Brazos Bend

Experiments in Dragonfly Photography

Flame Skimmer Dragonfly at Lost Maples State Natural Area, Central Texas
Flame Skimmer Dragonfly (Libellula saturata) at Lost Maples State Natural Area, Central Texas. Elisa got this shot with a Canon EOS 7D/300mm f/4L IS (+1.4x TC)/tripod. According to internet sources, the 300mm f/4 is a popular lens for dragonfly shots. Natural light.

During the summer in Gulf Coast Texas, when bird diversity is relatively low, there are generally lots of insects–especially dragonflies–to draw the photographer’s attention. Clearly dragonflies, although small, cannot be treated like typical macro subjects, at least most of the time. First of all, they are highly aware of their surroundings and sometimes won’t let you get close to them. Second, along the Gulf Coast they are often perched on emergent vegetation in alligator- and water moccasin-infested water, or chigger-infested grass.

Mating Halloween Pennant Dragonflies in strong breeze, Brazos Bend State Park, Texas
Mating Halloween Pennant Dragonflies (Celithemis eponina) in a Strong Breeze at Brazos Bend State Park, Texas. Photo taken at Elm Lake. This shot was only cropped significantly in the horizontal dimension: In other words, these insects nearly filled the frame vertically with this combination of equipment at the minimum focus distance. Canon EOS 7D/600mm f/4L IS (+1.4x TC)/tripod with high-speed synchronized flash.

So rather than use a lens requiring a close approach (the super sharp 100mm f/2.8L IS macro, for example), the question becomes which super telephoto is the best dragonfly lens? Further, is flash necessary or even best? Should the 1.4x teleconverter be used? What about extension tubes? With this many questions and permutations of possible combinations of equipment (plus field considerations), I’ve come nowhere near a definite conclusion, but at least I have identified some issues–and I’m excited about further experimentation!

Although I know that some photographers use extension tubes in this application, for the moment I’m taking them off the table primarily because these devices (hollow tubes inserted between the camera and lens that decrease the minimum focus distance while retaining most camera functions) significantly decrease the flexibility of the set-up. Extension tubes cost image brightness, slow autofocus (if they allow it to function at all), slightly shift the focal point of the lens, and degrade the ability to focus at a distance. I’m looking for a rig that will allow excellent captures of dragonflies while preserving my options should a bird or other animal suddenly appear at a larger distance.

That said, the different super telephotos I have access to (100-400mm, 300mm, 500mm; 600mm) have different minimum focus distances (MFD) and magnifications. Of these, the 100-400mm is definitely out: It is a versatile lens, but it just isn’t as sharp as the primes (fixed focal length lenses). The 300mm has the closest MFD (4.93 ft), but in my experience that is often irrelevant because the bug won’t let you get anywhere near that close.

On the other end of the scale, dragonflies will almost always let you get to the MFD for the 600mm (18.04 ft), but that’s pretty far away for such a small animal. Teleconverters do not affect MFD, but they soak up a little light and degrade sharpness (only slightly for 1.4x on a prime). So far, I have liked some shots taken with the 600mm (+1.4x TC). This is probably because of the number of opportunities I’ve been able to take with such a large MFD–I don’t risk trying to get too close and chase the subject away.

Female Four-spotted Pennant Dragonfly at Brazos Bend State Park, Texas.
Female Four-spotted Pennant Dragonfly (Brachymesia gravida) at Brazos Bend State Park, Texas. Canon EOS 7D/600mm f/4L IS/tripod. High-speed synchronized flash.

Of the three primes (with teleconverters attached) being discussed here, the 600mm should give the worst results on theoretical grounds. The ratio of focal length (the longer, the better) to MFD (the smaller, the better), is a way to think about this issue. The larger this ratio, the better because it expresses how much focal length “firepower” you have per separation distance. For the 300mm (+1.4x TC), the focal length/MFD ratio = 85 mm/ft. For the 600mm (+1.4x TC), focal length/MFD ratio = 47 mm/ft. The ratio for the 500mm has a value of 48 mm/ft, nearly the same as the 600mm. So if you could get close, the 300mm should be best–but often you can’t get that close. Compromise strikes again!

