July 2020 – Discover-Nature

Woodpeckers

My backyard is filled with birds at this time of year, and some of the most distinctive ones flash through the trees and across the feeders with black and white wing bars and some bright red highlights. These are woodpeckers, in the family Picidae (pis-a-dee). Seven members of this family are found in DuPage County: downy woodpecker, Dryobates pubescens; hairy woodpecker, Dryobates villosus; red-headed woodpecker, Melanerpes erythrocephalus; pileated woodpecker, Dryocopus pileatus; Northern flicker, Colaptes auratus; red-bellied woodpecker, Melanerpes carolinus; and yellow-bellied sapsucker, Sphyrapicus varius.

Dryobates pubescens, Downy Woodpecker by Phil Myers

Dryobates villosus, Hairy Woodpecker by Phil Myers

Woodpeckers naturally live in areas with large tracts of woods. However, several of these species have adapted to living among human dwellings and backyard bird feeders. Primarily insect eaters, these birds can find food by foraging under tree bark and listening for insect movement, then chiseling away the bark to get to the prey. Sapsuckers drill out rows of holes across the bark and feed on the sap of the tree, as well as any insects drawn to the sap. Flickers, and pileated woodpeckers in particular, are known for the large quantities of ants they consume. Nuts, fruits and seeds supplement their diets. Some woodpeckers, including red-headed, downy and hairy may store food. The most commonly stored items are acorns, and storage sites are aggressively defended.

Melanerpes carolinus, Red-bellied woodpecker by Phil Myers

All woodpeckers are cavity nesters. Nests are thermal regulated to some extent by facing the opening to the nest to the south or east in cooler climates, and the north or west in warmer areas. Nests tend to be found in soft wood trees that are wide enough to support a cavity for both adults and young without coming near the sap layer just under the bark, so nests remain tidy. Cavities are never made above a branch, presumably so that rain water cannot run into the opening. Woodpeckers do not reuse old cavities, but these cavities are used by many other species in following years including squirrels, snakes and other bird species.

Sphyracipus varius, Yellow-bellied sapsucker by Phil Myers

Woodpeckers form long-term pair bonds except for sapsuckers who bond for one season. There is one brood a year and both males and females care for the young. Eggs are laid on a bed of new wood chips, and incubation lasts 11-14 days. With a clutch size of between 4 and 6 eggs, young will take 24-30 days to fledge. Woodpeckers will establish their own territories by the start of their second year. Species do not migrate but may wander a couple hundred miles north or south in search of food and suitable nest sites.

Colaptes auratus, Northern Flicker by Phil Myers

One of the few bird species that do not sing, woodpeckers have simple calls that may sound like a rattle or a whirring noise. Drumming is also widely used for marking territory, attracting mates and communication. Both males and females drum. Drumming is performed preferably on hard surfaces so sound carries a good distance. This may include hard-wood trees as well as barrels, downspouts and sides of houses. Drumming can be easily distinguished from the sound made when drilling for food by its very fast tempo.

Dryocopus pileatus, Pileated Woodpecker by Phil Myers

Bills, heads and bodies are all uniquely adapted to support drumming and wood chiseling. Tails are very stiff and the two central feathers are pointed, reinforced with central ridges and have inward curved barbs with strong muscles to hold the bird upright and steady against a tree trunk. Feet have four toes, two pointing forward and two backward to provide a solid platform for an upright stance. Bills are stout, straight and chisel shaped to break wood apart. Species that aggressively excavate tree trunks include downy, hairy and pileated woodpeckers. These birds have extra feathers covering their nose to filter out sawdust and eyelids that close right before each strike of the bill.

Melanerpes erythrocephalus, Red-headed woodpecker by Phil Myers

As a group, woodpeckers have stable populations. They may be locally declining in areas where there is heavy pesticide use on ant species, one of the staple food items for several species, particularly flickers in the Eastern U.S. Competition from starlings for cavity sites may affect small populations. Some birds are dependent on large woodland tracts, but evidence for the woodpecker populations in our area indicate that none are in danger.

Nocturnal Animals

I like to get outside every day, but with these really hot days oftentimes I go for a walk late in the evening as things start to cool off. It is quieter and pleasant – but not too quiet. There are still lots of sights and sounds of nature at night. What are all of these animals that are out well into the night? And why are they not active during the day? And how do they see in order to do anything?

All animals use their senses to find food and shelter and avoid predators. Nocturnal (active at night) animals have heightened senses or special adaptations that help them survive in the dark. Sight is the sense that humans rely on the most, but it is not as useful when there is very little light available. Structures in the eye called cones allow animals to see color. Other structures called rods are used to gather light. The more rods in the eye, the better an animal can see overall, and especially at night. Some nocturnal animals such as raccoons, bobcats, owls and rabbits have many more rods than daytime animals allowing them to see much clearer in the dark. And many of those same animals have very large pupils that let in more light.

