Rodents (Rodentia) – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

January 26, 2024January 26, 2024

The Fog of a January Thaw

As week-old snow and ice slowly disappears from the Lower Susquehanna River Watershed landscape, we ventured out to see what might be lurking in the dense clouds of fog that for more than two days now have accompanied a mid-winter warm spell.

York Haven Dam Powerhouse — After freezing to a slushy consistency earlier this week, the Susquehanna is already beginning to thaw. Below the York Haven Dam at Conewago Falls, the water is open and ice-free.

Mallards and a pair of American Wigeon on a frozen lake. — On frozen man-made lakes and ponds, geese and ducks like these Mallards and American Wigeon are presently concentrated around small pockets of open water.

American Robin in a Callery pear — During the past ten days, American Robin numbers have exploded throughout the lower Susquehanna valley. The majority of these birds may be a mix of both those coming south to escape the late onset of wintry conditions to our north and those inching north into our region as early spring migrants.

American Robin — The January thaw has melted the snow from lawns and fields to provide thousands of visiting robins with a chance to forage for earthworms.

Cooper's Hawk — A visit by this young Cooper’s Hawk to the susquehannnawildlife.net headquarters garden sent songbirds scrambling…

…but did nothing to unnerve our resident Eastern Gray Squirrels,…

But earlier in the week, when heavy snow cover in the rural areas surrounding our urbanized neighborhood made it difficult for rodent-eating raptors to find food, we received brief visits from both a Red-tailed Hawk…

…and this young Red-shouldered Hawk, an uncommon bird of prey most often found in wet woods and other lowlands.

Red-shouldered Hawk in flight. — Unimpressed, each of our visiting buteos remained for just a few minutes before moving on in search of more favorable hunting grounds and prey.

Early Successional Growth — As snow melted and exposed bare ground in fields of early successional growth, we encountered…

…a flock of White-crowned Sparrows, most in first-winter plumage…

…and at least a dozen American Tree Sparrows. During the twentieth century, these handsome songbirds were regular winter visitors to the lower Susquehanna region. During recent decades, they’ve become increasingly more difficult to find. Currently, moderate numbers appear to be arriving to escape harsher weather to our north.

Adult Male Northern Harrier — What could be more appropriate on a foggy, gray evening than finding a “gray ghost” (adult male Northern Harrier) patrolling the fields in search of mice and voles.

If scenes of a January thaw begin to awaken your hopes and aspirations for all things spring, then you’ll appreciate this pair of closing photographs…

Pileated Woodpecker in Silver Maple — The maroon-red flower buds of Silver Maples are beginning to swell. And woodpeckers including Pileated Woodpeckers are beginning to drum, a timber-pounding behavior they use to establish breeding territories in habitats with suitable sites for cavity nesting.

In wet soil surrounding spring seeps and streams, Skunk Cabbage is rising through the leaf litter to herald the coming of a new season. Spring must surely be just around the corner.

November 23, 2023

Time to Eat

A glimpse of the rowdy guests crowding the Thanksgiving Day dinner table at susquehannawildlife.net headquarters…

A male White-breasted Nuthatch visits a peanut feeder…

A male Downy Woodpecker gets a bill full of suet.

A territorial Northern Mockingbird stands guard over its supply of Common Winterberry fruit.

To avoid the mockingbird’s aggression, the Eastern Bluebirds opted out of fresh fruit in favor of raisins offered at the feeders.

After everyone has had their fill, Dark-eyed Juncos clean up the leftovers.

September 11, 2023September 12, 2023

A Visit to a Beaver Pond

To pass the afternoon, we sat quietly along the edge of a pond created recently by North American Beavers (Castor canadensis). They first constructed their dam on this small stream about five years ago. Since then, a flourishing wetland has become established. Have a look.

A beaver lodge. — The beaver lodge was built among shrubs growing in shallow water in the middle of the pond.

Woolgrass in a beaver pond. — Woolgrass (Scirpus cyperinus) is a bulrush that thrives as an emergent and as a terrestrial plant in moist soils bordering the pond.

A male Common Whitetail dragonfly keeping watch over his territory.

A Twelve-spotted Skimmer perched on Soft Rush.

A Blue Dasher dragonfly seizing a Fall Field Cricket (Gryllus pennsylvanicus).

A Spicebush Swallowtail visiting Cardinal Flower. — A Spicebush Swallowtail visiting a Cardinal Flower.

A Green Heron looking for small fish, crayfish, frogs, and tadpoles.

A Green Heron stalks potential prey. — The Green Heron stalking potential prey.

A Wood Duck feeding on Lesser Duckweed. — A Wood Duck feeding on the tiny floating plant known as Lesser Duckweed (Lemna minor).

