Tuesday, November 29, 2011

Red-headed Meadow Katydid

Your narrator at work in the saw palmetto, photographing one of the coolest insects in the southern pine woods. Shortly into my recent foray into the Okefenokee National Wildlife Refuge, I was distracted by a very distinctive singing insect, the likes of which I had never heard. It was clearly one of the meadow katydids, but this species possessed an incredible booming voice. It sounded like a hopped industrial strength automated lawn sprinkler, and even with the distraction of chortling Red-headed Woodpeckers and the odd squeakabilly Brown-headed Nuthatches piping away, I easily noticed the bug's solos.

Being a bit of a student of these sorts of things, I figured the little singer must be the red-headed meadow katydid, Orchelimum erythrocephalum.

Into the scrub I plunged, and rather quickly hunted down the little fiddler. Bingo! A "life" insect, and one that I had wanted to see ever since crossing the red-headed meadow katydid's path in the lush pages of The Songs of Insects. In this dorsal, or top view, the animal may not look like much, but just you wait.

Wow! What's not to like about a red-headed meadow katydid? The deep blood-red face is an incredible contrast to the bug's lime and forest green overall wash, and the rear abdominal segments are also striped in red, creating an artistic complement to the fore part of the katydid.

I was instantly smitten with these red-headed meadow katydids, and hunted up and photographed several of them. The six-legged extroverts are not hard to find, once one is tuned in to their melody. LISTEN HERE. The singing males, such as above, typically mount the highest leafy perch available, and belt their song out to the masses. You could easily hear a singer from 75 feet away.

Meadow katydids, and this species in particular, are rather easy to befriend. Just slowly extend a finger towards the animal, and as it comes into range, the katydid will investigate you with its long wiry antennae. Detecting the presence of salts and other nutrients on your skin, presumably, it'll climb right aboard. Handling the animals in this way makes for fabulous photo ops.

I would like to know more of the variation in the red-headed meadow katydid. The Okefenokee insects appear more colorful and boldly marked than most of the images that I've seen, and the eyes seem more strongly blue. But the song is spot on with all of the recordings that I've heard.

Of course, befriending one of the larger katydids - and red-headed meadow katydids are bruisers in comparison with most of the others - brings on its risks. The reason they like to climb aboard us is to rasp at our skin. Katydids are facultative feeders, tending to graze on whatever is handy, and that's usually plant material. They have very powerful mandibles for crushing seeds and other hard objects, and occasionally can really put the pinch on, especially when they go for your cuticles. It's always fun to help encourage a katydid onto an uninitiated person's finger, and watch their reaction with the first strong nibble.

As I write this entry, the temperature outside is in the low 30's, and there are intermittent snow flurries. I wish I were back in Georgia's piney flatwoods, where the red-headed meadow katydid song resonates!

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Sunday, November 27, 2011

Red-cockaded Woodpecker

A beautifully maintained stand of longleaf pine, Pinus palustris, in the Okefenokee National Wildlife Refuge, southern Georgia. The scrubby palmlike understory is saw palmetto, Serenoa repens. This habitat is home to the rarest of North American woodpeckers, the Red-cockaded Woodpecker, Picoides borealis.

On my recent foray into the Okefenokee, finding Red-cockaded Woodpeckers was high on the list. As a consequence, I spent much time roaming the sandy pine flats. One of the first birds that will greet the pinewoods explorer is this charmer, the Brown-headed Nuthatch, Sitta pusilla. These inquisitive gleaners display great fidelity to one another, and a pair will forage together throughout the year. The birds more or less constantly emit a stream of squeaky chatters, and the notes sound like a dog's squeak toy ball.

A Brown-headed Nuthatch is truly elfin, weighing about ten grams and measuring only 4.5 inches. That's not much larger than a kinglet, and less than half the weight of a White-breasted Nuthatch.

It would be harder to find a more woodpecker-rich habitat than a Georgia pine woods. Red-headed Woodpeckers, such as above, were very common. We also had scads of Red-bellied, Downy, Hairy, and Pileated woodpeckers, Yellow-bellied Sapsucker, and Northern Flicker. In addition to, of course, our target woodpecker. At times, I would see or hear six species of woodpecker simultaneously.

A towering longleaf pine, the Red-cockaded Woodpecker's tree of choice. Longleaf pine forests have suffered terribly, with only an estimated 3% of the original stands remaining. The wood of this species is especially durable and valuable, hence the lumberlust by the timber industry. Many stands have been replanted to faster growing slash pine or other species that will generate a pulpwood crop within a few decades.

