Each spring and fall, Purple Finches are regular migrants through the Lower Susquehanna River Watershed. Northbound movements usually peak in April and early May. During the summer, these birds nest primarily in cool coniferous forests to our north. Then, in October and November each year, they make another local appearance on their way to wintering grounds in the southeastern United States. A significant population of Purple Finches remains to our north through the colder months, inhabiting spruce-pine and mixed forests from the Great Lakes east through New England and southeastern Canada. This population can be irruptive, moving south in conspicuous numbers to escape inclement weather, food shortages, and other environmental conditions. Every few years, these irruptive birds can be found visiting suburbs, parks, and feeding stations—sometimes lingering in areas not often visited by Purple Finches. Right now, Purple Finches in flocks larger than those that moved through earlier in the fall are being seen throughout the lower Susquehanna valley. Snow and blustery weather to our north may be prompting these birds to shift south for a visit. Here are some looks at members of a gathering of more than four dozen Purple Finches we’ve been watching in Lebanon County this month…
Purple Finches are easily distinguished from House Finches by their notched tails, darker streaking, and well-defined facial markings. Though most frequently found in proximity to conifers, they also visit native deciduous trees and shrubs to snack on berries, seeds, and buds. Purple Finches can be particularly fond of maple, birch, poplar, sumac, and viburnum.Adult male Purple Finches are unmistakable in their wine-colored plumage.Purple Finches join a Dark-eyed Junco, a White-throated Sparrow, and a Black-capped Chickadee at a feeding station.Purple Finches eating black oil sunflower seed.A male Purple Finch in successional forest edge habitat consumes seeds from a dried stand of goldenrod.Purple Finches with juncos and Northern Cardinals.Purple Finches filling up on supplemental foods.
As the autumn bird migration draws to a close for 2024, we’re delighted to be finding five of our favorite visitors from the coniferous and mixed forests of Canada and the northernmost continental United States.
Yellow-bellied Sapsuckers drill evenly spaced holes which they repeatedly visit to harvest “sap” and the insects that become trapped therein. These surgically small excavations penetrate only the bark and the phloem, a shallow, spongy layer of the trunk that carries sugars from the leaves to other parts of the tree. Seldom do they puncture the thin, underlying cambium layer which protects the true sapwood. After healing, sapsucker holes leave linear rows of small scars which are sometimes still discernible decades after a bird’s final visit. This adult male will probably linger in the Lower Susquehanna River Watershed until colder weather renders the tree totally dormant, the flow of “sap” ebbs, and small insects become harder to find. Then he’ll make his way off toward southern forests of oak and pine for the remainder of the winter. Sapsuckers work their way north as sugary “sap” begins flowing again in the spring.The Hermit Thrush is another denizen of coniferous and mixed forests. In habitats with dense cover and sufficient food sources like fruit-bearing shrubs and vines, some will remain through the winter. The Hermit Thrush is the only spot-breasted thrush regularly seen in our region from November through March.Almost the size of a thrush, the largest of our native sparrows, the Fox Sparrow, is currently at the peak of its southbound migration. While taking a break from their nocturnal flights, some may stray from forest edges to visit suburban feeding stations. Most leave our area by mid-December, then begin returning north as early as mid-February.Not present every year, flocks of Pine Siskins are beginning to arrive in the lower Susquehanna region. They are currently most common along the mountain tops of the Ridge and Valley Province where they are feeding on the seeds of the Sweet Birch, a tree also known as Black Birch. Look for them around niger seed feeders and on the prickly seed balls of cultivated American Sweetgum, but don’t be surprised if they quickly pass us by to spend the winter on the Atlantic Coastal Plain to our south where this native tree grows in abundance.Since late October, Purple Finches have been widespread throughout the region. These female/juvenile male types are frequently being seen at feeders, particularly near woodlands and other areas with stands of conifers.Less frequently seen are the adult male Purple Finches in their raspberry-colored plumage. What a dandy.
While right now is the best time to get out and look for these species from the northern forests, any or all of them could linger into the winter months, particularly where the food supply is sufficient and conifers and other evergreens provide cover from the blustery weather.
Our cute lovable chickadees are resident birds, remaining in the same general area throughout the year, often throughout their lives. In the Mid-Atlantic States, there are two species. The tiny Carolina Chickadee is at the northern limit of its geographic range in the Piedmont Province of southcentral Pennsylvania. The slightly larger Black-capped Chickadee is a year-round resident mostly to the north of the Lower Susquehanna River Watershed. Within the Susquehanna basin, an intergrade zone of the two species occurs in the mountains and bottomlands of the southern portion of the Ridge and Valley Province just to the north of the Pennsylvania cities of Carlisle, Harrisburg, and Lebanon. The range of the Carolina Chickadee, as well as the hybrid zone, has gradually crept north during the last fifty years—as much as twenty or thirty miles—while the range of the pure-bred Black-capped Chickadee has simultaneously withdrawn almost entirely from the lower Susquehanna, particularly in the valleys.
