While crayfish are the most common crustacean in the United States, we don’t often see them on on the farm. This one was found by my son in the barely seeping headwaters of Carroll Creek. There is one fact that everyone should know about crayfish: they eat almost everything. Omnivores in the extreme, there’s nothing a crayfish won’t try: insects, tadpoles, algae, plants, dead animals, etc. They’ll feast on almost anything. In fact, one source states that 40% of their brain is devoted to their sense of smell – your brain only uses 1% – in order to help them find food.
Eastern tent caterpillars are generally not well liked. They can quickly defoliate small trees and gather in repulsive, squirming colonies. As if that weren’t bad enough, pregnant mares who accidently eat tent caterpillars are known to abort their fetuses. These facts make it even more surprising that these creatures are in fact one of the most fascinating caterpillars found on the farm. Not only are the amazingly sociable larvae capable of building the biggest nest of any tent caterpillar, they also vomit deadly cyanide when threatened.
Their nests are engineering marvels that are carefully constructed to keep the caterpillars warm. This is important because they can’t digest their food if they get too cold. Nests are typically started where two branches divide and expanded daily with new layers of silk. The widest side of a nest often faces the morning sun to capture as much warmth as possible. After several weeks, the nests develop into a multi-chambered, greenhouse-like structures that allow the caterpillars to control their body temperature. Their habit of gathering together in a large mass is also believed to have evolved in an effort to keep warm.
Their ability to produce cyanide is partially a result of their prefered diet of cherry tree leaves. Cherry leaves – especially those from the black cherry tree – are cyanogenic and provide the caterpillar with the raw materials necessary to make the poison. As a result, tent caterpillars are threatened by few predators other than the parasitic wasps and flies who lay their eggs on unsuspecting larvae.
While undeniably destructive, the damage done by these caterpillars often does not have a significant economic impact. Infested trees are typically ornamental and quickly sprout new leaves once the larvae leave to start the next phase of their life cycle.
The Variegated Fritillary is one of the many butterflies that enliven the farm’s fields and roadsides from late spring through fall. While it thrives from Argentina northward to North America’s East Coast, its amazingly wide range also includes much of the United States and even extends into Canada. The fritillary’s caterpillar hosts on leafy plants and vines including mayapple, moonseed, violets, and pansies. Adults typically feed on nectar from butterfly weed, milkweed, red clover, and, as seen in the photo, tickseed sunflower (Bidens aristosa).
A grove of ancient pecan trees draws a large number of gray squirrels to the farm. These industrious mammals are scatter hoarders. They hide thousands of caches every year and feed on the stored nuts and seeds during times of scarcity. Gray squirrels primarily nest in collections of sticks and leaves called dreys or hollow tree trunks. They also do not hibernate. Instead they often share their nests with other squirrels on cold winter nights. Crepuscular by nature, gray squirrels are most active in the early morning and evenings.
Up until about a year ago I never expected to see a bald eagle on the farm. Due to excessive hunting by humans and the insecticide DDT, bald eagles were considered endangered or threatened for much of my childhood. Combined with the fact that they are sea eagles and principally eat fish, it was absurd to think I would ever see one in this part of Virginia. Yet here they are. Incredibly, it might even be a breeding pair that’s been visiting the farm over the past several days.
Their resurgence is the result of an amazing conservation effort. In the 1950s there were only 412 known nesting pairs. With the banning of DDT and severe restrictions on hunting, the birds are no longer listed as endangered or even threatened. Their increased numbers means that they are starting to re-occupy territory in parts of the United States where they have not been seen in living memory. Extremely cagey and hyper-alert, I have yet to get close enough for a decent photo of these amazing birds of prey. Even so, it is always inspiring to see this massive eagle – their average wing span can be 7-1/2 feet wide – take flight and soar over the family farm.
Found commonly over much of the east coast and as far west as Texas, the pickerel frog lives happily in Virginia’s Piedmont. While it looks similar to the leopard frog, the pickerel’s distinctive rectangular spots are an easy way to tell the two species apart. As you would expect of any frog, the pickerel is often found near streams and ponds. The lack of webbing between its toes also suggests that it spends more time on land than other frogs.
