At Lake Redman just to the south of York, Pennsylvania, a draw down to provide drinking water to the city while maintenance is being performed on the dam at neighboring Lake Williams, York’s primary water source, has fortuitously coincided with autumn shorebird migration. Here’s a sample of the numerous sandpipers and plovers seen today on the mudflats that have been exposed at the southeast end of the lake…
Not photographed but present at Lake Redman were at least two additional species of shorebirds, Killdeer and Spotted Sandpiper—bringing the day’s tally to ten. Not bad for an inland location! It’s clearly evident that these waders overfly the lower Susquehanna valley in great numbers during migration and are in urgent need of undisturbed habitat for making stopovers to feed and rest so that they might improve their chances of surviving the long journey ahead of them. Mud is indeed a much needed refuge.
Your best bet for finding migrating shorebirds in the lower Susquehanna region is certainly a visit to a sandbar or mudflat in the river. The Conejohela Flats off Washington Boro just south of Columbia is a renowned location. Some man-made lakes including the one at Middle Creek Wildlife Management Area are purposely drawn down during the weeks of fall migration to provide exposed mud and silt for feeding and resting sandpipers and plovers. But with the Susquehanna running high due to recent rains and the cost of fuel trending high as well, maybe you want to stay closer to home to do your observing.
Fortunately for us, migratory shorebirds will drop in on almost any biologically active pool of shallow water and mud that they happen to find. This includes flooded portions of fields, construction sites, and especially stormwater retention basins. We stopped by a new basin just west of Hershey, Pennsylvania, and found more than two dozen shorebirds feeding and loafing there. We took each of these photographs from the sidewalk paralleling the south shore of the pool, thus never flushing or disturbing a single bird.
So don’t just drive by those big puddles, stop and have a look. You never know what you might find.
Have you purchased your 2023-2024 Federal Duck Stamp? Nearly every penny of the 25 dollars you spend for a duck stamp goes toward habitat acquisition and improvements for waterfowl and the hundreds of other animal species that use wetlands for breeding, feeding, and as migration stopover points. Duck stamps aren’t just for hunters, purchasers get free admission to National Wildlife Refuges all over the United States. So do something good for conservation—stop by your local post office and get your Federal Duck Stamp.
Still not convinced that a Federal Duck Stamp is worth the money? Well then, follow along as we take a photo tour of Bombay Hook National Wildlife Refuge. Numbers of southbound shorebirds are on the rise in the refuge’s saltwater marshes and freshwater pools, so we timed a visit earlier this week to coincide with a late-morning high tide.
As the tide recedes, shorebirds leave the freshwater pools to begin feeding on the vast mudflats exposed within the saltwater marshes. Most birds are far from view, but that won’t stop a dedicated observer from finding other spectacular creatures on the bay side of the tour route road.
No visit to Bombay Hook is complete without at least a quick loop through the upland habitats at the far end of the tour route.
We hope you’ve been convinced to visit Bombay Hook National Wildlife Refuge sometime soon. And we hope too that you’ll help fund additional conservation acquisitions and improvements by visiting your local post office and buying a Federal Duck Stamp.
Rain from the remnants of Hurricane/Tropical Storm Harvey ended just after daybreak this morning. Locally, the precipitation was mostly absorbed into the soil. There was little runoff and no flooding. The river level at Conewago Falls is presently as low as it has been all summer. Among the pools and rapids of the Pothole Rocks, numbers of migrating birds are building.
Mist and a low cloud ceiling created poor visibility while trying to see early morning birds, but they’re here. The warblers are moving south and a small wave of them was filtering through the foliage on the edge of the Riparian Woodlands. One must bend backwards to have a look, and most could not be identified due to the poor lighting in the crowns of the trees where they were zipping about. Five species of warblers and two species of vireos were discerned.
There are increasing concentrations of swallows feeding on insects over the falls. Hundreds were here today, mostly Tree Swallows (Tachycineta bicolor). Bank Swallows (Stelgidopteryx riparia) numbered in the hundreds, far below the thousands, often 10,000, which staged here for migration and peaked during the first week of September annually during the 1980s and 1990s. Their numbers have been falling steadily. Loss of nesting locations in embankments near water may be impacting the entire population. A reduction in the abundance of late-summer flying insects here on the lower Susquehanna River may be cause for them to abandon this area as a migration staging point.