As far as flash is concerned, it seems to be primarily a matter of taste. Natural light, of course, looks more natural. The flash reveals fine details, especially in the shadows, sometimes not visible in natural light. Flash can sometimes create a magical, almost surreal effect as in the case of the Halloween Pennants above. One clear problem with the flash is the same as in the case of birds: the flash adds an extra catchlight in the eyes. Because dragonflies have large compound eyes, the effect can be pronounced.

Swift Long-winged Skimmer Dragonfly at Elm Lake, Brazos Bend State park, Texas
Swift Long-winged Skimmer Dragonfly (Pachydiplax longipennis) at Elm Lake, Brazos Bend State park, Texas.
Canon EOS 7D/600mm f/4L IS/tripod. Natural light.

So . . . what to do? For now, keep working, trying new combinations, and see if a clear choice emerges that preserves options and image quality. Finally, all this thought about dragonflies has clearly benefitted my bird photography in one way. I can now easily recognize all the common dragonflies around the places I normally shoot, and thus can put a technical name on some of the meals my beloved waders are enjoying!

Green Heron with Green Clearwing at Brazos Bend State Park, Texas
Green Heron with Green Clearwing (Erythemis simplicicollis) at Brazos Bend State Park, Texas. This is my favorite type of dragonfly photography. Canon EOS 7D/500mm f/4L IS (+1.4x TC)/tripod. Natural light.

“Your first 10,000 photographs are your worst.” ― Henri Cartier-Bresson

©2013 Christopher R. Cunningham and Elisa D. Lewis. All rights reserved. No text or images may be duplicated or distributed without permission.

A Diversity of Menu Items for Waders at Brazos Bend State Park, Texas

Green Heron with Fishing Spider at Brazos Bend State Park, Texas.
Green Heron with Six-spotted Fishing Spider (Dolomedes triton) at Brazos Bend State Park. Photo taken near Pilant Slough. Canon EOS 7D/600mm f/4L IS (+1.4x TC). High-speed synchronized flash.

There has been a bumper crop of fishing spiders this year at Brazos Bend State Park, and I have seen Little Blue Herons and Green Herons eat them, sometimes one spider right after another. Some years it seems as though wader diets consist of a fairly uniform mix of aquatic vertebrates and invertebrates, especially crawfish. This year, rather than crawfish, waders seem to be relying more heavily on smaller invertebrate prey items than in recent years. Lots of aquatic insect larvae, dragonflies, adult aquatic bugs and beetles, and spiders are being consumed along with the occasional small fish, frog, or tadpole.

Little Blue Heron with Dragonfly
Juvenile Little Blue Heron with Swift Long-winged Skimmer Dragonfly (Pachydiplax longipennis) at 40-Acre Lake, Brazos Bend State Park, Texas. Juvenile Little Blue Herons are fun to stalk: they are prolific hunters but, being young, they still have a level of naiveté toward humans allowing a close approach. Canon EOS 7D/600mm f/4L IS. High-speed synchronized fill-flash.

Invertebrates are highly sensitive to environmental conditions of temperature, humidity, and rainfall. This year’s unusually cool, dry spring may have led to a different mix of potential prey for waders. The Upper Texas Gulf Coast is already behind in rainfall for the summer and water levels already appear low, perhaps impacting aquatic vertebrate numbers as well.

Many of the invertebrates (spiders especially) I see waders take are living among the Water Hyacinth that is growing profusely in some areas of the park. Water Hyacinth is native to the Amazon Basin, but has been imported to many areas of the world where it has become a major nuisance by crowding out and shading native plants and choking waterways.

Water Hyacinth at Brazos Bend State Park, Texas
Beautiful Invasive: Common Water Hyacinth (Eichhornia crassipes) at Brazos Bend State Park. Water Hyacinth is costly and troublesome for land managers. Mechanical, chemical, and biological mechanisms for its control have been devised and employed worldwide.

