Wagtails and Pipits (Motacillidae) – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

January 22, 2024January 22, 2024

Birds Along the River’s Edge

Just as bare ground along a plowed road attracts birds in an otherwise snow-covered landscape, a receding river or large stream can provide the same benefit to hungry avians looking for food following a winter storm.

Here is a small sample of some of the species seen during a brief stop along the Susquehanna earlier this week.

Along vegetated edges of the Susquehanna and its tributaries, the Song Sparrow is ubiquitous in its search for small seeds and other foods. As the river recedes from the effects of this month’s rains, the shoreline is left bare of more recently deposited snow cover. Song Sparrows and other birds are attracted to streamside corridors of frost-free ground to find sufficient consumables for supplying enough energy to survive the long cold nights of winter.

Thousands of American Robins have been widespread throughout the lower Susquehanna valley during the past week. Due to the mild weather during this late fall and early winter, some may still be in the process of working their way south. Currently, many robins are concentrated along the river shoreline where receding water has exposed unfrozen soils to provide these birds with opportunities for finding earthworms (Lumbricidae) and other annelids.

This Golden-crowned Kinglet was observed searching the trees and shrubs along the Susquehanna shoreline for tiny insects and spiders. Temperatures above the bare ground along the receding river can be a few degrees higher than in surrounding snow-covered areas, thus improving the chances of finding active prey among the trunks and limbs of the riparian forest.

Not far from the kinglet, a Brown Creeper is seen searching the bark of a Silver Maple (Acer saccharinum) for wintering insects, as well as their eggs and larvae. Spiders in all their life stages are a favorite too.

American Pipits not only inhabit farm fields during the winter months, they are quite fond of bare ground along the Susquehanna. Seen quite easily along a strip of pebbly shoreline exposed by receding water, these birds will often escape notice when spending time on mid-river gravel and sand bars during periods of low flow.

An American Pipit on a bitterly cold afternoon along the Susquehanna.

January 6, 2024January 6, 2024

Birds of Snow-covered Farmland

When the ground becomes snow covered, it’s hard to imagine anything lives in the vast wide-open expanses of cropland found in the Lower Susquehanna River Watershed’s fertile valleys.

Snow-covered Farm Field — A snow-covered field with no standing vegetation. For nearly all wild birds, mammals, and other animals, modern agricultural practices offer no means of sustenance, particularly during the winter months.

Yet, there is one group of birds that can be found scrounging a living from what little exists after a season of high-intensity farming. Meet the Horned Lark.

Horned Larks occur year-round in the lower Susquehanna region. Birds found wintering here are hardy individuals that breed in the arctic tundra, terrain reminiscent of our treeless farmlands. Another population of larks seems to have adapted to no-till farming, nesting with some success in unplowed fields during the early part of the growing season. The impact of herbicide application on survival of these broods could be a topic of research for an energetic student out there…hint, hint.

A Flock of Horned Larks — Nearly invisible on bare ground, Horned Larks are much more conspicuous after a fresh snowfall. For protection from predators, they gather in flocks. During the days of raw manure application, 300 to 500 larks could be found attracted to a freshly spread strip in a snow-covered field. Modern liquid manure, which contains fewer undigested seeds and grains for larks, is not as attractive to these and other birds.

Horned Larks in Snow — During severe storms, we’ve seen Horned Larks remain active throughout the night. We’ve even witnessed them taking shelter by burying themselves in the snow.

Horned Lark in Flight — To find food, Horned Larks are constantly on the move…

Horned Lark — …seeking out bare ground or the seed-bearing tops of plant stems that remain exposed above the snow.

Horned Larks Feeding at Roadside — Following storms, Horned Larks often gather along roadsides where snow removal has revealed “weed” seeds and other tiny morsels that, though they are almost imperceptible to us, are a meal for a Horned Lark.

A Horned Lark munching "weed" seeds. — A Horned Lark munching “weed” seeds.

Horned Larks and Lapland Longsrurs — Flocks of wintering Horned Larks will sometimes contain one or more of the several much less numerous species with a similar proclivity for tundra-like environs during the colder months. We examined this gathering a little bit more closely…

Lapland Longspurs and Horned Larks — …and found these Lapland Longspurs (Calcarius lapponicus). In winter, Lapland Longspurs (the two streaked birds: one to the far left and the other high-stepping the white line) can be hard to discern from the earth tones of farmland habitat. Breeding males, however, are a brilliant white with a chestnut-colored nape and a black bib, mask, and cap. On rare occasions, these males in spectacular alternate plumage can be found in the lower Susquehanna valley prior to their departure to nesting areas near the treeline in northern Canada and Alaska.

A close-up image (through the windshield) of a roadside flock of Horned larks and three Lapland Longspurs (top, far right, and third from bottom).

If you decide to take a little post-storm trip to look for Horned Larks and Lapland Longspurs, be sure to drive carefully. Do your searching on quiet rural roads with minimal traffic. Stop and park only where line-of-sight and other conditions allow it to be done safely. Use your flashers and check your mirrors often. Think before you stop and park—don’t get stuck or make a muddy mess. And most important of all, be aware that you’re on a roadway—get out of the way of traffic.