A Least Sandpiper feeding along the muddy edge of a beaver pond. — A Least Sandpiper poking at small invertebrates along the muddy edge of the beaver pond.

A Solitary Sandpiper testing the waters for proper feeding depth.

A Pectoral Sandpiper searches for its next morsel of sustenance.

A Sora rail in a beaver pond. — The Sora (Porzana carolina) is a seldom seen rail of marshlands including those created by North American Beavers. Common Cattails, sedges, and rushes provide these chicken-shaped wetland birds with nesting and loafing cover.

Isn’t that amazing? North American Beavers build and maintain what human engineers struggle to master—dams and ponds that reduce pollution, allow fish passage, and support self-sustaining ecosystems. Want to clean up the streams and floodplains of your local watershed? Let the beavers do the job!

June 23, 2023June 23, 2023

Peanuts! Get Your Peanuts!

Red-bellied Woodpecker on Peanut Feeder — Don’t want to feed suet to the birds around your home during the blazing heat of summer? Well, you might be glad to know that peanuts offered in one of these expanded metal tube feeders make a great substitute. They provide a nutritious supplement to naturally occurring foods for nuthatches, chickadees, Tufted Titmice, Carolina Wrens, Blue Jays, finches, and woodpeckers including this Red-bellied Woodpecker. Secured to a vertical length of wire hung from a horizontal tree limb, these feeders have proven so puzzling to the squirrels at susquehannawildlife.net headquarters that they no longer make any effort to raid them.

Though marketed primarily to dispense suet nuggets, powder-coated metal mesh feeders can be used for sunflower seeds too. This juvenile House Finch plucks the black oil variety from one of the tubes in our garden. Seeds that fall are quickly scarfed up by ground-feeding species including Northern Cardinals, Eastern Chipmunks (Tamias striatus), and frustrated squirrels. Fewer seeds are lost if the larger varieties of sunflower such as “grey stripe” are used.

April 16, 2023April 17, 2023

Photo of the Day

Three young Eastern Gray Squirrels investigate the world outside the nest cavity that has been their home since birth.

February 2, 2023

Photo of the Day

November 26, 2022September 13, 2023

The Gasoline and Gunpowder Gang’s Second-biggest Holiday of the Year

For members of the gasoline and gunpowder gang in Pennsylvania, the coming two weeks are the second-biggest holiday of the year. Cloaked in ceremonial orange, worshipers of the White-tailed Deity are making their annual pilgrimage into the great outdoors to beat the bushes in search of their idol. For the fortunate among the faithful, their devotion culminates in a testosterone/adrenaline-charged sacrifice of the supreme being.

Remember, emotions run high during this blood-letting festival—sometimes overwhelming secular attributes like logic and rational decision-making. You don’t want to be in the crossfire—so stay out of the woods!

September 27, 2022

Photo of the Day

Mammals of the Lower Susquehanna River Watershed: A White-footed Mouse Peers from its Nest — Uncle Tyler Dyer reminds all his vegetarian friends to speak clearly when ordering the “House Salad” in a noisy restaurant, otherwise you may go hungry. Unlike Uncle Ty, the White-footed Mouse (Peromyscus leucopus), seen here in its nest, is omnivorous, so it seldom goes hungry.

April 14, 2022September 12, 2023

Emergence of the Turtles

Along the lower Susquehanna, an unseasonably mild day in early spring can provide an observer with the opportunity to witness an annual spectacle seldom seen by the average visitor to the river—concentrations of dozens, sometimes hundreds, of turtles as they emerge from their winter slumber to bathe in the year’s first surge of warm air and sunshine.

Reptiles of the Lower Susquehanna River Watershed: Snapping Turtle — Snapping Turtles (Chelydra serpentina) spend the winter buried in mud along the river shoreline and in nearby Alluvial Terrace Wetlands. We photographed this one just as it was digging its way out.

Reptiles of the Lower Susquehanna River Watershed: Painted Turtles — Freshly emerged Painted Turtles clamber onto a log to bask in the cloud-filtered sun.

Reptiles of the Lower Susquehanna River Watershed: Painted Turtle atop a Snapping Turtle — A Painted Turtle looking for a place to get out of the chilly water soon discovered the obvious solution.

It’s catching on, more Painted Turtles atop a Snapping Turtle in an Alluvial Terrace Wetland.

