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Week One AND Week Two of our annual
Hummingbird Expeditions to Costa Rica
are filled. Please let us know if you'd like to be placed on the wait list. (Or, if you have several people lined up, we'll add another week!)

Even though winter isn't official until December's solstice, November just about brings an end to autumn here in the Carolina Piedmont. Nearly all our Neotropical avifauna have departed for locations closer to the equator while winter resident birds have begun to arrive in good numbers from New England and Canada. Tree leaves are at their colorful prime and the vast majority of flowering plants have replaced their blossoms with some sort of seed. Outdoor temperatures are notoriously unpredictable at this time of year, with overnight lows near freezing giving way to daytime temps in the 80s--making it difficult to know whether to load the wood stove or turn on the air conditioner. Yes, it's an interesting time for the nature observer, a time when we're alternately surprised by things unusual and reassured by others that are commonplace. Expecting both the expected and the unexpected, this week we explored Hilton Pond Center to see just what we could find during what we're calling our "Final Fall Fling" of 2007.

All text & photos © Hilton Pond Center

Speaking of migrant birds . . . one sure sign summer is gone, fall has come, and winter is soon on the way is the overnight appearance around Hilton Pond of a drab-colored warbler. The little bird in question has dull brownish-gray on its back, shows dark streaking on an otherwise light breast, sports two white bars per blue-black wing, and bears a thin white eye ring. Most of our breeding and Neotropical warblers disappeared weeks ago, but this newly arrived species began replacing them in mid-October and will hang around all winter, occasionally flashing one other field mark that is a giveaway identification hint: A bright yellow spot at the base of its tail (above). We speak, of course, of the Yellow-rumped Warbler--previously known as Myrtle Warbler and referred to by many birders by the perfectly picturesque nickname of "Butter-butt." Yellow-rumps nest in coniferous forests in the very northern contiguous states and all across Canada into Alaska, but they pretty much take over the warbler niche along the Eastern Seaboard during winter. Here at Hilton Pond Center, yellow-rumps are drawn irresistibly to an artificial water garden beside our old farmhouse, where they bathe in the shallows and likely look for insects or--when it really gets cold--seeds and berries.

We always expect Yellow-rumped Warblers in November--even though they appear some years in much smaller numbers--but there's one bird that never fails to delight and surprise us when it shows up in winter at the Center. We're surprised because this bird is a vireo, and vireos--like most warblers--are generally considered to be cold-weather wimps that must wing their way to tropical climes before our first frost hits. This week's remaining vireo (above) is the Blue-headed, which seems undeterred by plummeting temperatures. A few hang around most winters and on 7 November we managed to net one--a mildly painful reminder that this species is particularly feisty in the hand and has a little hook on the end of its bill. The bird we caught this week was only our 18th of its kind banded at the Center in 25 years. Incidentally, Blue-headed Vireos were split from the Solitary Vireo group when ornithologists determined they and Plumbeous and Cassin's Vireos were all distinct species.

Although most flowering plants have given up trying to blossom, we did manage to find a few asters in bloom at Hilton Pond Center. These qualify as DWCs--"darned white composites" the botanists call them, mostly because so many are similar and thus are difficult to identify to species. (Those in our photo above look a lot like Daisy Fleabane, but we're almost certain they're not.) Composite flowers are actually made up of TWO flower types: Sterile "ray flowers" (white in this case), and the central yellow "disc flowers" that actually produce seeds. The ray flowers--glowing brightly in the November sun--serve to attract the attention of whatever bees, wasps, flies, and other little nectar-loving pollinators might still be flying. Considering that it's November, we have an idea these particular asters--clustered beside some scary-looking blackberry thorns--might wither without achieving their pollination goals.

One of the most fascinating aspects of autumn at Hilton Pond Center is discovering the great diversity of ways our more ephemeral plants guarantee their genes are carried on to a new generation. For example, Anglepod, Gonolobus suberosus--a member of the Milkweed Family--twines its way along the ground and into small shrubs, producing five-inch heart-shaped leaves that turn bright yellow in fall. Its flowers--which smell like carrion--attract flies that bumble around, fertilizing its flowers. By November, the successful Anglepod blossom produces a large green seed pod (above) that gives the vine its common name.

All the milkweeds produce some sort of pod, and the Swamp Milkweed, Asclepias incarnata, is no exception. These days we have a couple of fast-expanding colonies of this pink-flowered species along the banks of Hilton Pond. We didn't plant them, so we can only assume their fluffy seeds (above) blew onto the property on a gusty wind and found habitat to their liking. Swamp Milkweed's slender two-inch pods open much earlier in autumn than the big, fat four-inch fruits produced by Anglepod; the latter are still green and firm and we can't wait for them to open to reveal whether their seeds are just as hairy as those of Swamp Milkweed.

All flora have to find a way to propagate, and the so-called "primitive" plants are no exception. The sedges (Cyperaceae), mostly water-loving species that grow along streams and ponds, are ancient plants that superficially look like grasses but have distinctive triangular stems that set them apart. Sedge flowers aren't all that showy, but their fruit heads (above) still demonstrate just how diverse nature can be when it comes to making seeds. Sedges started appearing around Hilton Pond at about the same time as Swamp Milkweed, but without the latter's fuzzy parachutes sedge seeds may have required birds or small mammals for transport.

Like the Swamp Milkweed, sedges are relatively recent arrivals at Hilton Pond Center. Until 25 years ago previous property owners cut down all vegetation right down to water's edge, and that practice didn't allow for much riparian vegetation. These days the edge of Hilton Pond isn't even where it was six months ago; during the current drought the water level has dropped nearly four vertical feet and the surface area of the pond itself is at least 25% less than this time last year. All this means any sedges and milkweeds formerly on the banks of Hilton Pond are now up to 15 feet from the water, a location that may prove too dry for them to survive unless we get significant precipitation before the next growing season. One organism that has adapted nicely to low water levels is the Great Blue Heron, whose five-inch track (above) indicate it has found new hunting grounds in the now-exposed mud flats around the pond perimeter.

Yes, autumn brings all sorts of evidence that nature is changing drastically with the advent of cool weather. As we returned one afternoon this week from a bicycle ride through the colorful fall countryside, we slowed down near the driveway to Hilton Pond Center. There--crossing the road as we glided to a stop--was a big Chinese Mantid, Tenodera aridifolia sinensis. Lest it get run over by traffic bearing down on us from behind, we snatched the five-inch insect from the asphalt and turned into the drive. The mantid squirmed and squeezed tightly with heavily barbed forelegs; we were glad to be wearing bike gloves at the moment. A swelled abdomen on the praying mantis indicated it was a female laden with eggs, so we parked our bike, went into the Center's old farmhouse, and grabbed our camera, tripod, and close-up lens. Placing the mantid on a convenient tree branch, we snapped off a few shots of the insect's bulbous eyes (above) before she ambled off robotically, out of camera range. We're guessing this mantid will find a suitable twig on which to lay her egg mass and then go off to die, the ultimate end for what was truly her "Final Fall Fling."

All text & photos © Hilton Pond Center

Comments or questions about this week's installment?
Please send an E-mail message to INFO.

Be sure to scroll down for an account of all
birds banded or recaptured during the period,
plus other nature notes of interest.

Thanks to the following fine folks for recent gifts in support of Hilton Pond Center for Piedmont Natural History and/or Operation RubyThroat: The Hummingbird Project. Your tax-deductible contributions allow us to continue writing, photographing, and sharing "This Week at Hilton Pond." (Please see Support if you'd like to make a gift of your own.)

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