The massive cone of a longleaf pine, set off against its incredibly long, almost silky needles. To my eye, this may be the best looking of any of our native pines, and it has some serious competition in the beauty department.

Finding colonies of Red-cockaded Woodpeckers isn't difficult. Active nest or den trees or conspicuously banded with a white stripe. That doesn't necessarily mean the birds are easy to find, outside of the active nesting season. RCW's are social animals, and will forage in loose groups, but often wander some distance from colony sites. The trick is to get oneself in the vicinity of an active denning area BEFORE dawn. Then just stand quietly, and enjoy the animals as they emerge and begin calling back and forth and foraging. Chances are, within five or ten minutes they'll have flown off to distant feeding areas. At least that was my experience. Only once, in all of our pinewoods roaming, did we stumble into a foraging group at midday, and they were much harder to observe.

This is a natural RCW cavity. RCW's are the only North American woodpecker that excavates nest holes in living conifers. This habit is thought to be an adaptation that ups the odds of their survival in a habitat that is regularly subject to scorching fires. Older-growth pines are fire-resistant, thus the tree - and woodpecker nest - are likely to survive conflagrations.

Another interesting aspect of RCW nest cavities is the birds' propensity for drilling sap wells around the cavity's perimeter. By doing so, the woodpeckers trigger a sheet flow of gummy, sticky sap all around the nest site. The likely theory for this is that the tarry sap impedes the ability of predators such as high-climbing rat snakes to gain access to the hole. Plenty of viscous white pine sap is evident in the photo above.

This is a nonnatural RCW nest cavity. A box with an appropriately sized entrance hole is placed high on a pine, in an excavated cavity. The biologists who install these are quite good at it, and the structure can blend remarkably well with the tree. It is thought that artificial cavities have helped to bolster RCW populations. There still aren't many birds. About 14,000 birds are all that's left.

Finally, the Red-cockaded Woodpecker. Sorry for the lack of National Geographic quality images, but I made these photos at the cusp of dawn, when light was dim and the birds were not very close. We can see the complete ladder-backed appearance here; RCW's lack the central pure white back of Downy or Hairy woodpeckers, which are the most likely source of confusion. The RCW slots in between those two species in the size department.

No mistaking an RCW from this angle. That big white cheek is a dead giveaway. Like most woodpeckers, RCW's are also rather vociferous and its likely you'll hear them before making visual contact. They give a loud, rather sharp but nasal squeak, suggestive of an effeminate Hairy Woodpecker.

Red-cockaded Woodpeckers are intimately linked with fire, one of scores of species that in effect rise from the ashes. Fire maintains the open savanna-like pine groves that is optimal breeding and foraging habitat. For as long as there have been longleaf pine forests, fire has been a factor, regularly sweeping through and clearing the habitat. As foresters entered their 20th century love affair with Smokey Bear, fire suppression became the norm, and lots of fire-dependent animals and plants suffered. The science of fire ecology has made great strides and we have a much better understanding of the role of fire in ecosystems. As a result, RCW's, Karner blue butterflies, wild lupine and many other species are rebounding.

The Red-cockaded Woodpecker was listed as an endangered species in 1970; thus it was among the first group of animals to gain protection under the federal Endangered Species Act with its passage in 1973. At that time, fewer than 10,000 RCW's existed. With protection of its habitat and management techniques, the woodpecker population has grown by one-third. That's still precious few birds. I certainly hope this iconic bird of the southern pinewoods never goes the way of its larger cousin, the now extinct Ivory-billed Woodpecker.

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Friday, November 25, 2011

Green Lynx Spider

A fiercely protective female green lynx spider, Peucetia viridans, stands guard on her nest. This one had chosen a fruiting cluster of seedbox, Ludwigia alternifolia, in which to weave her saclike structure. The females are big spiders. Her body is nearly an inch in length, and throw in the legspan and you've got an animal that would pretty much cover a silver dollar. You'd notice this thing if you felt the tickle of one crawling up your arm.

We found this spider and several others of its species in a bramble patch in an open longleaf pine flatwoods bordering the Okefenokee Swamp in south Georgia. I had never seen a green lynx spider before, but figured that it must be some type of lynx spider as soon as I clapped eyes on the beast. We've got a much smaller species in Ohio, the common lynx spider, Oxyopes salticus, and it is widespread and often abundant. It too is colorful and has impressively spined legs.

