Saturday, October 29, 2011

Goldenrod Ball Galls -- © Dave Spier

Pair of ball galls on Canada Goldenrod stem at Montezuma Audubon Center - © Dave Spier

In August and early September, the field had been bright yellow with goldenrod flowers. Now it’s turning brown, although this too can be attractive when the plants are frosted and backlit by the rising sun. In November, most of the goldenrod leaves will shrivel and drop, exposing abnormal swellings on many of the plant stems. The common ones found on Canada Goldenrod are ball-shaped, resembling miniature basketballs about an inch or more in diameter. Not surprisingly they are usually called "goldenrod ball galls."

To fully understand galls we need to cut one open and look inside. Carefully pry and twist while cutting into the pithy core and try to pop the gall open. At the very center is a small cavity with the even smaller white larva of the peacock fly, Eurosta solidaginis, a relative of the fruit fly. Originally injected into the stem as an egg, it hatched and began feeding. Chemicals in its saliva stimulate the host plant to produce a pithy bulge in an effort to heal the "wound" caused by the parasitic larva. This actually benefits the insect by providing endless food and later an insulating shelter with a hard, weatherproof shell.

The gall, however, is not impermeable. Downy Woodpeckers and Black-capped Chickadees have learned that galls contain a nutritious morsel, and these birds will peck and chisel until they get it. You can recognize their work by the rough, funnel-shaped excavations they leave behind.

Gall fly larvae that escape this fate will chew a tunnel almost to the surface and there they will pupate until they emerge. Winged adults lack chewing mouth parts and can only pop the lid. They do this by inflating a balloon-like bladder (called the ptilinum) between the eyes. You can recognize their work by the small, sharp-edged hole that appears to have been drilled into the gall. The only function of the adult stage is to find a mate and lay more eggs in more goldenrod stems.

Goldenrods are prone to several other kinds of galls. An irregular-shaped growth called the "knotty goldenrod gall" is caused by the gall midge Lasioptera solidaginis. It’s somewhat globular, but not pith-filled. Less obvious is a long, spindle-shaped bulge called the "elliptical goldenrod gall" caused by the caterpillar of a moth.

A third type is very different in structure and occurs at the top of the stem. The "goldenrod bunch gall" is actually a globular head of deformed leaves about two inches in diameter. It is caused by a gall midge, a type of fly related to the mosquito. Its egg-laying apparatus, called an ovipositor isn’t strong enough to pierce the tough stem, so it contends with laying its egg on the tip of the plant.

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Thursday, October 27, 2011

Taughannock Falls

Mist spraying from the base of Taughannock Falls accents the footbridge near the end of the lower gorge trail - © Donna Mason-Spier
The highest waterfall in New York State is easily accessible off Rt. 89 northwest of Ithaca in Tompkins County. Taughannock Creek flows east and descends the valley slope to end in Cayuga Lake. Since the end of the last Ice Age, the creek, by utilizing two significant waterfalls, has cut an impressive gorge into the plateau. I suggest starting at the overlook on the north rim of the gorge about a half mile uphill from Rt. 89. Through a break in the forest, you gain an overview of the lower gorge below the main falls, plus a glimpse into the upper gorge above this falls.

Drive downhill and turn right (south) on Rt. 89, cross the creek and pull into the lower parking lot on your right. (If this lot is full, there are larger lots on the east side of Rt. 89, toward Taughannock Point, a delta created by the creek from sediments washed out of the hillside.) A three-quarter mile walking trail leads up the gorge through a mature forest to the base of 215' high Taughannock Falls. Yes, it's higher than Niagara, but of course it lacks the width and volume of water. (After all, Niagara drains the four upper Great Lakes on their way to Lake Ontario and then the St. Lawrence.)

The lower falls capped by Tully limestone - © Donna Mason-Spier
Even from the parking area, you can see the lowest falls, created by the resistant Tully limestone caprock. The weak Hamilton shales at the base of this falls are easily eroded with the result that blocks of limestone break off.  Both are members of the Catskill Delta created during the Devonian period.
 
Joints (tension cracks) crossing Tully limestone above lower falls - © Donna Mason-Spier
Above the lower falls, the creek has washed off the relatively flat surface of the Tully upstream to a wide "step" falls created by another layer of the limestone. Above that another flat surface continues upstream until you reach the black Geneseo shale.

Solution pits and minor joints in the surface of the Tully - © Donna Mason-Spier

Solution pits and a major joint in the surface of the Tully - © Donna Mason-Spier

The "step" falls formed by an upper stratum of Tully limestone - © Donna Mason-Spier

Black Geneseo shale beside the gorge trail - © Donna Mason-Spier
Further up the gorge you'll see the beige cliffs formed by more resistant Sherburne siltstone, a slightly younger rock overlying the Geneseo formation. Both are in the Genesee group.