Reptiles of the Lower Susquehanna River Watershed: Red-eared Slider and Common Map Turtle — The Common Map Turtle (right) is the turtle most frequently observed basking on rocks and logs along the main stem of the Susquehanna. To the left is a Red-eared Slider (Trachemys scripta elegans), an increasingly numerous invasive species. The first Red-eared Sliders arrived in the river as, you guessed it, unwanted pets. Editor’s Note: Special thanks to the local North American Beaver (Castor canadensis) for trimming the trees and providing a clear shot for this photograph!

Reptiles of the Lower Susquehanna River Watershed: Red-eared Slider and Painted Turtles — And now, a quick quiz. Name the things that don’t belong in this picture? Here’s a hint: a non-native Red-eared Slider (left) joins indigenous Painted Turtles atop a discarded tire in an Alluvial Terrace Wetland in Dauphin County, Pennsylvania.

February 19, 2022

Photo of the Day

Mammals of the Lower Susquehanna River Watershed: Eastern Gray Squirrel — An Eastern Gray Squirrel turns its back on today’s gusty snow squall.

January 29, 2022August 15, 2022

Five Best Values for Feeding Birds

Despite being located in an urbanized downtown setting, blustery weather in recent days has inspired a wonderful variety of small birds to visit the garden here at the susquehannawildlife.net headquarters to feed and refresh. For those among you who may enjoy an opportunity to see an interesting variety of native birds living around your place, we’ve assembled a list of our five favorite foods for wild birds.

American Goldfinches in drab winter (basic) plumage visit the trickle of water entering the headquarters pond to bathe and drink. In addition to offering the foods animals need to survive, a source of clean water is an excellent way to attract wildlife to your property.

The selections on our list are foods that provide supplemental nutrition and/or energy for indigenous species, mostly songbirds, without sustaining your neighborhood’s non-native European Starlings and House Sparrows, mooching Eastern Gray Squirrels, or flock of ecologically destructive hand-fed waterfowl. We’ve included foods that aren’t necessarily the cheapest but are instead those that are the best value when offered properly.

Bread, “bargain” seed mixes, and cracked corn can attract and sustain large numbers of House Sparrows and European Starlings. Both are non-native species that compete mercilessly with indigenous birds including bluebirds for food and nesting sites. Though found favorable for feeding Northern Cardinals without attracting squirrels, the expensive safflower seed seen here is another favorite of these aggressive House Sparrows. Ever wasteful, they “shovel” seed out of feeders while searching for the prime morsels from which they can easily remove the hulls. Trying not to feed them is an ongoing challenge, so we don’t offer these aforementioned foods to our avian guests.

Number 5

Raw Beef Suet

In addition to rendered beef suet, manufactured suet cakes usually contain seeds, cracked corn, peanuts, and other ingredients that attract European Starlings, House Sparrows, and squirrels to the feeder, often excluding woodpeckers and other native species from the fare. Instead, we provide raw beef suet.

Because it is unrendered and can turn rancid, raw beef suet is strictly a food to be offered in cold weather. It is a favorite of woodpeckers, nuthatches, and many other species. Ask for it at your local meat counter, where it is generally inexpensive.

Raw beef suet is fat removed from areas surrounding the kidneys on a beef steer. To avoid spoiling, offer it only in the winter months, particularly if birds are slow to consume the amount placed for them. If temperatures are above freezing, it’s important to replace uneaten food frequently. The piece seen here on the left was stored in the freezer for almost a year while the rancid piece to the right was stored in a refrigerator at about 40 degrees Fahrenheit for just two months. You can render raw beef suet and make your own cakes by melting it down and pouring it into a form such as cupcake tin. But do it outdoors or you’ll be living alone for a while.

A female Downy Woodpecker feeds on raw beef suet stuffed into holes drilled into a vertically hanging log. Because they can’t be cleaned, log feeders should be discarded after one season. Wire cage feeders though, can usually be scrubbed, disinfected, dried, and reused.

Pesky European Starlings might visit a raw beef suet feeder but won’t usually linger unless other foods to their liking are available nearby.

This male Downy Woodpecker has no trouble feeding on raw beef suet packed into holes drilled into the underside of this horizontally hanging log. Starlings don’t particularly care to feed this way.

Unusual visitors like a Brown Creeper are more likely to stop by at a suet feeder when it isn’t crowded by raucous starlings, House Sparrows, and squirrels. This one surprised us just this morning.

Below the feeders, scraps of suet that fall to the ground are readily picked up, usually by ground-feeding birds. In this instance, a male Eastern Bluebird saw a chunk break loose and pounced on it with haste.

Number 4

Niger (“Thistle”) Seed

Niger seed, also known as nyjer or nyger, is derived from the sunflower-like plant Guizotia abyssinica, a native of Ethiopia. By the pound, niger seed is usually the most expensive of the bird seeds regularly sold in retail outlets. Nevertheless, it is a good value when offered in a tube or wire mesh feeder that prevents House Sparrows and other species from quickly “shoveling” it to the ground. European starlings and squirrels don’t bother with niger seed at all.

