What we achieve inwardly will change outer reality. –Plutarch
This week on Galveston, Common Loons could be seen in many stages of transitional plumage. Every bird looked slightly different. All the birds I saw had some degree of spotting on the wings, and so lacked the brown, scalloped pattern of nonbreeding wing plumage. I saw one bird with a shaggy mane of pin feathers (Thanks to S.M. for pointing out this bird!) and one bird in almost complete breeding colors—only a stray feather here or there needed to be pigmented.
Many birds were engaged in hunting behavior much of the time. I saw fish, crabs, and a single mantis shrimp (Squilla empusa) being taken. This is clearly the time of year to be gorging and fattening up. It’s a long way back to Canada and environs for the breeding season! A good deal of preening was also going on, likely related to molting and keeping feathers in shape for the big trip ahead. Two birds had already pair-bonded and spent a significant amount of time together–another reminder that breeding in birds is often a process that unfolds in many stages over much of the year.
Feet, what do I need you for when I have wings to fly?—Frida Kahlo
Among extant birds, grebes have a unique method of foot propulsion. There are other foot-propelled divers, loons, for example, but these birds have significant webbing between the toes. The birds with webbed toes push themselves forward against the drag force of water. Grebes, on the other hand, have separate toes with stiff, collapsible asymmetrical lobes on each side. The lobes on the inside are larger than those on the outside. Grebes are also unusual in that their relatively short femora (thigh bones) are oriented perpendicular to the long axis of the body, and the toes beat along a complex dorso-lateral to ventro-medial path, rather than parallel to the direction of the body’s forward motion.
The traditional interpretation of how grebes paddled through the water, and the one I was taught, is that the lobes of the toes would unfold during then power stroke to provide maximum drag to push against, and fold up to reduce drag on the the recovery stroke. A more recent interpretation is that the grebe foot acts like a (slotted) hydrofoil and provides a lift force that propels the bird forward from behind (Johansson and Norberg, 2001)–physically similar to the way in which a wing allows a bird or airplane to fly. The lift hypothesis has an immediate visceral appeal to me given the asymmetrical lobes of the toes—like the vanes of a flight feather. Lift is usually explained by elementary physics textbooks as the result of the Bernoulli principle, essentially the conservation of energy for a moving fluid. This explanation is not correct quantitatively. The true explanation likely involves the most terrifying of all physics concepts . . . turbulence . . . .
As a photographer on the surface, I haven’t been able to document the strange way in which grebes move through the water. Once and a while, when conditions were right, I have been treated to a glimpse of the legs in motion as in the image below. Swimming with grebes is one more activity to add to an already lengthy bucket list.
I mentioned at the opening that grebes were unique among extant birds. Hesperornithiformes, a group of toothed Cretaceous foot-propelled diving birds, are thought to have had a method of propulsion similar to grebes and to have possessed asymmetrically lobed individual toes. On a recent visit to the New Mexico Museum of Natural History in Albuquerque, I had the opportunity to study the feet of a life-sized model of Hesperornis regalis, the largest of these Cretaceous divers from the Kansas Chalk Sea. Reading the label . . . sure enough, reconstruction supervised by Dr. L. D. Martin, my late (paleo)ornithology professor, a gifted teacher with so many fascinating stories to tell about the lives of birds. . . .
While grebe-watching, I am always interested in seeing these birds return to the surface with prey. In my experience along the Gulf Coast, Eared Grebes rarely return to the surface with prey. After dozens of dives, I have seen only one small fish clamped in a beak. This means that grebes are either remarkably unsuccessful hunters (unlikely), or that they can swallow small prey underwater (likely). Pied-billed and Least Grebes can be seen with large prey on the surface like fish, crawfish, frogs, and dragonflies. Perhaps small prey may be easily swallowed in the submarine realm, whereas large prey items may need to be manipulated into an ideal orientation in the air. In any case, grebes are certainly among the most interesting subjects for study and observation. Elisa doesn’t have to ask me twice to go grebe-watching!
Johansson, L.C., and Norberg, U. M. L. Norberg. 2001. Lift-based Paddling in Diving Grebe. The Journal of Experimental Biology204: 1687-1696.