Besides keeping an eye (and a lens) out for interesting wader predator-prey relationships, I am always on the look-out for hunting techniques. For example, Snowy Egrets are known for shuffling their bright yellow feet in the shallows to flush out prey. Several times over the past weeks I have seen a Snowy Egret (I think it was the same bird) employing a bubble-blowing technique on Elm Lake. This bird was (presumably) blowing bubbles to attract prey. Perhaps the bubbling simulates a small struggling animal, attractive to fish and other aquatic predators. Between bouts of bubbling, this bird also opened and closed its beak, a fishing technique I have seen employed by Black-crowned Night-Herons and Great Egrets, and one that also sends ripples out into the water. One time during this process this Snowy Egret grabbed a small aquatic invertebrate–it was down the hatch too fast to tell for sure what it was, although it was about the right size and shape for a water tiger (larval predaceous diving beetle). On another occasion, the egret was clearly catching small fish with this technique. Time will tell if anything bigger can be attracted by blowing bubbles!

Snowy Egret blowing bubbles at Brazos Bend State Park, Texas
Snowy Egret Blowing Bubbles at Brazos Bend State Park, Texas. Photo taken at Elm Lake. Canon EOS 7D/600mm f/4L IS. High-speed synchronized flash.

©2013 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Summer Birding is Here: Young Water Birds Out and About at Brazos Bend State Park, Texas

Juvenile Wood Ducks at Brazos Bend State Park, Texas
Juvenile Wood Ducks at Brazos Bend State Park, Texas. Wood Ducks are tough to find at BBSP: They are typically suspicious of humans. These were young enough to retain their naiveté. Canon EOS 7D/600mm f/4L IS (+1.4x TC). Photo taken near Pilant Lake in late June. High-speed synchronized fill-flash.

After a really interesting spring migration, I have settled into summer birding along the Texas Gulf Coast. Although I occasionally run into hearty souls willing to brave the Texas heat to see and photograph their beloved birds, the birding crowds have thinned. On those particularly broiling summer days, it sometimes feels as though I have the whole park to myself.

Common Moorhen Chick at Brazos Bend State Park, Texas
Common Moorhen Chick at Brazos Bend State Park. Mom will spend much of the summer feeding this little guy aquatic insects. Baby Common Moorhens, with their black fuzzy feathers and propensity to stand in blazing sunlight, are difficult to photograph. Photo taken at Elm Lake. Canon EOS 7D/500mm f/4L IS (+1.4x TC). Natural light.

Although avian diversity is at its nadir at this time of year, certain things can only be seen in summer, and these make going out well worth the effort. These include Purple Gallinules, Common Moorhens, and Black-bellied Whistling-Ducks raising young. The latter are particularly fun to watch as parents coolly and calmly usher their ducklings into the marsh vegetation in the face of perceived threats.

Black-bellied Whistling-Ducklings at Elm Lake, Brazos Bend State Park, Texas.
Black-bellied Whistling-Ducklings at Elm Lake, Brazos Bend State Park. What is there to say, MP? Ducklings are cute. Canon EOS 7D/500mm f/4L IS (+1.4x TC). Natural light.

While the ducks and ducklings skulk off into the weeds when humans turn up, the Moorhens and Gallinules slowly stroll away from threats real and imagined on top of floating vegetation with babies in tow. Very young Moorhens and Purple Gallinules are fuzzy and black, little balls of darkness. Now and then, an alligator steams past and everyone keeps and eye out (including the photographer). A wader spears a frog. A Northern Parula sings, then a Prothonotary Warbler. And time passes slowly.

Young Purple Gallinule at Elm Lake, Brazos Bend State Park, Texas.
Young Purple Gallinule at Elm Lake, Brazos Bend State Park, Texas. This young Purple Gallinule has passed its black, “ball of darkness” phase. Canon EOS 7D/500mm f/4L IS (+1.4x TC). Natural light.