Flushed from roadside feeding areas by passing automobiles, these Eastern Meadowlarks were previously displaced from their grassland and pasture foraging areas by snow cover.

If you’re not going out to look for larks and longspurs, we do have a favor to ask of you. Please remember to slow down while you’re driving. Not only is this an accident-prone time of year for people in cars and trucks, it’s a dangerous time for birds and other wildlife too. They’re at greatest peril of getting run over while concentrated along roadsides looking for food following snow storms.

The American Pipit is another barren-field specialist that can be found feeding at roadside following snowstorms, particularly when they coincide with the bird’s migration in late fall or early spring. (Vintage 35 mm image)

The Snow Bunting (Plectrophenax nivalis), like the Lapland Longspur, occurs among flocks of Horned Larks in winter. Other barren-ground birds you’ll see feeding along country roads following significant snowfalls include Savannah and Vesper Sparrows.

During mild winters, Killdeer may linger in farmlands where they are more easily heard than seen…until it snows.

October 14, 2017September 4, 2019

State of Confusion

The humid rainy remains of Hurricane Nate have long since passed by Pennsylvania, yet mild wet weather lingers to confuse one’s sense of the seasons. This gloomy misty day was less than spectacular for watching migrating birds and insects, but some did pass by. Many resident animals of the falls are availing themselves of the opportunity to continue active behavior before the cold winds of autumn and winter force a change of lifestyle.

Warm drizzle at daybreak prompted several Northern Spring Peepers (Pseudacris crucifer crucifer) to begin calling from the wetlands in the Riparian Woodlands of Conewago Falls. An enormous chorus of these calls normally begins with the first warm rains of early spring to usher in this tiny frog’s mating season. Today, it was just a few “peeps” among anxious friends.

The tiny Northern Spring Peeper is recognized by the dark “X” across its back. Soon, shelter must be found among loose bark and fallen logs to commence hibernation. Emergence, often prompted by warm spring rains, will quickly be followed by a growing chorus of breeding calls as sometimes hundreds of these frogs assemble in vernal pools where mating will then occur.

Any additional river flow that resulted from the rains of the previous week is scarcely noticeable among the Pothole Rocks. The water level remains low, the water column is fairly clear, and the water temperatures are in the 60s Fahrenheit.

It’s no real surprise then to see aquatic turtles climbing onto the boulders in the falls to enjoy a little warmth, if not from the sun, then from the stored heat in the rocks. As usual, they’re quick to slide into the depths soon after sensing someone approaching or moving nearby. Seldom found anywhere but on the river, these skilled divers are Common Map Turtles (Graptemys geographica), also known as Northern Map Turtles. Their paddle-like feet are well adapted to swimming in strong current. They are benthic feeders, feasting upon a wide variety of invertebrates found among the stone and substrate of the river bottom.

Adult Common Map Turtles hibernate communally on the river bottom in a location protected from ice scour and turbulent flow, often using boulders, logs, or other structures as shelter from strong current. The oxygenation of waters tumbling through Conewago Falls may be critical to the survival of the turtles overwintering downstream. Dissolved oxygen in the water is absorbed by the nearly inactive turtles as they remain submerged at their hideout through the winter. Though Common Map Turtles, particularly males, may occasionally move about in their hibernation location, they are not seen coming to the surface to breathe.

The Common Map Turtles in the Susquehanna River basin are a population disconnected from that found in the main range of the species in the Great Lakes and upper Mississippi basin. Another isolated population exists in the Delaware River.

Common Map Turtles, including this recently hatched young seen in August, are often observed climbing onto rocks in the river.

Note the oversize swimming fin adaptations of the feet on this adult Common Map Turtle found among the Pothole Rocks in Conewago Falls. Young and adults are capable of navigating some strong current to feed and escape danger.

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SOURCES

Committee on the Status of Endangered Wildlife in Canada. 2002. Status Report of the Northern Map Turtle. Canadian Wildlife Service. Ottawa, Ontario.

September 30, 2017September 4, 2018

Swallows by the Thousands

A fresh breeze from the north brought cooler air and a reminder that summer is gone and autumn has arrived.

Fast-moving dark clouds provided a perfect backdrop for viewing passing diurnal migrants. Bald Eagles utilized the tail wind to cruise down the Susquehanna toward Chesapeake Bay and points further south. A migrating Merlin began a chase from which a Northern Flicker narrowly escaped by finding shelter among Pothole Rocks and a few small trees. The season’s first American Black Duck (Anas rubripes), Common Loon (Gavia immer), Yellow-bellied Sapsucker (Sphyrapicus varia), and American Pipits (Anthus rubescens) moved through.

Blue Jays continued their hesitant crossings of the river at Conewago Falls. The majority completed the journey by forming groups of a dozen or more birds and following the lead of a lone American Robin, a Northern Flicker, or, odd as it appeared, a small warbler.

By far the most numerous migrants today were swallows. Thousands of Northern Rough-winged Swallows and hundreds of Tree Swallows were on the wing in search of what was suddenly a sparse flying insect supply. To get out of the brisk wind, some of the more resourceful birds landed on the warm rocks. To satisfy their appetite, many were able to pick crawling arthropods from the surface of the boulders. They swallow them whole.