Large eye pupils on Eastern Screech Owl,*Megascops asio* by Greg Hume

Owls, opossum, deer and fox have much better hearing than most other animals. Hearing adaptations include having larger ears, many of which are cup-shaped in order to gather more and fainter sound waves. A hertz (hz) is a unit of measure for soundwaves. We can hear between 20hz and 20,000hz, whereas a mouse can hear from 1,000hz to 100,000hz. This means the mouse can detect an insect moving under the leaves from several yards away. Another adaptation of many nocturnal species is asymmetrical ears. They can hear from each ear independently, allowing them to triangulate where the sound is originating. Triangulation can help identify the direction the sound is coming from – right, left, up or down, as well as how far away the point of origin is.

Echolocation, a specialized version of a hearing adaptation is used by bats in our area. The bat produces a high-pitched sound wave that is returned to the bat’s ears after it has bounced off another object. Bats use echolocation to determine an object’s size, shape, distance and whether the object is moving or stationary. If the object is moving, the bat can also determine the direction. A bat can emit calls at a slow rate of 15-20 per second up to 200 per second when closing in on prey.

Coyote, Yosemite 2009 by Yathin S Krishnappa

Smell is another sense used for hunting. Fox, raccoon, coyote, mink and skunk all have enhanced nasal passages and brain centers for detecting and identifying odors. They have enhanced abilities to detect fainter odors and to be able to identify their origin to a finer degree. Nighttime air is often still and moist, allowing scent molecules to linger longer, enabling an animal to better locate food as well as detect predators.

Two views of Wellington, New Zealand, taken same night by Science Learning Hub–Pokapū Akoranga Pūtaiao, University of Waikato, http://www.sciencelearn.org.nz

All of these differences make life easier at night for nocturnal species. There are fewer predators, and it is easier to hide in order to avoid becoming a meal. But there is also less competition with other predators to find food, and enhanced senses to create unique hunting strategies. Light pollution can be a huge negative influence on true nocturnal species. Constant night light sources affect species dependent on day-night triggers for behavioral patterns. Migration patterns may be disrupted; insects are attracted to light/heat sources only to be trapped and/or killed; reproductive cycles can be altered. In the green frog, an Illinois native, males will call less and move around more making it much harder for females to find and mate with them.

You can learn more by spending some time enjoying the nighttime yourself. Use your senses to detect what is active in your own backyard after dark. Try observing with and without a flashlight or your porch light. Give other species time to get comfortable with you being outside by spending 5-7 minutes sitting quietly before moving around. Use a cell phone to record what you are hearing, and write down your observations and experience as soon as you can after returning indoors. Consider repeating this activity on a rainy night or a winter night, and keep a journal of your experiences to learn and better understand the habitats where you live.

Backyard Activities

During the summer, I take a walk around the yard every day to observe the dozens of insects in the garden. It is fun to identify the species and watch the activities they are engaged in and learn how they keep my backyard healthy and looking so wonderful. Here are some of the insects I recently observed.

Cabbage White Butterfly, *Pieris rapae* by Ypna

Bees, wasps, and flies often visit ‘Walker’s Low’ catmint, Nepeta faassenii, a purplish, low-spreading perennial that flourishes in bright sunny locations. I most often see honey bees, Apis mellifera, and cabbage white butterflies, Pieris rapae, visit the catmint. Both insect species are taking nectar for food from the catmint. They don’t stay long in any one place, and flit constantly from one flower stalk to another, taking small sips and moving on.

Another hotspot for insects is in the vegetable garden. We have tomatoes, peppers, beets, carrots, parsley and dill, Anethum graveolens, an annual herb in the celery family used as a spice for flavoring food. Dill is also a host plant for the Eastern Black Swallowtail Butterfly, Papilio polyxenes. After the eggs hatch, the earlier stage caterpillar is black overall, with sharp orange spikes covering the body and a white “saddle” in the middle. As the caterpillar matures, it will lose the spikes, turn light green with yellow spots and whitish stripes, then enter the chrysalis stage and eventually emerge as an adult butterfly.

Another winged insect you may see, the Crane Fly, a member of the Tipulidae family, has a bright orange body and glowing green eyes. These insects can be found in moist woodlands or around bodies of water including a creek or pond running through your backyard. They lay their eggs in water or moist environments, and the larvae live in the top layers of soil. The larvae help to break down organic material in soils while the adults are an important food source for spiders, fish, small amphibians and birds. The typical lifespan for an adult is only 1-2 weeks.