“Ah, summer, what power you have to make us suffer and like it.”–Russell Baker

 ©2013 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Canon 500mm f/4L IS USM versus 600mm f/4L IS USM: First Field Comparisons

Baby alligators on their mother's back at Brazos Bend State Park, Texas.
Baby Alligators on their Mother’s Back at Brazos Bend State Park, Texas. Photo taken near Pilant Lake. Canon EOS 7D/600mm f/4L IS USM with high-speed synchronized fill-flash at 1/640, ISO 640; f/13.

I feel incredibly lucky to have a wife who shares my passion for nature and bird photography: not only for companionship in the field, but for constructive criticism, technical help, and tolerance for acquisition of expensive pieces of equipment. One frustration of having a photographer partner, however, has been having to share the “big” lens.

Buying the 500mm f/4L IS two years ago was a life-altering experience for us. Before that, we had to share the 100-400mm f/4.5-5.6L IS: a nice lens, but nowhere in the same league as the 500mm in terms of autofocus speed, sharpness, image quality, and reach. With a 1.4x teleconverter (not to mention the 1.6x crop sensor EOS 7D) our new 500mm set-up really expanded our capabilities and started to land us some really nice results. No wonder this is such a popular combination of equipment among serious amateurs and professionals.

That said, the 500mm rig is heavy and awkward, especially with tripod, Wimberley gimbal, flash and “Better Beamer” flash extender attached. Lugging it through the brush can be exhausting, especially if there are low-hanging branches or tangled ground cover. It also attracts attention from the public who feel compelled to comment about the size of your “camera.”

To remedy the problem of having to share the 500mm, we recently acquired a used 600mm f/4 IS from B&H in New York. My first impression is that the 600mm is heavy, heavy, heavy. In fairness, it is only about 3 pounds heavier than the 500mm, 11.8 versus 8.5 pounds–but heavy enough to cause the tripod legs (Gitzo GT3541XLS) to slip when only tightened to minimum non-slip tightness for the 500mm. The 600mm is also physically larger–I would say chunkier and more ungainly. The carbon-fiber hood is much larger (I worry how it will behave in a significant wind). If you are not in good shape, these differences are significant–especially after about a four-plus mile hike, which is our typical outing. Furthermore, because the 600mm calls for the P-50 Wimberley lens plate for the gimbal, rather than the smaller P-40, the 600mm is much harder to carry the way I carry the 500mm set-up, namely with the top of the tripod resting on my shoulder. The P-50 digs into my shoulder. If I slide the lens backwards, it feels quite off-balance. I soon discovered that a folded handkerchief under the shoulder of my shirt makes a world of difference. On the second trip I figured out a way to position the 600mm set-up on my shoulder (with handkerchief)  without causing pain–at least for about three hours.

White-faced Ibis in non-breeding colors at Brazos Bend State Park, Texas
White-faced Ibis in Non-breeding Colors at Brazos Bend State Park, Texas.  Canon EOS 7D/600mm f/4L IS USM (+1.4x TC) with high-speed synchronized fill-flash.

My first impression optically of the 600mm is that the extra 140mm of reach (with 1.4x TC) really tests your technique, especially when exhausted, a bit shaky, sweat is burning your eyes, and deer flies are chewing on your face. My sense is that the 600mm focuses slightly faster than our 500mm (which is odd given that the 600mm has bigger elements to move), but I don’t have actual measurements, it just feels like it is faster. The depth of field for the 600mm is noticeably less than the 500mm, which is expected as depth of field is a function of object distance, f-stop, and focal length. This generally means shooting at higher f-stops and slower shutter speeds. I am already automatically nudging up the f-stop on the 600mm above what I would shoot on the 500mm: f/7.1 versus f/6.3 for small, relatively close birds, for example.

In some places we shoot some birds that are quite tolerant of humans, Brazos Bend State Park, for example. Juvenile little Blue Herons and Ibises, when they are focused on tasty frogs and crawfish will essentially ignore humans. They rarely will approach closer than the minimum focus distance (MFD) for the 500mm (14.8 ft.), though. Not so the 600mm (18.0 ft.). On several occasions I found myself having to back up to keep these birds in focus. After shooting with the 500mm for about two years, I more or less automatically and subconsciously adjust the object distance to be outside the MFD. I’m sure with practice my brain will adjust to the 600mm.

