Insect Oasis

Portrait of a Hermit Thrush on the beach at Galveston, Texas
This Hermit Thrush emerged from a patch of cane along the eastern tip of Galveston Island.

I was a bit surprised to see this Hermit Thrush hop out of the cane patch I was hiding in last weekend on the east end of Galveston Island. I’ve only seen Hermit Thrushes in their typical habitat—the understory of coniferous or deciduous forests. Instead of rummaging through moist leaf litter, this little one hunted a sea of sand punctuated by 12-foot-tall bamboo stalks. Was it lost?  I don’t think so. . . . It was keeping good company. In the course of less than an hour, I observed an Eastern Phoebe and a Ruby-crowned Kinglet find a variety of tasty insects and spiders. Also, just the week before, I spotted a Swamp Sparrow and a female Indigo Bunting and Redstart in the same small patch. Hmmmmmm.

Ruby-crowned Kinglet hunting at Galveston Island, Texas
I observed this Ruby-crowned Kinglet fishing spiders out of nooks and crannies.
Eastern Phoebe perched on giant river cane on Galveston Island, Texas
I spotted this Eastern Phoebe using cane as a hunting perch.













Questioning how this cane patch could be an insect-rich oasis for migrating and wintering birds led to a little research project (as do many of our outings). I had always assumed these patches of cane scattered on the beach and coastal waterways were foreign and invasive. Since non-natives don’t typically support complex ecosystems, I initially turned my nose up at them. (Invasive plant species often provide cover and water but do not support a wide diversity of prey species required for a complex food web.) As it turns out, Arundinaria, our only native bamboo, is endemic to the eastern half of the US.

With newfound respect, I look forward to a much more enlightened investigation of these remnant coastal bamboo “forests.” If you decide to venture into the cane, don’t forget your snake boots!

© 2012 Elisa D. Lewis. All rights reserved. No text or images may be duplicated or distributed without permission.

New Article: The View from the Park Blind

Many parks and wildlife refuges include photography and observation blinds. These can provide some excellent opportunities. In The View from the Park Blind, I consider some of the pros and cons of these structures and the associated feeding stations.

Spotted Towhee at Franklin Mountains State Park, West Texas
Spotted Towhee at Franklin Mountains State Park, West Texas. The excellent blind at this park allows the visitor to easily observe many desert-loving species of birds and mammals.

© 2012 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

New Article: Perspective in Nature Photography

Photography is the art of compromise: shutter speed versus aperture (and depth of field), ISO versus noise, versatility (zoom) versus sharpness (prime), and so on. In nature photography, obstructions often give the shooter little choice about tripod and camera position. When choices are available, other compromises come into play. Namely, tripod height affects not only an animal’s appearance in profile and the look of the environment, but also photographer reaction time. In Perspective in Nature Photography I explore these issues.

Broad-winged Hawk in tree, Houston, Texas
No choice: Broad-winged Rodent-hunter in Dense Forest. This Broad-winged Hawk was perched at a height of about ten feet in a dense patch of woods. This shot was literally the only one available, taken through a foot-wide opening in the foliage. After watching me drag my tripod and 500mm f/4L in a semi-circle through a tangle of brush for ten minutes trying to get a better perspective, the bird became annoyed and flew off.

Fall and Winter Fruits . . . Ah, the Irony. . . .

Knowledge is knowing that a tomato is a fruit. Wisdom is knowing not to put it in a fruit salad. –Brian O’Driscoll

One of the treats of birding in the cooler months is watching for birds enjoying the many types of conspicuous fruits and berries that can be found in the woodland habitats of the Texas Gulf Coast. Yaupon holly (Ilex vomitoria), greenbriar, and agarita are just a few of the many examples of native plants bearing brightly-colored berries during fall and winter that are popular with birds. As a photographer I always have an eye out for a Cedar Waxwing, American Robin, Northern Mockingbird, or Northern Cardinal with a rosy-ripe and juicy berry in its beak.

As a novice field botanist, I often photograph newly encountered fruit-bearing plants with the hopes of later identifying them. It soon becomes evident, however, that the landscape is dotted with exotic fruit-bearing plants from around the globe–escapees from gardens, seeds sown through the digestive tracts of birds or mammals. Sometimes they are identifiable, sometimes not.  I’m sure some of the species that I find impossible to identify are, to landscapers and nurserymen, commonly-known, popular garden varieties–from South America, the Caribbean, or that great cradle of Angiosperm evolution, Northern China.

A House Finch Eats Chinese Tallow Fruit. Federal biologists imported Chinese tallow into the U.S. in 1905. This plant is now taking over many forests of the South. Photo taken in Houston, Texas. Canon EOS 7D/500mm f/4L IS (+1.4x TC).

It might be tempting to suppose that these introduced species may be harmless or even helpful to birds, given that they produce edible fruits. Species of Pyracantha, for example, are commonly encountered invasives that produce copious amounts of bird-friendly fruit–and birds are implicated in the spread of these Eurasian plants. The Chinese tallow tree is another common invasive. Chinese tallow may be the greatest challenge, after man himself, to the warm native forests of North America. About 23% of all trees in the Houston area are now Chinese tallows.