Birds are the most popular group in the animal kingdom. We feed them and tame them and think we know them. And yet they inhabit a world which is really rather mysterious. –David Attenborough
Frankly we haven’t gotten out much lately. This is a function of terrible weather and just plain exhaustion. The prospect of fighting traffic on a gloomly, humid 85° day in February hasn’t held much charm. Spending time indoors has led to combing through the photo archives and pining for past years in which we had a proper winter.
One of the things we would have been watching for this week, had we been outdoors, is the cooperative feeding behavior of American White Pelicans. Whenever I see these birds I stand in awe, just waiting for them to so something neat. Is there anything more majestic in American birding than a string of White Pelicans paddling in formation along the shallows searching for schools of fish?
American White Pelicans are known to cooperatively herd fish into the shallows by beating their wings. On Galveston, a fairly common sight is a line of White Pelicans suddenly forming a circle, beaks pointed inward, and gobbling up a school of fish (presumably).
Once the feeding frenzy is over, the birds turn around within their circular formation and reassemble into their line and continue paddling along peacefully . . . until the next school of fish.
Digging in the dirt
Stay with me I need support
I’m digging in the dirt
Find the places I got hurt . . . . —Peter Gabriel, Digging in the Dirt
When birds are not around, the bird photographer must find other critters to photograph. Often that honor falls to ground squirrels and kin! As is my usual methodology, I research the animals I encounter in the field. Just as in the case of birds, ground squirrels tell a mixed story of success and struggle in a human-dominated world.
Not surprisingly, we’ve really only seen ground squirrels that are doing pretty well (for the most part) since we haven’t yet mounted specific expeditions to see and photograph the rare and threatened ones like the Mohave, Townsend’s, or Washington ground squirrels. Make no mistake, some ground squirrels are battling for survival against many of the same menaces facing birds–habitat destruction, cats, and poisons.
Although technically considered a species of “least concern,” the areal extent of Black-tailed Prairie Dog colonies has fallen to about 2% of historical levels. Considered by many farmers and ranchers to be pests (Get the bazooka, Joe!), these burrowing rodents are lynchpins of their local ecology. They have many interesting ecological relationships with a variety of other organisms. Birders might be concerned about their fate given their role as prey to a variety of raptors including Red-tailed and Ferruginous Hawks and Golden Eagles. Also, Burrowing Owls will nest in prairie dog burrows (and the burrows of many other mammals, as well). In 2004, the black-tailed prairie dog was removed from consideration for endangered status based on population studies. One wonders what the level of concern would be if the range of human distribution decreased by 98% in a century and a half. I bet everyone would think everything was OK.
The rock squirrel is a suspicious fellow we see occasionally on outings in West and Central Texas and Arizona. This is a big, dark chunky squirrel that is way more timid than one would expect given its heft. Try and flush one of these characters into a pillowcase, BM! At places like Franklin Mountains State Park and Lost Maples State Natural Area, these seed-hogging marauders can often be seen emptying the bird feeders of seeds. In contrast to the prairie dog, this is not a popular squirrel among the birds—nor likely anyone maintaining a seed feeder within its range (Get the blunderbuss, Bob!).
Although relatively little is known about its ecology, the Uinta ground squirrel is easy to spot at Yellowstone National Park. There are no known threats to its survival, especially since a big chunk of its limited range falls within that park in Idaho, Montana, and Wyoming. These critters are considered by some farmers to be agricultural pests (Arm photon torpedoes, Scotty!) because of their unforgivable tendency to dig and root up plants.
Now that we’ve seen quite a few species of squirrel, tree and ground, I have started paying more attention to them. When in a strange place, I’ve stopped assuming every squirrel I’ve seen is a common species (or subspecies) I’ve seen a hundred times before. For example, turns out a patch of habitat we bird occasionally (Cave Creek, Arizona) is home to the Mexican fox squirrel. Maybe next time I’ll capture a nice image of this cheeky critter!
It’s very far away,
It takes about half a day,
To get there, if we travel by my, uh . . . dragonfly—Jimi Hendrix, “Spanish Castle Magic”
Well, it finally happened. After five brutal months, the first cool front of fall 2016 arrived. And we returned to the field. In just a few weeks’ time, I found that my photography skills had atrophied a bit, but in an hour or two I was getting some nice shots again. On Saturday, I visited Lafitte’s Cove and found Prothonotary, Palm, and Magnolia Warblers, a lot of Gray Catbirds, Brown Thrashers, and mosquitos without number.