Every few years, presumably when their numbers are too great for the sustenance available from the wild food crop in their home range, Black-capped Chickadees invade the more southerly range of both Carolina Chickadees and the hybrids in the intergrade zone. This appears to be one of those years. Black-capped Chickadees are working their way south and showing up at feeding stations stocked with sunflower seeds, safflower seeds, and/or peanuts—sometimes in flocks numbering five to ten birds or more.
Let’s take a closer look at the two species…
In the Lower Susquehanna River Watershed from the Great Valley (Cumberland/Lebanon Valley) south into Maryland, the Carolina Chickadee is the resident species of “tit”.The Black-capped Chickadee, usually a resident of highlands to the north of the lower Susquehanna valley, is slightly larger than the Carolina Chickadee. The most conspicuous difference is the extensive amount of white in the “black-cap’s” wings, both on the edges of the flight feathers and on the set of coverts at the “shoulder”. Black-capped Chickadees often appear longer tailed and bigger headed than Carolina Chickadees and the edge of the black bib is often more ragged. The buffy wash on the flanks is usually more noticeable on the Black-capped Chickadee than on a Carolina. Hybrids from the intergrade zone, having a varying blend of characteristics, are more difficult to identify.
Not only is now a good time to carefully check the chickadees you see, but it’s an opportune time to watch for other invaders from the north, specifically the “winter fiches” including Pine Siskins, Evening Grosbeaks, Purple Finches, Red Crossbills (Loxia curvirostra), and White-winged Crossbills (Loxia leucoptera). During recent weeks, each of these species has been reported by observers at hawk-counting stations on local ridgetops, an indication that they too are experiencing inadequate food resources in their home ranges.
So, as winter approaches, you’ll want to keep an eye on those feeders—and don’t forget to keep an ear on the pines and hemlocks. The rewards could be many!
White-winged Crossbills during an invasion of the lower Susquehanna region in February 2009. Previously unnoticed in the shade, the sounds of their bills crunching the cones led to the discovery of this female (left) and male (right) among a small flock of six crossbills found feeding on Eastern Hemlock seeds at ground level.
It seems a bit early, but Purple Finches are indeed beginning to transit the Lower Susquehanna River Watershed on their way south. This one is feeding on the abundance of seeds produced by a Green Ash that has, at least thus far, survived the Emerald Ash Borer invasion.
Thoughts of October in the Lower Susquehanna River Watershed bring to mind scenes of brilliant fall foliage adorning wooded hillsides and stream courses, frosty mornings bringing an end to the growing season, and geese and other birds flying south for the winter.
The autumn migration of birds spans a period equaling nearly half the calendar year. Shorebirds and Neotropical perching birds begin moving through as early as late July, just as daylight hours begin decreasing during the weeks following their peak at summer solstice in late June. During the darkest days of the year, those surrounding winter solstice in late December, the last of the southbound migrants, including some hawks, eagles, waterfowl, and gulls, may still be on the move.
The Rough-legged Hawk (Buteo lagopus), a rodent-eating raptor of tundra, grassland, and marsh, is rare as a migrant and winter resident in the lower Susquehanna valley. It may arrive as late as January, if at all.
During October, there is a distinct change in the list of species an observer might find migrating through the lower Susquehanna valley. Reduced hours of daylight and plunges in temperatures—particularly frost and freeze events—impact the food sources available to birds. It is during October that we say goodbye to the Neotropical migrants and hello to those more hardy species that spend their winters in temperate climates like ours.
