden-cheeked Warbler come down to bathe.
I was also greeted by a male Acadian Flycatcher singing loudly: PEET-ssah. This species hawks insects from the middle canopy so seeing it on territory is relatively easy. I was surprised to hear a Great-crested Flycatcher at site 6. On my bikeride today I stopped to identify, visual and audio, a Rufous-crowned Sparrow. At East Park Boundary I had a fledgling Louisiana Waterthrush approach within 20 feet of me. It was rather curious. The Green Kingfisher gave me a fleeting glance as it bolted upstream. I also saw an Orchard Oriole singing atop a cypress tree along the Pedernales River and a new born fawn could be heard crying for its mother across the river.
At my final nest box site #4, I saw a male and female Blue Grosbeak. This guy was a first year male with blue mostly confined to its head. To finish the day I cooled off in the Pedernales River like many other people did.
On my hikes today I noticed a new creature to contend with, this huge spider who spins its web across trails. Lucky for me I have a birder's eye.