In contrast to many of the natives, some of these foreign plants seem strangely sterile: not an arthropod of any kind is to be seen on them. As these foreign invaders have proliferated, robbing pollinators and insectivorous birds, displacing and replacing native ecological equivalents, songbird numbers have declined an estimated 40% in my lifetime. Of course, it’s hard to prove which aspect of humankind’s activities–chopping, plowing, spraying, shooting, paving, or planting foreign invasives has been most disastrous for our birds–but to me it doesn’t really matter–it’s all of a piece. Homo sapiens sapiens, the Yersinia pestis, of the planet’s biosphere marches unrelentingly on  . . . We are, it seems, in the midst of an anthropogenic mass extinction event. And the Dodo, Ivory-billed Woodpecker, Passenger Pigeon, Carolina Parakeet and Hawai’i Mamo bore witness. . . .

Pyracantha sp,, in Houston, Texas
Pyracantha, a Eurasian invasive, is displacing native plants. The brightly-colored berries are attractive to birds that disperse the seeds. Photo taken in Houston, Texas. High-speed synchronized flash.

©2012 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Conspicuous Consumption?

Black and yellow garden spider with grasshopper
This female Argiope aurantia (aka, the black and yellow garden spider or writing spider) easily subdues a grasshopper that launched itself into her web after an unlucky jump.

While most visitors to Brazos Bend State Park keep an eye trained on the water for alligators, I seek the park’s lesser championed predators suspended in plain sight along swampy summer paths. But it wasn’t until I spotted this Argiope tending to her prey late last month that I realized we had missed the usual spider-o-rama fest that normally occurs late each summer and early fall – or did it miss us? A conversation with one of the park’s excellent naturalists confirmed that this has been a bad year for the conspicuous black and yellow spiders that typically drape the pathways with their giant webs. Two species’ females with this general description are readily observed–Argiope aurantia pictured above, and Nephila clavipes the golden silk orb weaver or banana spider, shown below.

The golden silk spider is known for its gold-colored silk that the female spins into webs reaching up to 3 feet in diameter. Visitors to Brazos Bend State Park can typically see large concentrations of these spiders along paths bordering swamps from late summer to early fall.

Why would spider populations plummet in one year’s time?

Could it be that last year’s drought put these spiders (most likely prey of last resort given their warning coloration and the danger of entanglement) in the precarious position of being the most conspicuous food source around for hungry, desperate birds? Perhaps the effect was compounded by a collapse of the arthropod food web?

In any case, we’ll be watching spider populations next season.

New Article: Birding the Four Seasons

As a birder it seems that there is always something to look forward to–and not just the work-a-day longings for the next weekend or vacation. The precession of the equinoxes now deeply affect what I see and do. Like some pagan Celt or a boy waiting for the thaw, I connect with the seasons, how the tilted planet travels around the sun, and the flow of energy across the solar system and into the biosphere . . .

Male Pileated Woodpecker in nest cavity at Brazos Bend State Park, Texas
Male Pileated Woodpecker in nest cavity at Brazos Bend State Park, Texas. Woodpeckers in nest cavities are one of the real treats of spring. Sadly, this dead old tree, simultaneously home to at least three woodpecker nests (Downy, Red-bellied, and Pileated) fell over this spring.

Last Brood of the Moorhens?

Common Moorhens may raise up to three broods per breeding season, especially in their southern range, but I was a bit surprised to find a pair of Moorhens with young chicks on the autumnal equinox, September 22, 2012. It got me thinking that these chicks, seen near the end of September, are most likely the last brood of the season at Brazos Bend State Park, Texas. Day-length, or photoperiod, along with temperature changes, govern many seasonal changes in animals including changes in the coloration of fur/feathers, hibernation, migration, and mating behavior. Here, along the gulf coast, our seasonal changes are gradual – permitting longer growing seasons and, happily, longer baby bird watching as well!

Common Moorhen with chick exhibiting begging behavior.
With their bald patches and what look like bad hair-plugs, Common Moorhen chicks could easily win a “so-ugly-they’re-cute” contest. This little one is begging for food by “flapping” its stubby wings.  Moorhens with young can be found throughout the long, hot summer at Brazos Bend State Park, Texas.

See Early Fall Migrants on the Texas Gulf Coast (and don’t forget your sunscreen and bug repellent)!

Elisa and I have been out trying to catch glimpses of the early fall migrants, especially songbirds, along the Texas Gulf Coast at places like Sabine Woods, Brazos Bend State Park, and Anahuac National Wildlife Refuge (ANWR) . . . and we have been paying the price. Until the first real norther arrives, the heat, humidity, and bugs rule. It makes sense that the larger the number of insects, the larger the number of migratory insectivorous songbirds that one would find at any given locale along the Texas Gulf Coast. This is the general pattern that we have observed: Brazos Bend is generally the least buggy (almost anomalously so) of any of the major birding spots we frequent, and we see the fewest insectivorous songbirds there. Of course, Brazos Bend is farther from the coast than the other localities, so it not a migrant trap. But Brazos Bend has so few flying insects, biting and otherwise, that it has caused me speculate about the cause(s). There is plenty of standing water for mosquito reproduction, but there are also large numbers of deer in the park, and large ungulate populations have been shown to negatively impact songbird populations due to grazing on insect and bird food plants (reference Aldo Leopold). On the other hand, the bugs at Sabine Woods and ANWR can be brutal. Today at ANWR (Skillern Tract) the deer flies and mosquitos literally chased us out of the marsh! Bugs are food for birds and food for thought.