As of this writing (after four one-half days in the field), I have not encountered a situation where the 600mm is superior to what the 500mm would have produced. That being said, I also haven’t yet encountered a situation where the 600mm would really be expected to shine: where the subject is about 5-15 feet beyond the ideal distance for the 500mm. The 600mm reminds that photography is all about trade-offs and compromises and diminishing returns. For an extra 100mm of reach there is a large financial cost as well as a physical one. My favorite summer subjects are hunting waders, and I really expect that throughout the next few months many opportunities will arise (such as hunting waders on the other side of a bayou) that will convince me of the correctness of acquiring a 600mm rather than another 500mm lens. Time will tell.

Yellow-crowned Night-Heron with crawfish at Brazos Bend Sate Park, Texas.
Yellow-crowned Night-Heron with Red Swamp Crawfish at Brazos Bend Sate Park, Texas. Photo taken at Elm Lake. Canon EOS 7D/500mm f/4L IS USM (+1.4x TC). Natural light.

©2013 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Nest Box 24

Male Wood Duck at Brazos Bend State Park, Texas
Male Wood Duck at Brazos Bend State Park. This Wood Duck and his mate were extremely wary of humans. Smart ducks! Photo taken in March with high-speed synchronized fill-flash.

“Hey, there’s a pair of Wood Ducks hanging out by Nest Box 24,” Chris says with a knowing smile as we meet on the path encircling Elm Lake. “Excellent!” I reply. It’s my turn with the 500mm, and a good opportunity to practice my sit-and-wait technique. Patience has paid off in the past – especially with flycatchers returning to perches. So, with images of Wood Ducks in my head, I hurry on down the trail–politely refusing several offers to trade cameras with my point-and-shoot counterparts.

Slowing my approach as I get closer, I collapse the tripod to sitting height, identify the best angle given the light, then slip in among the brush. I am confident that my camouflaged ninja birding skills will produce a pair of Wood Ducks.

Mated pair of Blue-winged Teal at Pliant Lake, Brazos Bend State Park, TX
A mated pair of Blue-winged Teal feed on duck weed at Pilant Lake, Brazos Bend State Park, TX. Canon EOS 7D/500 mm f/4L IS (+1.4 TC): f/7.1, ISO 500, 1/3200, -0.3 EV, high-speed synchronized fill-flash.

At least there’s a handsome mated pair of Blue-winged Teal to keep me company. I wait. No Wood Ducks. The teal come in closer. Well, I might as well shoot them while I’m here. Done. I wait. No Wood Ducks. Hmm, maybe the Wood Ducks are IN the box! I train the camera on the nest box hole. I guess some images of a nest box would be nice. Snap. Snap. OK. I wait. No Wood Ducks. Hey! A head popped out of the hole!

Fox Squirrel peeking out from a nest box at Brazos Bend State Park, TX
A Fox Squirrel peeks out from Nest Box 24 in Pilant Lake, Brazos Bend State Park, TX. Canon EOC 7D/500 mm f/4L IS (+1.4 TC): f/11, ISO 500, 1/320, -0.7 EV, high-speed synchronized fill-flash.

Really? A squirrel. Hmph!

Wait a minute. What’s a squirrel doing in there? Is it hunting for eggs? Hunting for chicks? (That little #*%@!) Could it be tending a nest of its own? A little bit of internet research indicates it could be any of the above. I will need to keep an eye out for this in the future. I love it when I learn something new. Don’t you?

©2013 Elisa D. Lewis and Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Spring Migration Has Begun: Early Migrants Have Arrived on the Upper Texas Gulf Coast! (Just in Time for Wildflowers)

Male Northern Parula at the Sabine Wood Sanctuary, Texas Gulf Coast
Male Northern Parula at Sabine Woods.