Niger seed must be kept dry. Mold will quickly make niger seed inedible if it gets wet, so avoid using “thistle socks” as feeders. A dome or other protective covering above a tube or wire mesh feeder reduces the frequency with which feeders must be cleaned and moist seed discarded. Remember, keep it fresh and keep it dry!

Niger (“thistle”) seed is very small, so it is offered in specialized feeders to prevent seed from spilling out of oversize holes as waste.

An American Goldfinch in winter plumage feeding on niger seed from a wire mesh feeder. By April, goldfinches are molting into spectacular breeding feathers. Niger seed can be offered year-round to keep them visiting your garden while they are at maximum magnificence.

American Goldfinches in August. This tube feeder is designed specifically for goldfinches, birds that have no difficulty hanging upside down to grab niger seed from small feeding ports.

During invasion years, visiting Pine Siskins favor niger seed at feeding stations.

Like goldfinches, Pine Siskins are quite comfortable feeding upside down on specialized tubes with perches positioned above the seed ports. Seeds dropped to the ground are readily picked up by ground-feeding birds including Mourning Doves and Dark-eyed Juncos. Periodically, uneaten niger seed should be swept up and discarded.

Number 3

Striped Sunflower Seed

Striped sunflower seed, also known as grey-striped sunflower seed, is harvested from a cultivar of the Common Sunflower (Helianthus annuus), the same tall garden plant with a massive bloom that you grew as a kid. The Common Sunflower is indigenous to areas west of the Mississippi River and its seeds are readily eaten by many native species of birds including jays, finches, and grosbeaks. The husks are harder to crack than those of black oil sunflower seed, so House Sparrows consume less, particularly when it is offered in a feeder that prevents “shoveling”. For obvious reasons, a squirrel-proof or squirrel-resistant feeder should be used for striped sunflower seed.

A male House Finch and a Carolina Chickadee pluck striped sunflower seeds from a squirrel-resistant powder-coated metal-mesh tube feeder.

An American Goldfinch in winter plumage finds striped sunflower seeds irresistible, even with niger seed being offered in an adjacent feeder.

A Tufted Titmouse visits a feeder stocked with striped sunflower seeds.

Northern Cardinals readily feed on striped sunflower seeds, especially those that fall from our metal-mesh tube feeders.

An Eastern Gray Squirrel (*Sciurus carolinensis*) has no choice but to be satisfied with striped sunflower seeds that spill from our wire-mesh tube feeders.

Number 2

Mealworms

Mealworms are the commercially produced larvae of the beetle Tenebrio molitor. Dried or live mealworms are a marvelous supplement to the diets of numerous birds that might not otherwise visit your garden. Woodpeckers, titmice, wrens, mockingbirds, warblers, and bluebirds are among the species savoring protein-rich mealworms. The trick is to offer them without European Starlings noticing or having access to them because European Starlings you see, go crazy over a meal of mealworms.

A male Eastern Bluebird tossing and grabbing a dried mealworm.

A female Eastern Bluebird with a dried mealworm.

A pair of Eastern Bluebirds. The value of mealworms is self-evident: you get to have bluebirds around.

To foil European Starlings, we assembled this homemade mealworm feeder from miscellaneous parts. The bluebirds took right to it.

It frustrates the starlings enough to discourage them from sticking around for long.

If you’re offering dried mealworms, a source of clean water must be available nearby so that the bluebirds and other guests at your feeder don’t become dehydrated.

Number 1

Food-producing Native Shrubs and Trees

The best value for feeding birds and other wildlife in your garden is to plant food-producing native plants, particularly shrubs and trees. After an initial investment, they can provide food, cover, and roosting sites year after year. In addition, you’ll have a more complete food chain on a property populated by native plants and all the associated life forms they support (insects, spiders, etc.).

In your garden, a Northern Mockingbird may defend a food supply like these Common Winterberry fruits as its sole means of sustenance for an entire winter season. Having an abundance of plantings assures that in your cache there’s plenty to eat for this and other species.

The American Goldfinches currently spending the winter at our headquarters are visiting the feeders for niger and striped sunflower seeds, but the bulk of their diet consists of tiny seeds from the cones on our Eastern Hemlock trees. At night, birds obtain shelter from the weather by roosting in this clump of evergreens.

While the Eastern Bluebirds visiting the susquehannawildlife.net headquarters are fond of mealworms, the bulk of their diet here consists of these Common Winterberry fruits and the berries on our American Holly trees.