On Sunday, we visited Brazos Bend State Park and observed a flood-disrupted ecosystem. Major portions of 40-acre, Pilant, and Elm Lakes were covered with invasive water hyacinth, and hunting waders, the birds we love to see most at the park, were nearly absent. Here and there, large patches of dead hyacinth revealed where park employees had sprayed herbicide. At both Lafitte’s Cove and BBSP, the real story was about arthropods, though, and at BBSP we spent an extended visit with naturalist friend and park volunteer R.D., from whom we learned more about spiders and dragonflies.
Along the tower trail at BBSP we saw many golden silk orb-weaver spiderwebs. In many webs, entrapped prey and fallen leaves could be seen. We observed several instances of spiders cutting leaves free from their webs. Perhaps the most interesting phenomenon we observed was dewdrop spiders stealing food from the web of their host. Dewdrop spiders are kleptoparasites of the Genus Argyrodes. Although some researchers have questioned whether or not dewdrop spiders were harmful to the orb-weavers (and therefore not parasites), recent studies have documented that the host spiders suffer nutritionally and must repair damage to webs caused by the small spiders as they remove entangled prey. Apparently spiders take better care of webs that theythemselves spin!
The green darner (Anax junius) migration was in full swing, the air filled with millions of these large dragonflies, many mating. Lots of other dragonfly species were zipping around, too. Black saddlebags (Tramea lacerata), many also coupling, even seemed to predominate at Lafitte’s Cove. Dragonflies are an important food source for birds, and I have seen several species of waders (Snowy and Cattle egrets, and Little Blue and Green Herons) and one species of warbler (Prothonotary) eat them at BBSP.
Although dragonflies seem to be a favorite food among birds, orb-weaver spiders seem not to be. Big, juicy spiders sit right out in the open while predatory birds typically operate all around them. The orb-weavers would certainly be easier to catch than a dragonfly. Perhaps the arachnids taste bad. I have heard anecdotally, though, that during drought years the orb-weavers essentially disappear from the park. Does this mean that birds will eat them if they get hungry enough? Other possibilities do exist (like humidity-sensitive fungal infections of spiders or eggs), but the report is certainly food for thought.
Remembrance of things past is not necessarily the remembrance of things as they were.―Marcel Proust
The world is old. The world is new . . . .
Over the past few weeks we’ve made a few tepid efforts to get back into the field, mostly binocular birding. After an hour or so, I was dragging along on my heels, round-shouldered, and dripping with sweat. But the first hint that fall might arrive someday is in the air in the early, early morning hours. The sky and clouds may have just a hint more peach and pink. It’s not quite so broiling, at least for a few of these early hours.
Down at Bryan Beach we did see a few things of note. Horned Larks were hunting insects among the beach flotsam. A Ruddy Turnstone was engaged in a life-and-death battle with a large buprestid beetle. This year’s crop of young Wilson’s Plovers were everywhere. In a previous post I remarked about how much this area reminded me of the the great Western Interior Sea of the Cretaceous Period . . . .
Like Billy Pilgrim, I sometimes find myself free of the confines of a particular time. Growing up on a land shaped by glaciers–moraines, eskers, and potholes–and half the year covered in drifting snow, whipped up into sparkling wisps, it was easy for a kid to stare squinting into a world that dissolved into Clovis hunters in fox and ermine parkas, perhaps, like Eskimos, sporting stylish ivory sunglasses, pursuing herds of mammoths and musk oxen across the ice-pack.
From time to time, I find myself in haunted places that make such time travel easy.
The Hoh Rainforest of the Olympic Peninsula is one such place. Russell Cave is another. The Hoh Rainforest is a misty woods, its mightly conifers draped in moss, and the forest floor covered in ferns. In such forests 150 million years ago the proto-birder could likely have heard the squawking of Archaeopteryx or Microraptor in the canopy as they waited for a stegosaur to lumber past. But steer clear of the giant bison hunters of Russell Cave. They’re a rough lot.
