Friday, August 28, 2009

Swift River Cruiser

Four Mile Creek in Butler County has some nice stretches that offer good public access. I've waded the creek a number of times, looking for mayfly nymphs, dragonflies, and whatever else might be in or near the water. Wednesday I caught, photographed, and released a female Swift River Cruiser (Macromia illinoiensis illinoiensis) that was ovipositing in a six-inch-deep section of pebbly riffles below the rapids created by a cement rip-rap pipeline crossing.

On most of my visits to this section of the creek, I've only seen single Swift River Cruisers, flying long routes up and down the creek a few inches above the water. These individuals have proven impossible to catch, and I gave up trying to catch flying adults and concentrated instead on trying to find larvae. I've yet to find a Swift River Cruiser larva, but I did manage to find a Flag-tailed Spinylegs (Dromogomphus spoliatus) larva last July.

Wednesday, there was a little more activity on the creek, with at least four Swift River Cruisers near the pipeline cut rapids at one time, including a pair that met over the water, formed a "wheel" and flew up into the trees along creek. There were some aggressive interactions (I assume between males), and the general activity made me think that perhaps I'd catch a distracted bug looking for a mate or dealing with others of its kind. Occasionally, I would see a pair of bright green eyes zipping toward me or the yellow "taillight" as one flew past the other way. They have a maddening ability to disappear among the shallow rapids and then reappear sometimes right next to you before disappearing again.

I hadn't had any luck netting a river cruiser, and had given up for the day, when I saw an ovipositing female. I caught her while she was occupied. Once released, she returned to the riffles and continued laying eggs.

Female Swift River Cruiser (Macromia illinoiensis illinoiensis)
August 26, 2009. Four Mile Creek, Butler County, Ohio.

Friday, August 7, 2009

Trilobites, II


Except for the disarticulated trilobite exoskeletons, the other fossils depicted here come from ones my daughters and I have collected over the past few years. (Click on the image to see a larger version). The cephalopod chunk is about 5 inches or 11 centimeters long, and comes from a local creek. There's a clear C-shaped band of what might be silica crystals in the narrower, broken end of the fossil. The horn coral is a beautiful little fossil RJS found in Four Mile Creek last summer.

"Slab with slightly disarticulated trilobite exoskeletons . . . " is a companion to "Trilobite Concealed/Revealed." That piece is modeled after a 3 centimeter, 1-1/2 inch long trilobite fossil almost completely obscured in a stone I found last summer in a little wildcat gravel mining site along the Great Miami River.

Feldmann, et. al.'s Fossils of Ohio (Bulletin 70, Ohio Division of Geological Survey, Columbus, Ohio. 1996), is a handy reference when messing around with fossils.

This piece uses the font Arial, which many consider the evil second-rate impostor of perhaps the most ubiquitous and, in the eyes of many designers, the worst font in the world (besides Arial):Helvetica. (In 2007, Helvetica was the subject of a documentary that has appeared on PBS, among other places. Excerpts can be viewed on YouTube.)

Tuesday, August 4, 2009

Phantom Crane Fly



This piece is based on a photo of a Phantom Crane Fly taken by William Hull at a sphagnum bog at the base of an old sandstone quarry in Pike County, Ohio (If you click on the image, it should come up full-size). At some point, a portion of the quarry site was colonized by sphagnum. A number of other interesting plants and animals have followed over the years, including a nice array of different species of beetles, damselflies, and dragonflies, among many others, and, of course, the Phantom Crane Fly, Bittacomorpha clavipes. The black and white markings on this particular species make it seem as if the insect is flickering as it helicopters and floats about the vegetation. Here, it's momentarly hanging on a sedge.

Bogs are rare treasures in Ohio. Here's a link to a paper titled Development of a Sphagnum Bog on the Floor of a Sandstone Quarry in Northeastern Ohio, which discusses the formation and composition of a bog in Portage County that possibly developed in a manner similar to the Pike County site.

There are a number of interesting photos at William Hull's website, www.mangoverde.com, including a large and excellent collection of photographs of birds, butterflies, dragonflies, and damselflies by Hull and other contributors. One can spend a lot of time studying the critter photos on the mangoverde.com site.

Monday, August 3, 2009

Bad Photos of Ugly Birds, Part IV

The breeding chronology of Bobolinks is well known. Bobolinks are polygynous. They are also single brooded. Nesting typically begins in mid- to late-May, and the first young fledge as early as late-June and early July, with additional young fledging into late-July and August. As the young fledge, freeing adults from much of their parental duties, adult Bobolinks begin a complete molt. It’s also at this time that adults of both sexes and young form pre-migration flocks. They begin to migrate shortly thereafter.

There are numerous late-summer and fall reports of Bobolinks massing in coastal marshes in the east, as well as in interior marshes. These accounts usually note that Bobolinks travel to such sites after breeding in order to molt. (For a list of sources about Bobolinks, some of which were used in this series of posts, please see Part III.)

Perhaps because there aren't any particularly large marshes or wetlands near the VOA or because of some other reason, Bobolinks at this site seem to complete or nearly complete their molt from alternate to basic plumage before departing, usually around mid- to late-August.

Migrating fall Bobolinks occasionally are reported in large numbers in nearby locales such as Miami-Whitewater Wetlands, a mixed wetland/prairie site in northwestern Hamilton County. In Ohio, there are historic and more recent records of migratory Bobolink flocks numbering in the hundreds, and more rarely thousands, in Lake Erie marshes as well as in grasslands and reclaimed strip mines in northeastern and central Ohio. I assume most of the birds are in basic plumage, since there don't seem to be any reports of large numbers of migratory Bobolinks still deep in their molt or arriving at these stop-over sites in alternate or near alternate plumage, which would indicate that molt was yet to start or perhaps suspended. Indeed, since Bobolinks usually undergo rapid loss of tail and wing feathers early in their molt, it's not likely that birds in such condition will purposely fly very far.

Since the birds at the VOA are usually well into their molts by mid- to late-July, I've assumed that the majority of them are molting on site, as opposed to making a "molt migration" to a non-breeding site such as a marsh or different grassland and beginning their molt there.

What I was never able to figure out at the VOA is how many, if any, migrating Bobolinks from other breeding sites drop into the VOA during their migration. I assume some birds outside of the VOA breeders find the site each summer.

To (finally) conclude this series of posts and their use of golden oldie photos, here is a gallery of sorts of molting Bobolinks. All photos were taken in the summer of 2004 at the VOA:


(Female. 11 July 2004)

(Female. 1 August 2004. This bird is just beginning its molt--almost a month after many of the males had begun their molt.)


(Female. New tail feathers coming in. 18 July 2004.)



(Two views of the same hatch-year bird in juvenal plumage. 3 July 2004.)


(Adult Bobolink, basic plumage. The fresh tail eathers have a softer or more rounded appearance compared to the "pointy-tipped" feathers of the hatch-year bird in the photo from the same date, below. 12 August 2004.)

(Probable hatch-year Bobolink. Points in favor: the tail feathers are more pointed than the adult in the photo above. The tertials are a little worn, too. The plumage seems "complete" with no noticeable gaps in flight feathers, coverts, tertials, etc. That is, there doesn't seem to be any clear sign that this bird is still molting, and by the date, and given that the other adult birds on site were mostly in complete or near-complete basic plumage, this should be a hatch-year bird. Where's a bander when you need one? Problem solved if the bird is in hand! 12 August 2004.)

(Adult Bobolink, sex unknown, possibly female given the early date? Coverts and wings showing signs of molt. Compare to Hatch-year Bobolink photos above and in Parts II and III. 11 July 2004)