Black-throated Green Warbler portrait at Anahuac National Wildlife Refuge, Texas
Black-throated Green Warbler on Hackberry Branch. Note the insect body parts on the tip of the beak. I think I was being eaten alive by the very bugs this beauty was dining upon. Skillern Tract, ANWR, Texas Gulf Coast.


Yellow Warbler on Oak branch at Sabine Woods, Texas
A Young Yellow Warbler perches on an oak branch at Sabine Woods, Texas Gulf Coast. A glimpse of paradise in a sweltering purgatory of biting insect nasties.

New Additions to Collections

Although being in the field regularly is always preferable, bad weather and the threat of bad weather have kept me indoors of late. Birding time has been transformed into computer time: additional images have been added to the Stalking the Hunters: Additional ImagesTexas Ducks, and Galveston Island Birds collections. Expect more in the near future.

Loggerhead Shrike with snake at Brazos Bend State Park, Texas.
This Loggerhead Shrike has just seized a snake. Shrike numbers increase significantly during the cooler months at Brazos Bend State Park. Shrikes, like other birds with black masks are challenging to photograph: the light has to be just right to capture a catchlight and a well-defined eyeball. Photo taken near water’s edge, Pilant lake.
Thermoregulating Great Blue Heron at Brazos Bend State Park, Texas
Thermoregulating Great Blue Heron? at Brazos Bend State Park, Texas. Herons and egrets can be seen occasionally in this sort of pose on hot, sunny days. It has been speculated that this is related to thermoregulation, but to my knowledge the details remain obscure. On the sweltering days when I see this sort of behavior, it would seem that warming up in the sun would be the last thing a bird would want to do–unless they are sterilizing parasites or pathogens thermally while employing gular fluttering or “panting” to keep their brains from frying. Photo taken at Pilant Lake.

 © 2012 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Texas Ducks: A New Collection

Because of the abundance and diversity of wetland habitats along the Texas Gulf Coast, ducks are an important part of the Texas avifauna–and they remain one of my favorite photographic subjects. Without fail, when I present slide shows of images to friends and family, the ducklings are the most popular and collect the most “ooh’s and ahh’s.” Let’s face it: ducks and ducklings are fun.

Muscovy Ducklings at Hermann Park, Houston, Texas
Muscovy Ducklings at Hermann Park, Houston, Texas. Remarkably, no matter how different the adults look (and Muscovy Ducks are among the weirdest-looking of all ducks), many ducklings look alike-yellow with black stripes. Somehow that doesn’t affect their popularity! Canon EOS 7D/100-400mm f/4.5-5.6L IS. Natural light.

©2012 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Fly vs. Fly

When the sun is high in the sky and the light isn’t conducive for bird photography, I like to bust out the macro lens and look for smaller wonders. I found this robber fly taking a break among the scrubby beach vegetation while its neurotoxic, proteolytic saliva paralyzes and chemically digests the insides of its current victim. Charming. It’s a good thing (for us) that these flying assassins exclusively prey upon arthropods – mostly other insects at that.

Robber fly predator with fly prey
Robber flies frequently make meals of other flies. Galveston Island (East End), Big Reef Nature Park, Texas


Instinctive Behavior in a Green Heron, Brazos Bend State Park, Texas

What a book a devil’s chaplain might write on the clumsy, wasteful, blundering, low, and horribly cruel work of nature! –Charles Darwin

Usually when one sees a wader grab a prey item, the prey is subdued, perhaps by a few pecks, then manipulated into position and swallowed. Today at Brazos Bend State Park, however, I observed a Green Heron grab a large American Bullfrog tadpole. The bird picked up and then dropped the tadpole a few times after intermittently pecking it. Finally the bird discarded the tadpole and walked away. I thought this strange given that waders of all species at Brazos Bend eagerly consume amphibians in all stages of development. Perhaps (although it seemed unlikely) the bird considered the tadpole to be too big to swallow?

I continued to watch the Green Heron fully expecting the bird to reconsider and return to the tadpole and eat it. Instead, it caught a juvenile frog and repeated the whole process! After pecking the poor frog a few times, the Green Heron just walked off without eating it. I have only seen this sort of thing once before when a Little Blue Heron captured and then discarded a crawfish. Do these waders hunt and kill (or at least maim) instinctively without being hungry, and without lardering the prey–just like well-fed house cats? If so, stone cold killers, these fellows!

Green Heron with juvenile frog at Brazos Bend State Park, Texas
Bad Day at Elm Lake: this Green Heron captured, subdued, beaked, and then discarded without eating this unfortunate frog. Canon EOS 7D/500mm f/4L IS (+1.4x TC). High-speed synchronized fill-flash.

©2012 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.