Note all of the spiderlings surrounding mom. If nothing too big and menacing happens by, they're probably in good hands. As I moved in close for these shots, the female spider would move with me and even seem to make hostile advances. Lynx spiders are active hunters, stalking the shrubs and attacking prey. They use those formidable spines that armor their legs to snare and box in their victims; sort of an Iron Maiden embrace of doom.

To my eyes, the green lynx spider is an impressive, good-looking arachnid. I'm glad that I was able to spend some quality time with these brutish animals.

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Thursday, November 24, 2011

Some Okefenokee scenics

Before long, I want to share some up close and personal accounts of some of the interesting critters and plants that I encountered on my recent foray into the Okefenokee Swamp. But whether one knows the names of any of this vast wetland's flora and fauna, they'd certainly be impressed by the scenic grandeur of the place. Following are a few photos of the Okefenokee's picturesque beauty. As always, clicking on a photo will enlarge it.

An Okefenokee skiff. Boats with shallow drafts are essential for navigating the marshes and waterways. A big thanks to guide Jennifer Iona Hogan with Okefenokee Adventures for showing me some off-the-beaten-path places. Look her up and take a tour if you make it to the Okefenokee.

Stately cypress trees draped with Spanish moss create lush walls of vegetation along blackwater canals.

Cypress trees are deciduous conifers, and most have dropped their needles by now. However, in places the trees were still burnt-orange with old needles.

Big skies over wet prairies. Such places abound in life, both plant and animal.

Okefenokee "prairies" are really vast sedge meadows. An indescribable bounty of wetland animals call these marshes home, at least seasonally. I saw everything from tiny citrine forktail dragonflies to massive Sandhill Cranes.

An abundance of pine flatwoods surround and intersperse the wetlands. Spiny-stemmed saw palmetto underlays the pines. This habitat supports a different cast of characters, including the federally endangered Red-cockaded Woodpecker.

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Into the Okefenokee

I'm just returned from an immersion into one of our country's most iconic wetlands, the sprawling 400,000+ acre Okefenokee Swamp of southern Georgia and northern Florida. An in-depth look into the Okefenokee had long been on my list, and after spending three days exploring its fabulous habitats, I have a much better understanding of this incredible place. As always, many photos were made, and plenty of interesting creatures were found.

The still black waters of the Suwanee Canal are often described as "mysterious". I suppose that's an understandable thought, as one can't see more than a few inches below the surface. As gators, moccasins, and other potentially scary critters lurk in the depths, the Okefenokee waters are indeed mysterious to most.

I was able to penetrate a fair ways into the swamp on a skiff, and see lots of interesting terrain. The Okefenokee is a place of great beauty, its tannin-stained waters refecting the images of golden-needled cypress and blue skies. Excepting the occasional boatload of touristos traveling down the canal, there are no people and the swamp is far from the hubbub of highways and towns.

Alligators aplenty roam the Okefonokee. An estimated 10,000+ of the massive reptiles swim in the swamp, and if the temperatures crest 60 degrees, you're sure to see some.

Your blogger far out in one of the Okefenokee's "prairies". It was a real treat to have the chance to wander far off the beaten path and into some of the massive wet meadows of the Okefenokee. I am standing in a sea of horned beakrush, Rhynchospora inundata, and other wetland sedges.

Okefenokee is a Choctaw word meaning "quivering earth", and it isn't hard to see why it's called that when walking across the soggy quaking peat. I saw some great plants out in the prairies, including a fabulous botanical carnivore.

I'll be back soon with some closer views of some of the Okefenokee's extraordinary flora and fauna.

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Tuesday, November 22, 2011

Okefenokee Swamp

I'm deep in south Georgia, in the heart of Okefenokee Swamp country. Laptop/Internet issues prevent a detailed photo post,  but those will come soon. I'm seeing all manner of cool stuff, and obtaining scads of images. Everything from gators to Red-cockaded Woodpeckers! Posts to follow soon.

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Friday, November 18, 2011

Wheel bugs rule!

A wheel bug, Arilus cristatus, in repose. These beneficial native assassin bugs are ten kinds of cool, squared. I always consider it a treat to encounter one, and have shown many people their "life" wheel bug. Invariably, they are impressed. Of course, I would explain the valuable roles that they play in nature, and the incredible mechanics of the beast. These prehistoric-looking insects truly are miniature works of art, and deserve our respect.