Clear weather in the coming nights and days may get the migrants up and flying in large numbers. For those species headed to the tropics for winter, the time to get moving has arrived.
When we look at birds, we are fascinated by the unique structure and appearance of their feathers. They set birds apart from all other life forms on the planet. Feathers enable most birds to achieve a feat long envied by humans…flight. Birds on the wing awaken a curiosity in man. They are generally the largest animals one will see in the air. People want to know the name of a bird they see flying by, and want to know more about it. The method and style of bird flight can aid an observer who attempts to determine which of the world’s 10,000 bird species he or she is studying. Body shape and bird sounds often tell us a lot about the birds we encounter. But most often, we rely on the unique colors, patterns, and shapes of the feathers, the plumage, to identify the bird we are seeing.
To birds, feathers are survival. They are lightweight and strong to support the mechanics of flight. Feathers are superb insulators against the elements, and provide additional buoyancy for birds spending time on the water. For most birds, feathers provide a coloration and a texture similar to their surroundings, enabling them to hide from predators or to stalk prey. In the case of some species, extravagant showy plumage is acquired, at least during the breeding season, and often only by males, as a way to attract a mate, intimidate rivals, defend a territory, or lure an intruder away from a nest site. Because they become worn and damaged, all feathers are periodically molted and replaced by fresh plumage.
The feathers worn by a young bird leaving the nest are called the juvenile plumage. Typically, this is followed by a molt into a basic (non-breeding) plumage. The oft times extravagant breeding feathers are the result of a molt into an alternate (breeding) plumage.
While making field observations, the species, subspecies, gender, age, and other vital statistics of a bird can often by discerned easily by noting the plumage. In the case of some other birds, diligence, experience, research, and an exceptionally good look and/or a photograph may be required to interpret these particulars. In still other instances, a trained expert with a specimen in the hand is the only method of learning the bird’s identity and background.
The age at which birds acquire adult breeding and non-breeding plumages varies by species. Many juvenile birds resemble adults in basic (non-breeding) plumage as soon as they leave the nest. For these birds, there is little difference between their juvenile plumage and the appearance of the feathers which follow the molt into their first basic (non-breeding) plumage. Bird species which sexually mature within their first year may acquire their first basic (non-breeding) plumage before arrival of their first winter, followed by an alternate (breeding) plumage by their first spring. This is particularly true for smaller short-lived birds. Other species, normally larger long-lived ones, may experience a sequence of molts through multiple basic (non-breeding) plumages over a period of years prior to resembling an adult. Some of these species, such as eagles, retain their juvenile plumage for as long as a year before extensive molting into a first basic (non-breeding) plumage begins. Still others, including many gulls, attain a first-winter (formative) plumage prior to molting into their first basic (non-breeding) set of feathers. Sexual maturity and initiation of an annual molt to alternate (breeding) plumage, if there is one, may take as long as three to five years for these bigger birds.
For nearly all species of birds, the molts which produce basic (non-breeding) plumage occur on at least an annual basis and include a total replacement of feathers. This process renews worn and missing plumes including the flight feathers of the wings and tail. Any molt to alternate (breeding) plumage often excludes the replacement of the feathers of the wings and tail. There are many exceptions to these generalities.
The Juvenile and non-breeding (basic) plumages of late-summer may seem drab and confusing, but learning them is a worthwhile endeavor. Consider that most of the birds coming south during the migration will be adorned in this fashion. The birds of North America are in their greatest numerical mass of the year right now, and nearly all are females, juveniles, other non-adults, or molting males. There are few males in breeding plumage among the autumn waves of migrants. In the coming months, there will be an abundance of opportunities to enjoy these marvels on wings, so getting to know the birds in non-breeding feathers is time well spent. Make haste and get ready. For our feathered friends, it’s autumn and they’re on their way south.
Dunne, Pete. 2006. Pete Dunne’s Essential Field Guide Companion. Houghton Mifflin Company. New York.
Hayman, Peter; John Marchant, and Tony Prater. 1986. Shorebirds, An Identification Guide to the Waders of the World. Houghton Mifflin Company. New York.
Kauman, Kenn. 1996. Lives of North American Birds. Houghton Mifflin Company. New York.
McCullough, Mark A. 1989. Molting Sequence and Aging Of Bald Eagles. The Wilson Bulletin. 101:1-10.