We spent Spring Break 2013 (March 9-17) visiting some of out favorite birding sites along the upper Texas Coast in search of early migrants, with mixed results. Places visited included Lafitte’s Cove, East Beach, Sabine Woods, Edith L. Moore, Anahuac National Wildlife Refuge (NWR), Brazos Bend State Park, and the Big Thicket National Preserve (Pitcher Plant Trail). The weather was spectacular–crisp and dry. Recent frosts, however, probably have diminished the diversity and abundance of wildflowers in some areas.

Leather flowers at Anahuac NWR (Skillern Tract)
Blue Jasmine (Clematis crispa) at Anahuac NWR (Skillern Tract). This elegant plant was one of the few wildflowers in bloom here.

The insect (i.e., food) supply varied dramatically by location. Brazos Bend, as is typical, had relatively few biting insects but had a lot of crane flies, which at this time of year seem to be a staple for insectivorous birds. I saw American Pipits and Myrtle Warblers feasting on them. Likewise at Lafitte’s Cove there were few biting insects, but abundant Black and White Warblers and Northern Parulas were also dining on crane flies. Also at Lafitte’s Cove we were treated to a shy mated pair of Mottled Ducks.  Anahuac NWR had far fewer biting insects than is usual–but also fewer birds. Sabine Woods was, as always, loaded with biting insects–mosquitos, gnats, and other flies. At Sabine Woods, Gray Catbirds, a Louisiana Waterthrush, Black and White Warblers, and Northern Parulas were about. I was disappointed not to see Hooded Warblers in the lantana thicket on the east side of the sanctuary given that I had just seen one among the cane on the east end of Galveston the day before (March 12).

American Pipit with crane fly at Brazos Bend State Park, Texas
American Pipit with Crane Fly at Brazos Bend State Park near 40-Acre Lake. Crane flies are a staple for insectivorous birds during cool late winter/early spring weather. Photo taken hand-held, Canon EOS 7D/500mm f/4L IS.

We erred in not calling ahead before visiting Big Thicket. A recent controlled burn had swept through the Pitcher Plant Trail, leaving the understory and ground cover (including the Pitchers!) ash–although some grasses were making a recovery. The whole area was dry, black and desolate. A few titmice could be heard singing, a few woodpeckers drumming, but that was about it.

Louisiana Iris at the Edith L. Moore Nature Sanctuary, Houston
Louisiana Iris (Iris sp.) at the Edith L. Moore Nature Sanctuary.

The last day of birding over spring break was Saturday, March 16. We spent almost the entire day at Brazos Bend State Park, where male Northern Parulas could be heard singing in the trees. Also on this day, male Ring-necked Ducks could finally be seen and photographed out in open water with their mates. Over the past few weeks they have only been visible hiding out in the shallows off the islands in Elm Lake. A mated pair of Wood Ducks has been hanging around one of the nest boxes on the trail between Elm and 40-Acre Lakes, but they have been very shy, swimming for cover any time someone approaches. I finally got a decent shot of the male. I will keep trying for a shot of the pair.

Black and White Warbler at Lafitte's Cove, Galveston Island, Texas
Black and White Warbler at Lafitte’s Cove, Galveston Island.

Within a few weeks or so the woods and thickets should be hopping with additional migrants . . . Palm Warblers, Hooded Warblers, Magnolia Warblers . . . and we can hardly wait!

Scarlet Buckeye at the Edith L. Moore Nature Sanctuary, Houston
Scarlet Buckeye (Aesculus pavia) at the Edith L. Moore Nature Sanctuary, Houston. One of the earliest splashes of native spring color in Gulf Coast woods.

 © 2013 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Additions to Collections: Texas Ducks and Galveston Island Birds

Over the past few weeks I’ve been slipping new images into the Texas Ducks and Galveston Island Birds Collections. Please take a look!