For a minor creative project I’m working on, we took a trip to Mercer Arboretum and Botanical Garden. I was interested in taking a few images of primitive plants in the Prehistoric Garden. In the garden are a number of types of plants representing groups that date back to the Mesozoic Era, and in a few cases even the Paleozoic Era. We saw the maidenhair tree (Gingko biloba), ferns, tree ferns, cycads, dawn redwood (Metasequoia glyptostroboides), and several strangely wonderful Araucaria conifers (including the Moreton Bay pine, A. cunninghami, and the bunya-bunya, A. bidwillii).
Spinkled throughout the gardens we saw other plants of nearly equal antiquity. Magnolia and sycamore, for example, date back to the Early Cretaceous Epoch. On this trip we even saw a tyrannosaur eat a guy! I swear!
I have called this principle, by which each slight variation, if useful, is preserved, by the term of Natural Selection. –Charles Darwin
On our most recent visit to Buffalo Run Park in Missouri City (8/6/16) it seemed that some of the Orange Bishops (Euplectes franciscanus) were a different color than during previous visits. In mid-July, I thought that all the males were orange and black (with a muddy orange-brown mantle) and a hint of red in the throat.
The redness of the throat was heightened when the birds went into display mode as you can see in the images immediately above and below. The red color could be structural (due to the physical optics of the feather), a result of pigmentation, or both. It seems likely that this red color could be in part structural, like the colors of a hummingbird gorget, but for reasons discussed below it seems unlikely that the red is due to this alone.
On August 6, I saw a number of birds that were clearly more red than orange. Because the difference was so striking, I wondered if these redder birds were actually a different species, namely the Southern Red Bishop (Euplectes orix). Some quick research revealed that the Southern Red Bishop is not kept as a pet for some reason and thus not likely to be found in pet shops, the ancestral source of the Buffalo Run birds. Also, although very similar in general appearance to the Orange Bishop (aka, Northern Red Bishop), the black face mask of the southern species extends around the bottom of the lower bill into the throat. The birds at Buffalo Run Park, then, are clearly the northern species.
Color in birds is a fascinating and complex subject involving some rather difficult physics and biochemistry. Color can be a function of both pigmentation and physical optics (interference and diffraction) of light as it passes through the feathers. Reflection from lighter feathers beneath the outer feathers is also implicated in some avian colors. Interestingly, the color of birds can be affected by diet, especially in the case of yellows, reds, and oranges which are derived from ingested carotenoid compounds.
As a test of whether the red color in the redder Orange Bishops was structural, I was sure to capture images of the birds facing into and away from the sun (below). I would expect differences in appearance if the color was structural, much as a hummingbird looks different when illuminated from different angles. I noticed no change in color due to direction of light in the case of the redder bishops. Likewise the orange Orange Bishops appeared very similar facing into and away from the sun, with the exception of the throat. The two birds above are facing into the sun, and the bird in an earlier post was facing away from the sun.
For these reasons, I suspect that pigmentation is involved in the red of these birds. But this begs a number of other interesting questions. If carotenoid pigments are often involved in the warm colors, and these compounds are found in the diet of birds, how is it that bishops look the same in Africa as Texas? Surely they are not eating exactly the same plants. Or are they? Is it natural for bishops to redden into a deeper red later in the breeding season? If so, is this due to diet or genetics or both? Are the red versus orange birds simply a matter of individual variation, the stuff of natural selection? A few hours chasing African birds around on a sweltering Texas morning has provided more questions than answers.
Finally, although the females are very sparrow-like in appearance and much more shy and difficult to photograph than the males, I made several attempts to maneuver close to them for an image. I would note that, ultimately, color in breeding male birds is all about female breeding preference. Buffalo Run Park could be natural laboratory for the study of how invasive species adapt to a new environment, specifically breeding in a new context. I foresee a master’s thesis for some budding young ornithologist.
Those who live by the sea can hardly form a single thought of which the sea would not be part. –Hermann Broch
Over the past week or so, I’ve made several dawn and dusk visits (once with Elisa) to the East End/East Beach area to observe and photograph summer shorebird behavior—which abounds at this time of year. Unfortunately by 8 am the area has been a blazing inferno, making photography a challenge.