Amazingly, the pickerel frog is the only poisonous frog native to North America. Similar to eastern American toads, the toxin it secretes through its skin is only mildly irritating to humans if rubbed in the eyes or mucus membranes. However, its poison is more potent to smaller animals and even deadly to amphibians.
Doves. Pigeons. Flying rats. Birds from the Columba family are called by many names. Rock Doves are one of the most common birds in the world. While they are now found in almost every major city worldwide, their native habitat is Europe, North Africa, and South Asia. On the farm they typically roost under the hay hood of the barn and scavenge seeds in the surrounding fields.
Rock doves are known for being monogamous with both parents caring for clutches of one to two eggs. Amazingly, both parents also produce “crop milk” to nourish the squabs through their first week of life. Unique to doves, flamingos, and some penguins, crop milk is a dense mixture of fat and protein produced by the crop lining. The cheese-like secretion also contains antioxidants, bacteria, and immune-enhancing compounds.
Young squab is a also delicacy. While now they can be found in grocery stores, in 18th and early-19th Virginia wealthy landowners occasionally built elaborate dovecotes to attract breeding doves. These buildings – with their warm and cozy nesting boxes – allowed the gentry to easily harvest the young birds just days before they took their first flight.
One of the most common dragonflies in the United States, widow skimmers can be seen throughout North America. While they are often found near still bodies of water, this skimmer was instead photographed in the vegetable garden hunting asparagus beetle larvae. I hope it did not flyaway hungry.
The widow skimmer in the photo is a juvenile. As it grows to adulthood, its body will turn powdery blue. Widow skimmers are also easy to identify as they are the only species of skimmers with broad stripes on both the fore- and hindwings. Adult male skimmers can also be quickly identified by bands of white on their wings.
A bain of tomato growers, tobacco hornworms can defolate young tomato plants with alarming speed. They can grow to over three-inches long and feed primarily on tomato or tobacco plants. If a hornworm is lucky enough to survive pupatation, its adult form is a large moth with yellow-orange spots on its abdomen and a four-inch wing span.
These impressively large and fleshy caterpillars are very similar to tomato hornworms. The color of the “horn” on their tail is perhaps the easiest way to tell the difference. A tomato hornworm will have a blue horn while the tobacco hornworm’s tail is red. Another easily identifiable difference are the extra black edges lining the stripes found on a tobacco hornworm’s back.
These worms must have been endemic when tobacco ruled the Piedmont’s agricultural landscape in the 18th and early-19th centuries. However, today they are not a major nuisance to the farm’s very limited number of tomato plants. Tilling in the spring usually breaks up their pupae and, if that doesn’t work, they can be easily plucked. More interesting are the parasitic wasps that use hornworms to complete their lifecycle. Unlike some parasitic wasps who paralyze their victims before dragging them back to an underground burrow, wasps who host on hornworms lay their eggs directly on their prey. After the eggs hatch the wasp larvae feed relentlessly on the slowly dying caterpillar until they are ready to take their adult form. Brutal but effective.
Often seen sitting on fences and branches near fields and lawns, the Eastern Bluebird is a farm favorite. Brightly colored males and elegant greyish females are quick to take advantage of nesting boxes mounted to abandoned fence posts and trees. It is the male who first finds a nesting site. While he works to attract a discerning female to the nest with his striking orange chest plumage and symbolic offerings of twigs and leaves, he must also aggressively protect it from other birds. If he manages to charm a mate with his display, the female will then complete the nest and lay two to seven pale blue eggs. The eggs – 20% of which may have been fertilized by alternative male partners – will hatch 11-19 days later. Their bond often lasts several seasons and commonly produces more than one brood a year. Hatchlings from spring broods leave their parents in mid-summer; broods raised later in the year may travel with their parents throughout the winter.
Typically feeding on insects during the spring and summer, the Eastern Bluebird is a savvy hunter who pounces on unsuspecting prey from above. Their remarkably keen eyesight – they are capable of seeing their quarry from 60 feet away – helps them to track down the beetles, caterpillars, spiders, and grasshoppers they prefer. Bluebirds relay on berries and other fruits during the colder months when insects are not as prevalent.
With an estimated global population of 22 million, bluebirds are thankfully very common. However, even with their large numbers and low conservation threat, their cheerful demeanor and insectivorous diet makes installing nesting boxes well worth the effort.