When you reach the wide amphitheater surrounding the falls, the highest portion of the cliffs are Ithaca shale which begins about 25' above the crest of the falls. At this point the gorge is about 400' deep.

The amphitheater cut into Sherburne siltstone overlying dark Geneseo shale, both formations in the Genesee group - © Donna Mason-Spier

Collapsed pinnacle of Sherburne siltstone, the lighter strata above the dark Geneseo shale - © Donna Mason-Spier

Autumn foliage in the lower gorge, October 23, 2011 - © Donna Mason-Spier

Reflection of autumn foliage on Taughannock Creek, October 23, 2011 - © Donna Mason-Spier

Tree-lined Lower Gorge Trail - © Donna Mason-Spier
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Wednesday, October 19, 2011

Blue Jays -- © Dave Spier



How would you describe Blue Jays (Cyanocitta cristata)? Noisy? Large? Bullies? Beautiful? Depends what you're doing (or what they're doing), I suppose. If you're a hunter or wildlife photographer, jays announce your presence to the rest of the forest world. If you feed birds, do the jays unintentionally (or intentionally) scare smaller birds away? Or worse, does a blue jay ever attack or even eat a smaller bird?
Jays are corvids (members of the Corvid, or crow, family) and share many characteristics with cousin crow. They have sturdy, all-purpose bills and they eat whatever they can find, or sometimes catch. They're right at home at bird feeders eating sunflower seeds and suet, but their natural diet includes a lot of nuts. They depended on chestnuts before that tree species was wiped out by blight. Then they shifted entirely to acorns and beechnuts. Many of these are "stored" underground for winter retrieval, much the way squirrels hide food, and the forgotten nuts grow into new oaks and beech trees. A single jay can stash up to 5000 acorns in a season, an average of 110 per day. The acorns are carried in the beak, the equivalent of us carrying a coconut in our mouth. Smaller acorns are carried four or five at a time using the throat and mouth as well as the bill. Jays are credited with reintroducing chestnuts, oaks and beech to New York and northward after the retreat of the glacier at the end of the last Ice Age. At the other extreme, oaks are absent from the world wherever there are no species of jays.
Jays have been known to eat parts of roadkills, but this niche is filled more by their larger black relatives, the crows and ravens. In the spring, Blue Jays have a bad reputation for eating the eggs and nestlings of smaller bird species, another habit shared with crows. During the warmer months, they eat salamanders, tree frogs, small snakes, snails, spiders, many beetles, grasshoppers, caterpillars and other insects. In late summer and fall they eat berries, corn and small rodents. On an annual basis, their diet is 76% vegetarian, 23% insects and only one percent vertebrates.
Blue Jays are year-round residents even though they seem to disappear into the trees during breeding season. They become silent to avoid drawing attention to their nests and avoid the spotlight on themselves as they prey on other nests. They raise one brood a year in the North, but the clutches are larger than those of jays in the South which have time for two or three broods.
Fledgling Blue Jays are scruffy copies of their parents. Males and females have identical plumage and may tell each other apart by voice or behavior. Females tend to be smaller. Their predominantly blue color is an optical illusion. Unlike paint pigments, the blue is created by microscopic flakes of melanin on the feathers that reinforce the blue spectrum and interfere with other colors. The bright blue wings and long tail are decorated with black bars and patches of white feather tips. The back and crest are a uniform darker blue. A dark necklace encircles a dirty white face and throat. The breast is light gray and the belly is nearly white.
After nesting season, jays resume their role as town criers. In fall they gather into small flocks and some (more likely the youngsters) migrate south. The remaining birds concentrate around dependable feeders where they are usually the largest visitors. Only Mourning Doves and grackles are larger. The Red-bellied Woodpecker, being slightly shorter, comes close in size and Hairy Woodpeckers are close behind red-bellies.
Shrikes are listed in the field guides as shorter than Blue Jays, but apparently they're strong enough to tackle the jay. I received a report of a shrike attacking a Blue Jay in the woods and carrying the struggling prey 50 feet. The shrike then nailed the jay to the ground and they struggled again. The shrike took off with the Blue Jay still in its beak and flew another 50 feet before the jay managed to get away. Shrikes lack the strong talons of a hawk and are incapable of killing their prey on the first strike. Had the predator been an Accipiter, or bird hawk, the jay would have become an instant meal. A Cooper’s Hawk would have little trouble dispatching a jay.
European visitors are envious that the spectacular Blue Jay is a common yardbird here. Perhaps we should admire its beauty and overlook what some people consider its faults, its aggressive behavior exhibited primarily during nesting season.