In an earlier post I mentioned the appearance of a new tidal channel near the East End Lagoon Preserve. This week I took a look-see to find out the status of the new channel and the impact it might be having on the wildlife of the area. As I expected, the channel has expanded: it is now about twenty yards wide at the mouth during high tide. A Reddish Egret patrolled the channel mouth while Laughing Gulls, Royal and Sandwich Terns, and the odd Willet mostly stood around while I photographed them. They were taking some interesting prey, though.
During the warm months, a strange, eel-like fish, the Atlantic cutlassfish (aka ribbonfish), is abundant in the bays and channels along the Texas Gulf Coast. Laughing Gulls and Royal Terns were having a field day eating them this week. Although the birds consumed them enthusiastically, both species seemed to have difficulty swallowing the fish’s long, thread-like tail. Some birds were walking around with a silver thread trailing out of their beaks!
The real story at this time of year on Texas beaches and barrier islands is, of course, breeding. The Royal Terns, Least Terns, and to a lesser extent, the Sandwich Terns, clearly had mating on their minds. Royal and Sandwich Terns were doing some dancing. Male Royal Terns and Least Terns were presenting females with a nuptial gift of small fish. A few Least Terns were nest-sitting. Some Royal Terns were copulating right out in public. Gracious! What will the drunken fishermen think?
Plovers, too, were everywhere on the East End of Galveston. Wilson’s Plovers were breeding along with Least Terns in the protected areas. Snowy Plovers were running around everywhere, but likely not nesting—their coastal nesting areas are further south in Texas. A few Black-bellied and Semipalmated Plovers were standing around trying to look innocent—as if we didn’t know that they are tardy for an appointment in the high-Arctic. Or perhaps they are among those rare birds that reside in Texas during the summer but do not breed?
Finally, lending a splash of color to the seascape were American Avocets in breeding colors. These birds are either very late spring migration stragglers or belong to scattered clusters of birds, rare summer residents, that inhabit the Texas Coast. Whatever their story, it’s nice to be able to see shorebirds in breeding (summer) and non-breeding (winter) plumage at the same locale.
Anything can happen in life, especially nothing.–Michel Houellebecq, Platform
Lately interesting bird sightings have been as rare as intelligent discourse during a presidential election or quality programing on network TV. The last few weeks of iffy weather and striking out on scouting expeditions to places we’ve never visited before (or perhaps only visited a time or two years ago) and seeing little in the way of birds got me thinking: Hey! I don’t need any birds to do bird photography! I can just take pictures of where birds have been! It also got me reminiscing about the all the other times out birding when we saw nothing!
Of course, other than abandoned nests and footprints in the mud (or droppings on a post), if you’re looking for signs of past avian activity you’re pretty much looking for woodpecker handiwork. Woodpeckers are among my all time favorite birds and have been chiseling holes in trees for at least the past 25 million years, since the late Oligocene Epoch. I used to think that petrified wood was a pretty mundane fossil until I started reading about ancient woodpecker holes—now I’ll be checking those hunks of fossil wood and hoping! Incidentally, there is lots of petrified wood around the Texas Gulf Coast, but being mostly Eocene (56-34 mya) it’s way too old for evidence of woodpecker activity, though. Pity.
Finally, while watching a Hairy Woodpecker chisel holes in the side of some guy’s house in Colorado last summer, I just had to admire the panache and devil-may-care attitude. Never mind that the hapless owner probably toiled thirty years to pay off the mortgage: let’s blast some holes! There may be tasty grubs inside those 2×4’s! Like City of Houston road crews, hammering away and leaving a lunar landscape behind, woodpeckers work their magic and are on their way!
Conversation about the weather is the last refuge of the unimaginative. –Oscar Wilde
At some point during the winter, a major blue northern will, hopefully, blow through and stay. Until then we’ll check the radar and bore each other (and the ghost of Oscar Wilde) with endless conversations about the temperature, humidity, jet stream, and El Niño.
But even with the iffy weather, late fall and early winter seem to be the times for charming and oddball little discoveries. Last weekend the first real Arctic blast swept across Texas. Optimistically we headed to the Coast. But at 8 am Sunday on East Beach, Galveston the winds were howling so we aborted our attempts at shorebird photography (a strong wind can twirl the barrel of a supertelephoto lens around and conk an inattentive bird photographer across the skull!) and headed for Lafitte’s Cove.