Thus, I was mortified when I encountered an alleged "news story" about the fearsome wheel bug. The reporter used bizarre inflammatory rhetoric to describe these small insects, such as "The horrific monster or insect..." I'm not kidding. As he spouted this sort of nonsense, he whipped up some local Pittsburgians into a frenzy of fear over the terrifying wheel bugs. It was as if an army of six-legged Vlad the Impalers had descended upon the bucolic Pennsylvania neighborhood.

WATCH THIS SILLY VIDEO HERE. Then, on behalf of wheel bugs everywhere, I would encourage you to leave a comment on their website that protests this ridiculous bit of "journalism", and stick in a good word for the bug!

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Wednesday, November 16, 2011

Black-tailed Gull in Ohio!

Photo: John Pogacnik

A first state record Black-tailed Gull was found this morning by Craig Holt at the harbor at Ashtabula, Ohio on Lake Erie. Word traveled quickly and a number of people were able to get to the site this afternoon and relocate the bird. Thanks to John Pogacnik for the documentary photo, above.

The Black-tailed Gull, Larus crassirostris, is an Asian species that is a very rare vagrant to North America. There are only a few records from the Great Lakes, and as previously mentioned, no priors from Ohio.

I'll be in Ashtabula bright and early tomorrow, and hope to see the animal. More reports/photos may follow.

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Tuesday, November 15, 2011

Carolina Wren with caterpillar

Photo: John Howard

John Howard shared this beautiful photo with me a while back, and I wanted to in turn share it with you. He has caught one of the bird world's premier fuss-budgets, a Carolina Wren, Thryothorus ludovicianus, just after it snagged a fat caterpillar. For this little rotund red-brown ball of feathers, eating that cat will be about like one of us scarfing down a footlong hotdog.

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Monday, November 14, 2011

The songs have faded...

I really miss the song of autumn about now. This afternoon, I took a brief wander through the local patch, and heard only the feeble swan songs of Carolina and Allard's ground crickets. These little black crickets are the toughest of our Orthopterans, or singing insects, and we'll hear the odd individual fiddling its wings into early December, if the sun shines brightly enough.

But for the most part, the entomological symphony, that grand wall of sound created by legions of katydids, coneheads, trigs, and crickets is gone. The singers have perished, leaving only their eggs to ride out the winter, and it'll be next summer before their life cycle comes once again to the point of music.

Just two weeks ago, I found myself in some marshy ground on an unseasonably warm day, and the singing insects were going whole hog, every bit as active as a bunch of drunks in a Karaoke bar. This black-legged meadow katydid, Orchelimum nigripes, was especially extroverted so I paused to pay him some mind.

By November, the males are pulling out all the stops in a last ditch effort to woo a female. They know, intuitively, that their days are severely numbered. If they are to leave spawn, it is time to sing with all one's might! Attracting a girl is the ONLY thing that matters at this point.

This black-legged meadow katydid was really going at it, and was not much bothered by your narrator sticking a brightly flashing Nikon in its grill. The paler brown region on the katydid's back is its stridulatory region of the wings, and he was rapidly rubbing them as I took the photo. As were scores of others. That day, October 30, was the last day that I heard a full-bore salvo of insect song.

Meadow katydids might be considered the most charming of their ilk. There are a number of species, but all are neatly packaged and rather showy. As is the case with our melodious insect songsters, they sport exceedingly long antennae - far lengthier and more ornate than any grasshopper. The husky sputtering trills of meadow katydids are a ubiquitous sound of summer and fall, lisping forth from meadows and other unkempt open spaces. To my ear, they sound somewhat like an ill-tuned lawn mower firing up, or perhaps the mechanical clicking-ticking of an automated lawn sprinkler.

video

Click the short video above, and you can hear the meadow katydid for yourself. We'll have to make due with such digital fare for some time, I'm afraid, if its katydids we wish to hear. July is a long ways off.

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Sunday, November 13, 2011

Bug Guide rules!

A tiny European tube wasp, Ancistrocerus gazella, laps nectar from one of the season's last Canada goldenrods. I was out a week ago on a brief photographic interlude, and stumbled across one of these miniature beauties. As is often the case with bugs, I didn't know what it was.