Female Ring-necked Duck at Brazos Bend Sate Park, Texas
Female Ring-necked Duck at Brazos Bend State Park. Ring-necked Ducks are generally not common at Brazos Bend State Park–except this year! Mated pairs could be seen feeding in the shallows off the islands in Elm Lake in February, but males would not venture into open water when humans were around. Photo taken at Elm Lake with high-speed synchronized fill flash and IS Mode 2.
Male Gadwall in flight over Elm Lake, Brazos Bend State Park, Texas
Male Gadwall in Flight over Elm Lake, Brazos Bend State Park.

© 2013 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.

Birding the Spectacular Thickets of the Texas Gulf Coast in Fall

Thicket at Anahuac NWR
A thicket at Anahuac National Wildlife Refuge (NWR), Texas Gulf Coast. This densely vegetated area was hopping with Yellow-rumped Warblers, Eastern Phoebes, and Swamp Sparrows.

Fall is an incredible time to bird the Texas Gulf Coast: migrants are returning or passing through, the plants are changing colors, mornings are cool, and the bugs are on the way out–but not all the way out, lest our beloved insect-eaters keep moving! Some of the most exciting environments to bird at this time of year are the densely-tangled thickets near the numerous waterways of the region. We especially love to bird Brazos Bend State Park, Sabine Woods, and Anahuac NWR (both the Skillern and Main tracts) at this time of year. Thickets in these areas are challenging for photography most of the year, but in fall are literally hopping in places with insectivorous birds.

Fall shedding of leaves leads to an opening up of possibilities for photography: the dense (often frustrating) greenery of summer, sometimes making it impossible to photograph shy, secretive thicket species is slowly breaking up. Splashes of color now punctuate images, and the amber and reddish glow of autumnal mornings and evenings tint backgrounds.

Common Yellowthroat at Pilant Lake, Brazos Bend State Park, Texas
Young Common Yellowthroat in Fall Morning Light. Photo taken at Pilant Lake, Brazos Bend State Park.

The explosion of insect-eaters during the fall migration is a reminder that the mass migrations of birds are all about the flow of solar energy. As the supply of warm-weather prey dwindles in the northern latitudes the bug-eaters must move south in search of their (mostly) ectothermic prey. The Texas Gulf Coast stays warm enough throughout the winter to keep a supply of insects large enough to support a large population of flycatchers, especially Eastern Phoebes, that can be seen perched on branches over water or open grassy areas. They flit down, grab an insect and then return to their perch to dine. A spectacular sight  to behold is a Phoebe grabbing a butterfly on the wing. Surprisingly, they ingest the whole insect, wings and all. One wonders how much nutritional value a butterfly wing has, though. Vermilion Flycatchers exhibit similar behavior in these thicket environments, but a discussion of these beautiful little birds must await Elisa’s next post!

Myrtle Warbler at Anahuac NWR, Texas
 Audubon’s Warbler Against Fall Colors at Anahuac NWR.  This locality is in East Texas, a place where one doesn’t normally see Audubon’s Warblers. Perhaps this bird is a Myrtle-Audubon’s hybrid? Shot hand-held Canon 7D EOS with 300mm f/4L IS (+1.4x TC).

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

Why Birders Should Care About the Global Amphibian Crisis

Little Blue Heron with tadpole at Brazos Bend State Park, Texas
Little Blue Heron with Tadpole at Brazos Bend State Park, Texas Gulf Coast.

Over the past several decades the diversity and abundance of Amphibia have declined precipitously: estimates for the amphibian extinction rate range from tens to tens of thousands of times the typical background rate of species loss. Despite conservation efforts (Amphibian Ark) and some publicity, most people I speak to are completely unaware of this catastrophic decline. Over the past decade or so, it has become clear that there are several major causes. The most important appears to be habitat loss. As freshwater swamps and marshes are drained to build the endless suburban sprawl of tract housing, and forests are bulldozed into the chippers, amphibian habitats are dwindling. Acidification of lakes and ponds, other forms of pollution, and an infectious fungal disease (chytridiomycosis), are also implicated.

American Bullfrog at Brazos Bend State Park, Texas
American Bullfrog (Rana catesbiana) at Brazos Bend State Park, Texas. American Bullfrogs are an abundant food source for waders along the Texas Gulf Coast. Luckily, bullfrogs appear to have resistance to chytridiomycosis.