Cedar Waxwings are readily attracted to red berries including Common Winterberry fruit.

Migrating American Robins visit the headquarters garden in late winter each year to devour berries before continuing their journey to the north.

Your local County Conservation District is having its annual spring tree sale soon. They have a wide selection to choose from each year and the plants are inexpensive. They offer everything from evergreens and oaks to grasses and flowers. You can afford to scrap the lawn and revegetate your whole property at these prices—no kidding, we did it. You need to preorder for pickup in the spring. To order, check their websites now or give them a call. These food-producing native shrubs and trees are by far the best bird feeding value that you’re likely to find, so don’t let this year’s sales pass you by!

October 12, 2021October 12, 2021

Photo of the Day

The Woodchuck (Marmota monax), also known as the groundhog, gets no respect. Shouldn’t it be the official state mammal of Pennsylvania? After all, a nationally recognized holiday centers on the prognostications of the state’s favorite son, “Punxsutawney Phil”. And think of all those state lottery tickets sold by that media groundhog, “Gus”. Yep, only Pennsylvania would have an animal often named for a different state as its official mammal: the Virginia White-tailed Deity.

July 31, 2017November 29, 2019

Digging In

If you visit the shores of the Susquehanna River during the warmer months of the year, there’s a pretty good probability that you’ll be taking a visitor along home with you. Not to worry, it won’t raid the icebox or change the television channels when you leave the room to get a snack. It won’t put you in the doghouse with the landlord for having a forbidden pet. As a matter of fact, you may not even notice your new companion. Sure enough though, it’s there, crawling through the luxurious warm fabric of your clothing and seeking out a good place to dig in and chow down. O.K., so now you’re worried.

Ticks, particularly the American Dog Tick (Dermacentor variabilis), are widespread in the Lower Susquehanna River Watershed. Like spiders, they are arachnids. They have a four-stage life cycle (egg-larva-nymph-adult) which, in the case of D. variabilis, requires a minimum of two months to complete. Females lay up to 6,500 eggs on the ground. Then the fun begins as the larvae with any hope of survival must attach to a small mammal to feed. They can survive for almost a year before finding a host. After a successful hookup and subsequent blood feast of up to two weeks duration, the larva drops to the ground, molts into a nymph, and finds another small mammal, usually a bit bigger this time, to feed upon. A nymph can survive for up to six months before needing to feed. Finding the second host, the nymph feeds for 3 to 10 days, then drops to the ground to molt into an adult. Adult American Dog Ticks can endure up to two years without feeding on a host. The adults mate and feed on larger mammals such as deer and domestic animals including, of course, dogs. After a blood meal of five days to two weeks duration, the adult female tick drops to the ground to lay eggs and initiate a new generation.

The adult American Dog Tick attaches to a potential host by hanging from vegetation and grabbing the passing victim with its forward legs to hitch a ride. If undetected, a female will find a nice warm spot and “dig in” to begin feeding. This male is looking for love, and in all the wrong places.

The American Dog Tick is renowned as a carrier of the Rocky Mountain Spotted Fever bacteria (Rickettsia rickettsii). The bacteria is vectored by the ticks from rodents to dogs and humans. The adult tick must be attached to the victim for a minimum of six to eight hours to transmit the pathogen. A rash spreading from the wrists and the ankles to other portions of the body begins two to fourteen days after infection.

Tularemia, caused by the bacteria Francisella tularensis, can be passed by the American Dog Tick. Symptoms can appear in three to twenty-one days and include chills, fever, and inflammation of the lymph nodes.

American Dog Ticks which attach to dogs, particularly near the neck, and are left in place to feed and engorge themselves for longer than five days can cause Canine Tick Paralysis. Symptoms usually begin to subside only after a recovery period following removal of the arachnid.

The American Dog Tick is exposed to Borrelia burgdorferi, the bacteria responsible for Lyme Disease, however, transmittal of this pathogen is by the smaller Deer Tick (Ixodes scapularis), also known as the Black-legged Tick. The Deer Tick is not presently common at Conewago Falls. In the adjacent uplands, it is widespread and is carrying Lyme Disease where the White-tailed Deity (Odocoileus virginianus), the preferred host for the ticks, is found along with mice and other small rodents, the source of B. burgdorferi bacteria. The Deer Tick easily escapes notice and cases of Lyme Disease are frequent, so vigilance is necessary.

SOURCES

Chan, Wai-Han, and Kaufman, Phillip. 2008. American Dog Tick. University of Florida Featured Creatures website entnemdept.ufl.edu/creatures/urban/medical/american_dog_tick.htm as accessed July 30, 2017.