I do know enough about entomology that I realized it was a wasp, and that at least provides a starting point. But just knowing that generality wasn't good enough. I am without doubt a born taxonomist, although I don't say that to mean that I am a good or gifted taxonomist. It's just that I can't stand NOT knowing the name of something. I don't like generic identifications.

Aspiring to know the name of every creature one encounters brings a certain set of problems. Especially in the world of bugs. One would quickly be driven mad, and use every minute of their waking hours, trying to pin names on every insect encountered, at least if you're in the field a lot and looking hard at things.

I was particularly curious about this micro-wasp for two reasons: it was striking in appearance; and it was a species that I was pretty sure I hadn't yet come across. So, after obtaining these so-so images - but they do show diagnostic characters - I set out to name it. Fortunately, I soon stumbled into THIS PAPER, which does an admirable job of delineating our vespid wasps. Largely by matching photos, I came up with an identity of Ancistrocerus gazella.

However, the wasp world is enormous, and there are plenty of look-alike species. Also, in this case, I could find no reference to this introduced species of wasp as being recorded from Ohio. So, where to turn for expert input?

Bug Guide!

This website is certainly the most comprehensive and awesome library of insect information on the Internet. Legions of experts and specialists routinely lurk there, and they are often quick to pin names on photographs of mystery bugs that are submitted. I uploaded my wasp photos, asking for a confirmation of my identification, and eventually Richard Vernier chimed in and reported that it was indeed the European tube wasp, Ancistrocerus gazella. Excellent!

Insects rank high on the list of animals that people wish to name. It's a vast and confusing world, and pinning a tag on that strange beetle that was in your basement can be tough. A trip to Bug Guide can help solve the mystery.

By the way, if anyone knows the status of the European tube wasp in Ohio, please let me know.

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Thursday, November 10, 2011

Snow Buntings

Resplendent in their rust and cream feathered finery, three Snow Buntings, Plectrophenax nivalis, pose on a piece of Lake Erie driftwood. I encountered these hardy little "sparrows"* a few weekends back, and spent nearly an hour stalking and observing them. This trio was part of a group of a dozen birds, and by moving slowly and cautiously, I was allowed to infiltrate their ranks and make some interesting observations at arm's reach.

*Dammit one thousand times over! The taxonomy of birds is in an ever-increasing state of upheaval, and snow buntings are now no longer placed in the family of true sparrows, the Emberizidae. They, along with the longspurs, have been segregated into the Calcariidae family, or longspur family. I am still referring to snow buntings as sparrows until I come to accept this change.

As is often the case with birds that are habitual ground foragers, Snow Buntings walk, rather than hop. Walking is a more efficient form of locomotion for ground-bound birds. When a pack of buntings bursts into flight, they become quite conspicuous, as if a sudden gust blew giant snowflakes in to the air and is swirling them about. Bunting flight is invariably accompanied by their dry throaty rattles punctuated by clear musical TSEW! notes. But when on a sandy substrate or in a barren field, the buntings seemingly vanish, their patterns that are so bold and contrasty in flight now serving to match them to the earthy tones of the soil. Their rather sluggish mousy waddling gaits when at ease further serve to make detection difficult.

I was especially interested in the buntings' feeding habits. It wasn't long before one of my subjects ambled into a tuft of grass, and began piggishly plucking the fruit from the plant. This is not just any old grass, though - it is purple sand grass, Triplasis purpurea, which is a rare plant in Ohio. For the most part, this grass is confined to sandy beaches along the Great Lakes in the Midwest, and it in general is not common in the southern reaches of its Great Lakes distribution.

As Snow Buntings are quite fond of foraging along Great Lakes beaches when they make their wintertime peregrinations down to our latitude, they certainly consume a lot of purple sand grass fruit as well as the seeds of other beach plants. And thus, these beautiful sparrows undoubtedly become important agents of dispersal for these plants. A percentage of plant fruit will pass through a bird's digestive tract intact and be expelled, possibly a far distance from where the fruit was eaten. Over the long haul, it is probably birds that are responsible for many plant species' distribution. I believe that sparrows, in particular, are important agents of dispersal for numerous grasses and sedges. I wrote about another likely case of interesting Snow Bunting seed dispersal RIGHT HERE.

