a bug, a bird and a vine
Sometimes the week’s adventures don’t offer an obvious theme to neatly tie them all together. Unlike the inhabitants of the meadow in my previous post, these three were seen in various places, and don’t seem to have much in common (other than being in our forest.) But they do share one attribute – they’re all travelers.
This red-eyed beauty is a time traveler, feeding quietly through the long years and resurfacing to a different world, in the same place. We’re now seeing a three-years-early emergence of 17 year Periodical Cicadas, Brood X. You may remember this brood from its last emergence in 2004. Not expected to emerge till 2021, but climate change has tricked them into thinking it’s time. And the birds are happy. A few days ago I watched several Red-bellied Woodpeckers plucking the hapless newly adult cicadas from tree trunks, and even snatching one in mid-air, Phoebe-style.
Their perfectly round emergence holes can be easily spotted under older trees, as can the rather creepy google-eyed dried husks that were their nymphal skins. (It’s a very distinct memory from childhood – my young naturalist’s mind found them creepy and fascinating by turns).Today I heard the grinding of Cicada chorus notes starting up, making it feel like the dog days of summer are here already.
At the base of big trees, it’s easy to observe their emergence and rapid metamorphosis to adults. These older trees have gradually built up a below ground population of larvae that drink sap from the roots.The nymph crawls up a tree trunk if possible, and splits down the back to reveal the soft, pale new adult. The greater the numbers that emerge at one time, the better chance that predators will be so glutted that some are left to mate.
Our next traveler definitely moves through space; as a Neotropical migrant it makes a long and perilous journey every spring and fall. This little female Common Yellowthroat’s travels almost ended for good when she hit the glass windows at the rear of the Louisville Nature Center.
This site is particularly dangerous to small birds – they see only the illusion of forest in the reflective glass, and fly headlong, usually to their deaths. This one was lucky; it must have been a glancing strike. Though dazed at first and clenching its left foot, it perked up within minutes and I released it to continue its morning forage for insects.
It’s hard to believe how tiny these neotropical warblers are, until you have one in your hand. Moving seasonally between Central and North America, most of them must embark on a 20 hour non-stop flight of as much as 650 miles, just to cross the Gulf of Mexico. The Common Yellowthroat skulks about in marches and tangled wet meadows, where you may hear the male’s “witchety-witchety-witchety” song.
Our last traveler did not get here by itself – it was assisted and welcomed by humans. Asiatic Bittersweet’s long and tangled(!) trajectory from novel horticultural planting to hated invasive is a familiar one. In our forest as elsewhere it’s a strangler; encircling mature trees, or even itself to in order to get to the top of the canopy.
It’s the prime directive of vines – climb to the sunlight to reproduce.
As do most of our worst invasives, it produces a berry reward of such magnitude that no frugivore bird can resist it. Introduced to the east coast in the 1860’s from Japan, the first wild escape of this vine was noted in 1910 – from there the chart of its population trajectory goes straight up.
Oriental Bittersweet displays it’s circular twining habit from the very start. In the pic above a young vine is exploring for a support with its fast-growing tip. Unlike vines with tendrils ( grapevine, etc.), bittersweet wraps it’s entire growing stem around an unlucky tree. The process is just starting in the pic below.
In addition to taking over huge stretches of woodland, Oriental bittersweet is eliminating our native bittersweet species in many places through a double strategy of competition and hybridization.
It’s hard not to admire invasive plants, and even ascribe human characteristics to them. Many well-behaved(?) native plants can go on a rampage in different circumstances. Our more assertive natives such as White Snakeroot and Black Locust are invasive trouble-makers in Asia, so there is some equity.