Hoping the oak motte would expend some wind energy, we approached the trees. But alas, it was still too windy for big glass, and so we settled for binocular birding. On the way into the motte, we heard a Northern Mockingbird imitating the clattering call of a Belted Kingfisher—a first for us. Once in the trees, I spotted a Pine Siskin among a small group of American Goldfinches. This was my first ever sighting of a Pine Siskin on Galveston. Although (according to the literature) Siskins do rarely make it down to the Coast during winter, I have to think that this bird was blown off course by the massive cold front that had just arrived, perhaps 30 hours before.
In late fall/winter trees are bare, and as a result we see more songbirds than at any other time of the year. This is a good time to look for statistically rare individual color variations. Sometimes in winter, for example, it’s possible to observe diet-induced House Finch color variants, namely male birds with orange or yellow on their heads and throats (rather than red). I don’t know what the proportion of yellow- and orange-headed male House finches is—but it must be only one in dozens of birds.
This is also the time to really watch waders hunting. I’ve already mentioned the treefrog hunting that goes on around the southern margin of Pilant Lake (and I saw some more of that this week), but it seems that birds are having to work harder and are tapping somewhat atypical resources. The Little Blue Heron below, for example, was hunting in a patch of water hyacinth—and catching grasshoppers. Over the years I’ve watched Little Blues eat countless small fish, frogs and crayfish, but this is the first time I’ve seen one eating grasshoppers. Usually it’s Cattle Egrets that are grabbing katydids and grasshoppers. Perhaps times are getting a little lean, and everybody is a little less picky and willing to eat anything that moves.
Finally, the strangely warm and humid weather that has dragged deep into November has had one very nasty side effect: an explosion in the population of vicious biting gnats. I’ve always been sensitive to gnat bites, but these suckers raise huge itchy welts that hurt for days. On Wednesday of this week, gnats were so thick at Brazos Bend State Park that even the birds were being dogged by clouds of these nasties. So here I sit, hoping for a hard freeze to settle the bugs’ hash once and for all—and begin the real, lovely birding season.
The stratosphere is a hostile place.–Felix Baumgartner
As we continue to dig out from the flood nightmare . . . .
In March, I mentioned to a birder/naturalist friend (RD) that one of the nesting Great Horned Owls on the west side of 40-Acre Lake showed some signs of facial injuries or infestation by ectoparasites. He asked for more information. I have been slow honoring this request . . . but here goes.
Bird nests, especially those of raptors, are not hygienic places. The adult birds drag dead or moribund prey to the nest where it is torn apart and distributed to nestlings. Spilled blood and gore, as well as the birds themselves, are attractive to parasitic insects. Black flies (which incidentally carry avian malaria), for example, are known to be especially vexing to Great Horned Owls.
In the above image, the owl appears to have several small injuries around the eyes. What follows is pure speculation, but perhaps the owl got nicked up in a battle with prey. The wounds would naturally be attractive to egg-laying flies, which feed on necrotic as well as living tissues. The whitish objects on the left eyelid appear to be maggots.
What is interesting is that by the very next day (below) the region around the eyes is very much better (sidebar: this is clearly the same bird. Note the stray white fleck above the right eye in both images). The eyelids still appear injured and crusty, but no blood or maggots are visible. Perhaps this bird was able to clean itself up, or perhaps it got help in grooming from its mate. In any case, this bird appears to have had a brush with fate, and I for one am delighted at the outcome.
Sleeping is no mean art: for its sake one must stay awake all day.–Friedrich Nietzsche
Birds live in a dangerous world. Never is this more evident than when they are trying to sleep. Ground-roosting birds like waterfowl, shorebirds, and gulls can often be seen drifting in and out of sleep, one eye open, intermittently surveying the environment for dangers (and photographers).
Many birds sleep (or merely rest) with their heads supported on their backs, beaks nestled in the scapulars. This rests the muscles of the neck and keeps the delicate skin around the beak warm. Breath expelled into the feathers keeps the back nice and toasty warm. On some cold and windy days, it’s common to see sandpipers balanced on one leg (like the Sanderling on the right above). This, of course, reduces the amount of bare skin exposed to the hostilities of the environment.
Soon Texas birds will be much more concerned about keeping cool—and I’ll keep an eye out to document their interesting thermoregulatory behaviors!