Many think that the reason amphibians have been among the hardest hit groups in the current anthropogenic mass extinction event (the Holocene mass extinction) is because these animals have aquatic larval stages and a terrestrial or amphibious adult stage, and can be negatively impacted by changes in both the aquatic and terrestrial environments. The process of metamorphosis, which typically occurs in an aquatic environment (or at least an aqueous one–think about the bromeliad treefrog!), is biochemically sensitive. For these reasons, some refer to amphibians as the “canaries in the coal mine” of ecosystems.

Olympic Peninsula, Washington
Northern Red-legged Frog (Rana aurora) at Olympic National Park, Washington. In some places, the ground-cover vegetation of the temperate rain forests of the Pacific Northwest is alive with amphibians.

As a photographer, one of my favorite subjects is hunting waders: please see Stalking the Hunters. Along with fish, crawfish, and aquatic insects, amphibians (primarily frogs and tadpoles, and to a lesser extent salamanders) form a staple of the wader diet. Other predatory birds, Loggerhead Shrikes, for example, also eat amphibians. Shrikes are fascinating birds known to kill their prey by impaling it on sharp objects, usually thorns. On one, and only one, occasion we heard what we thought was a frog call coming from above. We looked up to notice a Loggerhead Shrike on wire over a frog-filled bayou. Was this a simple case of mimicry? Or deception—trying to get a frog to divulge its location? Research turned up no mention of Loggerheads making frog calls. Shrikes are known to deceive each other away from kills with frightening false alarm calls–so they’re not above trickery. The Asian Rufous-backed Shrike is an accomplished mimic, and, of course, the Northern Mockingbird is known to mimic frog calls, but a Loggerhead Shrike? We will continue to keep our eyes and ears peeled for this phenomenon.  If we heard what what we think we heard, we hope the time a Shike’s frog-call goes unanswered never comes.

Shrike-impaled Green Tree Frog on rose thorn, Sabine Woods, Texas
Green Tree Frog (Hyla cinerea) on Rose Thorn. Elisa captured this macabre image of a Loggerhead Shrike-impaled tree frog at Sabine Woods, Texas Gulf Coast. The shrike had just killed this frog and a mouse, whose decapitated body was impaled on some more rose thorns and whose head was impaled on some nearby barbed wire. As soon as Elisa finished the shoot and walked away, the shrike returned and reclaimed the mouse’s head.

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

A Quest for Rare Birds?

As we’ve grown older, Elisa and I, like many people, have agreed to slowly divest ourselves of many of the material things that clutter our lives. I, for example, have decided that if I buy a new book, then I must discard two old books. If I acquire a trinket, I must discard two, and so on. As part of this process, we have decided to collect experiences and images rather than material objects. Birding is very much a part of this process. Becoming serious about birding has forced us to think about visiting places and acquiring experiences that we would have never considered before–for there is no reason to visit some of these places other than the birds. Many birders have life lists of species that they have observed. But as a near-novice birder, I have purposely avoided this approach because I fear that this would turn birding primarily into a quest for rare birds. Perhaps as I gain experience in birding I will switch to a “life list” philosophy, but for now I find as much interest and joy in a common sparrow as I do in the rarest of birds.

Whooping Crane at Aransas National Wildlife Refuge, Texas Gulf Coast
Whooping Crane at Aransas National Wildlife Refuge, Texas Gulf Coast. With only about 600 individuals surviving in the wild and in captivity, Whooping Cranes are among the rarest birds in the world. These majestic birds, the tallest in North America, summer in the Canadian Arctic and winter along the southern Texas Gulf Coast. Photo taken from a boat.
Swamp Sparrow at Brazos Bend State Park, Texas
Swamp Sparrow at Brazos Bend State Park, Texas. Swamp Sparrows are common but delightful winter residents along the Texas Gulf Coast. Photo taken near Pilant Lake.

 

© 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.

golden-silk-spider-banana-spider-golden-silk-orb-weaver
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.