For a discussion of Adirondack Blue Jays, see the Adirondack Naturalist blog.
Questions and corrections may be sent to northeastnaturalist@yahoo.com


Sunday, October 16, 2011

Virginia Creeper -- © Dave Spier

Virginia Creeper at Montezuma Audubon center, Savannah, NY - © Dave Spier
I had stopped to check a "birdy" looking thicket [a habitat likely to hold a variety of birds] on my way home. Chip calls sounded like a cardinal, but I wasn’t sure. As I scanned the bushes, a mockingbird flew in and began eating the Virginia Creeper berries. The loose clusters of dark bluish-black fruits resemble wild grapes, but the dark-pink stems serve as a warning to people. Beware – due to oxalic acid, they are poisonous and potentially fatal if you eat enough of them. Apparently they have no effect on birds which have very different digestive systems than humans. (Remember, birds evolved from – or at least with – dinosaurs.) I can't remember whether I found a cardinal.

Virginia Creeper (also called Woodbine and Five-leaved Ivy) is a common woody vine, especially in lowland swamps. The one feeding the mockingbird was growing in a buckthorn bush at the edge of a damp meadow beside the road.

Creeper vines are related to grapes, but the leaves are very different. They are divided into five coarsely toothed leaflets arranged in a radial (spoked) pattern from the main leaf stem. In late spring, insignificant pale or greenish flowers grow in irregular clusters and these become the fruits of fall. As the leaves turn color and drop off, the berries become easier to find. Because of the attractive bright red or burgundy foliage in the fall, this plant is sometimes grown as an ornamental. On the other hand, if trying to remove this plant from a building, cut the main stem at the ground and wait for the adhesive pads to die and lose their grip. Ripping it off too soon could damage the surface.

Both species of Virginia Creeper climb by means of forked tendrils. Parthenocissus quinquefolia has tiny suction-like disks on the end of each tendril; P. inserta does not.

Native Americans used parts of the plant to treat jaundice, gonorrhea, and diarrhea. Mixed with vinegar it was used for lockjaw and wounds. Given the poisonous nature of the plant, I assume they first thoroughly dried Woodbine to remove the oxalate crystals.

Questions and corrections may be sent to northeastnaturalist@yahoo.com 
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Saturday, October 15, 2011

Woolly Bears -- © Dave Spier

Woolly-bear caterpillar at Blue Cut Nature Center between Newark and Lyons in Wayne County, NY - © Dave Spier

When was the last time you remarked, “Oh, there goes an Isabella Tiger Moth”?  Probably never (unless you’re an entomologist).  The wings are yellow-brown with some small black dots and a few faint lines for camouflage.  When opened, the wings span two inches or less.  During the summer, these moths can be found in meadows and fields and along road edges, but I don’t remember ever seeing one.  Frankly, it never occurred to me to even look for them.  Part of the problem is that these moths are nocturnal; look for them around porch lights.  I think I’ll put it on my calendar of things-to-do for next summer.  I guarantee they’re here, whether or not I can actually find one.  How do I know?  Read on…
When was the last time you remarked, “Oh, there goes a Woolly Bear”?  Probably within recent memory, and some days, several times – depending on the weather.  These are the familiar bristly caterpillars with black on each end and orange in the middle.  I see them crossing roads and open hiking trails, wiggling through the grass, or trying to hide in my garage.
It’s said that the amount of black portends the severity of the coming winter, but actually it only indicates how close to full grown it is.  It will find a snug shelter and spend the winter in the larval (caterpillar) stage, and by producing a type of antifreeze [technically a cryo-protectant chemical] they can survive freezing to temperatures of -90 degrees Fahrenheit.  This is why we see them again in early spring on a warm day.  They complete their metamorphosis (change) and emerge as adult Isabella Tiger Moths starting in June.  Other members of the Tiger Moth family are more strikingly marked and attractive.  Some have black and beige wings and rouge accents on the body and these are the species that give the clan its family name.
Tiger Moths are capable of producing ultrasonic sounds above our hearing range.  These are used to attract mates and also to interfere with bats’ echo location and thereby avoid capture and consumption by the flying mammals.  Most moths are nocturnal and this could help explain why most of us have never seen the adult Woolly Bear, a.k.a. the Isabella Moth (Pyrrharctia isabella).

Questions, comments and suggestions may be sent to northeastnaturalist@yahoo.com  For more information on New York's butterflies and moths, please visit the D.E.C. website for a PDF copy of their flyer.