<u revel in the last few weeks of short-sleeves and sunshine, be sure to stroll through the Arb and appreciate the color and frenzy that accompanies this short-lived season. You won’t have to look very hard to find fall color: trees covered in the vibrant red vine Virginia creeper (Parthenocissus quinquefolia) are common along trails in the floodplain and oak savanna restorations in the lower Arb. As this perennial vine enters the over-wintering phase of its life-cycle, it is dependent upon migratory birds to disperse the seeds found in its grape-like berries. It is indeed the season of fruit and frugivore: highbush cranberry, elderberry, wild grape, and buckthorn fruits abound, supplying energy-rich sources of food for the thousands of songbirds that will pass through the Arb in the coming weeks.
If you manage to take your eyes off the electrifying foliage and are not too busy stuffing wild grapes into your mouth, you might notice tiny piles of purple “droppings” littering the trails. A close inspection of these piles reveals that they are seeds and skins of berries from nearby plants— all too often buckthorn—that were unable to pass through avian digestive tracts and thus were regurgitated. An abundance of these droppings can lead you to berry-rich areas, which are often prime spots for observing mixed-species foraging flocks.
If you find yourself in the midst of such a flock, don’t be discouraged by your inability to identify individual species. Many birds look very similar in the fall and winter months because they have recently lost their distinctive breeding plumage in favor of inconspicuous feathers. Even the most experienced ornithologists are often stumped by the infamous “fall warblers”—all various shades of grey, yellow and green and identifiable only by the most subtle variations, if at all.