The nearest breeding Snow Buntings to Ohio and Lake Erie are some 2,000 miles to our north. I took the photo above last June, showing a male Snow Bunting in his stunning breeding plumage in the barren rocky scree of St. Paul Island in the Pribilof Islands. This chain of volcanic islands is located near the middle of the brutal Bering Sea, several hundred miles west of mainland Alaska. It was a treat to see these birds that I know so well from their wintering grounds, on their nesting grounds. St. Paul Island would be charitably described as a barren place by most people, and the Snow Buntings seek out the bleakest haunts in this lunar landscape.

Fog enshrouds Snow Bunting nesting grounds on St. Paul Island. While most people would think this a harsh place, and rightfully so, the little buntings thrive here. The larking male buntings brought brightness and light to the misty barrens with their rich musical finchlike bubblings. Eternal optimists, the males return weeks in advance of females, and will routinely endure temperatures that plummet far below zero.

To them, the winter beaches of a place such as Lake Erie represents a balmy Floridian vacation.

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Tuesday, November 8, 2011

Meadowhawks

The last dragonflies to be on the wing, at least in appreciable numbers, are the meadowhawks. And of the eight Sympetrum meadowhawk species that have been found in Ohio, the one above is the hardiest of the lot. It is the autumn meadowhawk (formerly yellow-legged meadowhawk), Sympetrum vicinum. I made the photos above and below yesterday while on a lunchtime stroll around the grounds where my office is located.

Male meadowhawks are striking animals. The cherry-red abdomen is a conspicuous feature, but these are small dragonflies and often dart away with such rapidity that an average hiker may not see them well enough to appreciate their fiery tones. Separating the various species can also constitute an issue of identification, especially with the females. Males are easier, and two of the features to look for on autumn meadowhawk is the blood-red face and the pale straw-colored legs.

It's routine to see autumn meadowhawks on the wing in November, and I've even seen them out and about on cool blustery days with temperatures in the 50's. Yesterday and today was nice, sunny, and in the 60's and the meadowhawks were quite active.

This meadowhawk is a much rarer insect than the species above, at least in these parts. Or at least I think  it is. It is a blue-faced meadowhawk, Sympetrum ambiguum, and this specimen was the first one that I had seen. I found it back on September 5th in Green Lawn Cemetery in Columbus. The animal was wary and hard to approach, and would only alight on the lawn, so it made for tough photos. Note its beautiful bluish-white face.

There is a small pond not far from where I observed this blue-faced meadowhawk, and perhaps they use it as breeding habitat. Or it could be that blue-faced meadowhawks wander as do some of the other dragonfly species, and this individual had come from some distance away. Green Lawn Cemetery is an oasis of greenery in a sea of heavily urbanized cityscape, and attracts large numbers of migrant birds and other flighted organisms.

Here's the range map depicting the Ohio distribution for blue-faced meadowhawk, courtesy the Ohio Odonata Society. Records in RED are pre-1950 reports, as is the case with Franklin County, which is where I made the photo above. So unless I've muffed the identification, there is now a modern record of blue-faced meadowhawk for Franklin County.

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Monday, November 7, 2011

Interesting Bonaparte's Gull feeding strategy

Five hundred feet over Lake Erie and looking due south to the mouth of the Huron River at Huron, Ohio. I took this photo about two years ago, during a survey flight to document waterbirds on the lake. Nickel Plate Beach, where I made the Bonaparte's Gull photos that accompanied the preceding post, is the snow-covered bare patch on the photo's upper left corner.

A few hours after I made yesterday's blog entry about Bonaparte's Gulls, Doug Overacker made an interesting post on the Ohio Birds Listserv, as follows:

"Julie Karlson and I stopped near the Corps of Engineers Visitor Center at Buck Creek State Park this morning to scan the lake for waterbirds. I started scanning the lake and spotted some Horned Grebes. A Bonaparte's Gull was there with them. I scanned some more and found another Horned Grebe also accompanied by a Bonaparte's Gull. Then I found a Pied-billed Grebe and it was also accompanied by a Bonaparte's Gull. I watched the grebe dive and the gull flew. Soon the grebe came up and the gull landed right next to it. Again the grebe dove and the gull flew only to land next to the grebe when it came up. It repeated this one more time while I watched. My guess is that if any of the grebes came up with a small fish the gull would try to claim it. Are there any other explanations?"


Common Loon in basic plumage, Lake Erie. Photo courtesy Ernie Cornelius.