During several of the first days of October, two hundred Chimney Swifts remained in this roost until temperatures warmed from the low forties at daybreak to the upper fifties at mid-morning; then, at last, the flock ventured out in search of flying insects. When a population of birds loses its food supply or is unable to access it, that population must relocate or perish. Like other insectivorous birds, these swifts must move to warmer climes to be assured a sustained supply of the flying bugs they need to survive. Due to their specialized food source, they can be considered “specialist” feeders in comparison to species with more varied diets, the “generalists”. After returning to this chimney every evening for nearly two months, the swifts departed this roost on October 5 and did not return.A Northern Parula lingers as an October migrant along the Susquehanna. This and other specialist feeders that survive almost entirely on insects found in the forest canopy are largely south of the Susquehanna watershed by the second week of October.The Blackpoll Warbler is among the last of the insectivorous Neotropical warblers to pass through the riparian forests of the lower Susquehanna valley each fall. Through at least mid-October, it is regularly seen searching for crawling insects and larvae among the foliage and bark of Northern Hackberry (Celtis occidentalis) trees near Conewago Falls. Most other warblers, particularly those that feed largely upon flying insects, are, by then, already gone.The Blue-headed Vireo, another insectivore, is the last of the vireo species to pass through the valley. They linger only as long as there are leaves on the trees in which they feed.Brown Creepers begin arriving in early October. They are specialist feeders, well-adapted to finding insect larvae and other invertebrates among the ridges and peeling bark of trees like this hackberry, even through the winter months.Ruby-crowned Kinglets can be abundant migrants in October. They will often behave like cute little flycatchers, but quickly transition to picking insects and other invertebrates from foliage and bark as the weather turns frosty. Some may spend the winter here, particularly in the vicinity of stands of pines, which provide cover and some thermal protection during storms and bitter cold.Beginning in early October, Golden-crowned Kinglets can be seen searching the forest wood for tiny invertebrates. They are the most commonly encountered kinglet in winter.The Yellow-bellied Sapsucker, a woodpecker, is an October migrant that specializes in attracting small insects to tiny seeps of sap it creates by punching horizontal rows of shallow holes through the tree bark. Some remain for winter.The Yellow-rumped Warbler arrives in force during October. It is the most likely of the warblers to be found here in winter. Yellow-rumped Warblers are generalists, feeding upon insects during the warmer months, but able to survive on berries and other foods in late fall and winter. Wild foods like these Poison Ivy berries are crucial for the survival of this and many other generalists.American Robins are most familiar as hunters of earthworms on the suburban lawn, but they are generalist feeders that rely upon fruits like these Eastern Red Cedar (Juniperus virginiana) berries during their southbound migration in late October and early November each year. Robins remain for the winter in areas of the lower Susquehanna valley with ample berries for food and groves of mature pines for roosting.Like other brown woodland thrushes, the Hermit Thrush (Catharus guttatus) is commonly seen scratching through organic matter on the moist forest floor in search of invertebrates. Unlike the other species, it is a cold-hardy generalist feeder, often seen eating berries during the southbound October migration. Small numbers of Hermit Thrushes spend the winter in the lower Susquehanna valley, particularly in habitats with a mix of wild foods.Due to their feeding behavior, Cedar Waxwings can easily be mistaken for flycatchers during the nesting season, but by October they’ve transitioned to voracious consumers of small wild fruits. During the remainder of the year, flocks of waxwings wander widely in search of foods like this Fox Grape (Vitis labrusca). An abundance of cedar, holly, Poison Ivy, hackberry, bittersweet , hawthorn, wild grape, and other berries is essential to their survival during the colder months.Red-breasted Nuthatches have moved south in large numbers during the fall of 2020. They were particularly common in the lower Susquehanna region during mid-October. Red-breasted Nuthatches can feed on invertebrates during warm weather, but get forced south from Canada in droves when the cone crops on coniferous trees fail to provide an adequate supply of seeds for the colder fall and winter seasons. In the absence of wild foods, these generalists will visit feeding stations stocked with suet and other provisions.Purple Finches (Haemorhous purpureus) were unusually common as October migrants in 2020. They are often considered seed eaters during cold weather, but will readily consume small fruits like these berries on an invasive Mile-a-minute Weed (Persicaria perfoliata) vine. Purple Finches are quite fond of sunflower seeds at feeding stations, but often shy away if aggressive House Sparrows or House Finches are present.
The need for food and cover is critical for the survival of wildlife during the colder months. If you are a property steward, think about providing places for wildlife in the landscape. Mow less. Plant trees, particularly evergreens. Thickets are good—plant or protect fruit-bearing vines and shrubs, and allow herbaceous native plants to flower and produce seed. And if you’re putting out provisions for songbirds, keep the feeders clean. Remember, even small yards and gardens can provide a life-saving oasis for migrating and wintering birds. With a larger parcel of land, you can do even more.
GOT BERRIES? Common Winterbery (Ilex verticillata) is a native deciduous holly that looks its best in the winter, especially with snow on the ground. It’s slow-growing, and never needs pruning. Birds including bluebirds love the berries and you can plant it in wet ground, even along a stream, in a stormwater basin, or in a rain garden where your downspouts discharge. Because it’s a holly, you’ll need to plant a male and a female to get the berries. Full sun produces the best crop. Fall is a great time to plant, and many garden centers that sell holiday greenery still have winterberry shrubs for sale in November and December. Put a clump of these beauties in your landscape. Gorgeous!