Monarch, *Danaus plexippus* by Captain Tucker

Monarch butterflies, Danaus plexippus, are starting to appear daily. The monarch is the State Insect of Illinois, and it is found throughout the state in all habitats except deep forest. Up to three generations are born each summer, and the last generation in late summer / early autumn is migratory, flying to overwintering sites mainly in the high altitude regions of Mexico. Monarchs are dependent upon the many species of plants in the milkweed family, Asclepiadaceae. Eggs are laid on leaves and the caterpillars feed exclusively on species of milkweed. In recent years, we have seen a decline in the number of milkweed plants everywhere in Illinois, but you can help monarchs by planting them in your own yards and encouraging local business and government to do the same.

*Popilla japonica*, Japanese Beetle by DonArnold

The Japanese beetle, Popillia japonica, can be found on many plants in the garden. It is an invasive species that does very little harm in its native country, but is a pest of over 300 species of roses, grapes, linden trees and numerous other plants. The adults eat everything between the veins of the leaves, then the plants can no longer create their own food. Japanese beetles display iridescent copper-colored wings folded over their backs behind a dark green head. Several insects and parasitoids have been brought into the U.S. to control these beetles, with limited success. Traps have also been developed, but data suggests that these merely entice the beetle to a host plant.

Green bottle fly, *Lucilia sericata* by DonArnold

The common green bottle fly, Lucilia sericata, also known as a blow fly, is a member of the fly family, Calliphoridae, comprising over 1200 known species. Members of this family occur worldwide in almost every location that includes humans. Adult flies feed on carbohydrate-rich nectar in the garden, as well as any decaying meat or garbage. Dumpsters and garbage containers accessible from outside may attract flies in huge numbers. Eggs are laid on carrion and larvae feed on the carrion. The time period from egg to adult can be between 2 and 4 weeks, and a female may lay 10-15 clutches of 200 eggs each in her lifetime. The best control for these insects is to keep refuse covered at all times.

Bullfrogs

Croak! Croak! Croooooak! I live on a pond, and for the last week has it has belonged to the bullfrogs, Rana catesbeiana. The bullfrog is the largest species of frog in North America, and the ones in my pond are no exception. Bullfrogs are green, yellow-green or brown with dark splotches on the back and dark leg bands. The tympanum, or eardrum is immediately behind their eye. On male bullfrogs, the tympanum is larger than the eye, and their throats are pale turning to dark yellow when breeding; on female bullfrogs, the tympanum is the same size as the eye and their throats are whitish.

Their preferred habitat is still, permanent bodies of water, with plenty of submerged and emergent vegetation. Bullfrogs hibernate over the winter in the mud at the bottom of these permanent pools. They like warmer water and generally will not emerge in spring until water temperatures are in the 15^C (60^F) range.

Bullfrog in submerged vegetation, by DonArnold

Breeding, mating & calling activities start in late May and extend well into July. Bullfrogs are normally active from early evening all through the nighttime hours, and may extend activities into the daytime. They are most active on warm nights. Males sit in the shallows or along the banks and create a low-pitched brrr-rum call to find a mate. Males are territorial establishing an area roughly 5′ to 20′ in diameter that they actively defend from encroachment by other males. Within the same pond, several males may have bordering territories, and neighbors will also aggressively object to a new frog attempting to take over an existing territory. Larger males will establish themselves in the choicest sites hoping to lure females to an area good for egg-laying.

Bullfrogs – The Confrontation, by DonArnold

The female deposits from 5,000 to 20,000 eggs in a thin-mucus covered, floating mass that may be from a foot to three feet in diameter. Eggs will hatch in three to six days into tadpoles. Tadpoles spend from one to two years living in the pond, feeding on algae or decaying material until metamorphosing into froglets in their second or third summer. Bullfrogs become sexually mature in two to four years, and their lifespan is six to eight years.

Bullfrogs will eat nearly anything they can swallow including fish, snakes, turtles, other frogs, birds and small mammals, but the majority of their diet consists of invertebrates including dragonflies, beetles, insects, spiders, snails and crayfish. Bullfrogs are also prey for fish, snakes, turtles, herons, otters, racoons and mink. They are extensively hunted by man for the food industry, especially frog legs. If threatened, they are equally comfortable on land and water and may flee to either habitat. When caught, they emit a loud wailing scream that often times startles the predator and allows the bullfrog to escape.

In recent years, the pond behind my house has been naturalized with native vegetation. The bullfrog population as well as many other species have responded very favorably to these efforts. However, in many other areas, habitat loss, water pollution and pesticide runoff have all been factors in the declining populations of bullfrogs and other amphibians. Removal of shoreline vegetation for real estate or recreational development has damaged a number of breeding sites. You can help by supporting efforts to keep local ponds, lakes and other wetland sites natural and undisturbed.