Doug's observation is an interesting one, and a phenomenon that I have observed dozens of times. During our Lake Erie surveys, we would fly at an altitude of 200 feet, and follow rigid transect lines that criss-cross the lake. Such a perspective offers a magnificent study of huge swaths of Lake Erie, and a unique angle on its bird life. During late fall surveys, we would encounter as many as several hundred loons resting or feeding far out on the lake. It wasn't long before we noticed that actively diving and feeding Common Loons would usually be attended by small squadrons of Bonaparte's Gulls, anywhere from a few birds to a dozen or more. Indeed, we quickly learned that we could spot feeding loons from far away by the concentrated little clouds of Bonaparte's Gulls. This was most helpful as things happen quickly in a fast-moving airplane and the gulls put us on alert to be prepared for loons.

As with all photos on this blog, you can click the photo to expand it. This photo and the next are not great, but I took them in flight as we passed over loons being attended by Bonaparte's Gulls. In the photo above, the loon is easy to see as the big brown surfaced submarine of a bird. A few gulls are hanging with it waiting for some action.

What sort of action? Gulls are well known kleptoparasites, a term that refers to thievery. It is applied to gulls, jaegers, and other creatures that routinely steal food from another animal. We've probably all seen gulls harassing some hapless tern until it disgorges its catch, which the gull then snaps up and swallows. That's kleptoparasitism.

When we first observed the loon-Bonaparte's Gull interaction, we assumed we were witnessing a case of kleptoparasitism. The loon would surface, and the gulls would attempt to snatch its fish away. Except that it became apparent that the gulls never made contact with the loon - and a Common Loon outweighs a Bonaparte's Gull by 21 times. Rather, the surfacing of the loon would send the pack of gulls into a frenzy and they would alight and dip at the water's surface in the immediate vicinity of the just-surfaced loon.

This photo shows a small mob of Bonaparte's Gulls in a frenzy induced by a surfacing Common Loon. What it turns out is happening is that the loons, obviously, are hunting over schools of small fish. It seems that the entrance of a large fast-swimming underwater avian predator throws the fish into a panic, and small fry such as emerald shiners are flushed to the surface. The gulls have learned this, and are poised and ready to attack the fish that arise along with the loon. Such a relationship is known as commensalism: one species benefits from an interaction while the other is unaffected.

I plumbed the literature to see if anything had been published specific to commensalism involving Bonaparte's Gulls and loons or other diving waterbirds, and sure enough, there are a few snippets of information out there. The Birds of North America account of Bonaparte's Gull has this to say:

"Also forage in association with Hooded Mergansers (Lophodytes cucullatus) and Red-breasted Mergansers (Stedman and Stedman 1989), Common Loons (Gavia immer; Svingen 1999, JB), Double-crested Cormorants (JB, MG), Horned Grebes (Podiceps auritus; Dusi 1968), Red-necked Grebes (P. grisegena; Svingen 1999), and Brown Pelicans (Pelecanus occidentalis; Cruickshank and Cruickshank 1958). Bonaparte’s Gull often hovers over the feeding mergansers, cormorants, or grebes, dipping into the water to obtain small items, such as fish, forced up by the diving birds; also swims with loons and grebes, picking up small items from the surface. Feeding with these species is a form of social parasitism." (Burger, Joanna and Michael Gochfeld. 2002. Bonaparte's Gull (Chroicocephalus philadelphia), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/634)

A brief note from The Auk, Vol. 85: 1, 1968 is entitled Feeding interaction between Bonaparte's Gulls and Horned Grebes. It reads as follows:

Several times between 19 and 28 December 1966 at West Panama City Beach, Bay County, Florida, my wife and I saw Bonaparte's Gulls (Larus philadelphia) and Horned Grebes (Colymbus auritus) feeding together, the gulls eating food the grebes brought to the surface. The grebes fed leisurely about 150 feet offshore, usually in groups of three to six. Two to three times as many immature and adult Bonaparte's Gulls usually fed with them. As the grebes dived, the gulls swam or flew above them. When a grebe surfaced, a gull was usually at the spot for any bits of food it could salvage. We observed no physical contact between birds during these encounters. Neither A. C. Bent (U.S. Natl. Mus., Bull. 107, pp. 23-25, 1919, and Bull. 113, pp. 177-179, 1921) nor R. S. Palmer (Handbook of North American birds, vol. 1, New Haven, Yale Univ. Press, 1962; see p. 79) mention such associations between these species or between either of these species and other species.--Julian L. Dusi, Department of Zoology, Auburn University, Auburn, Alabama.

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