Turkey vultures picky eaters of rotten meat

The ruckus of magpies and ravens caught my attention as I walked up the road. As I approached, the magpies, ravens and eagles flew off but the large, red-headed turkey vulture kept its place on the limb above the scavenged deer. 

Without a doubt, I could see why the turkey vulture was named after a turkey--the red, featherless, wrinkled head. One ugly bird. 

Turkey vultures only spend the summer in North Idaho. Come autumn, they migrate to Mexico, Central America or South America.

The featherless head serves the turkey vulture well when it buries its head deep into a carcass to pull out meat. Instead of needing to clean feathers, the turkey vulture allows the sun to bake any parasites or dried bits of meat off its head.

Turkey vultures primarily feed on carrion, including roadkill, dead livestock and fish carcasses. They will also ingest maggots, worms and other invertebrates while feeding on carcasses. While sight may help them find carrion, their noses are the primary detectors of the next meal. Turkey vultures possess an extremely strong sense of smell and can smell a rotting mouse from 200 feet up in the air. 

Even though they are part of nature’s clean-up crew, turkey vultures are picky eaters by preferring “freshly dead” meat. Turkey vultures usually won’t find fresh carrion on the day it was killed because there isn’t enough odor. They almost always find the carrion on the second or third day when it begins to rot. Often by the fourth day, they will rarely visit the carrion because the meat is too rotten to eat. 

Eating rotting meat requires a strong stomach and turkey vultures combat this with powerful enzymes in their digestive juices that kill bacteria--even bacteria that causes serious food poisoning. 

Not only does the turkey vulture clean up nature’s freshly deceased, it kills the bacteria and diseases within the animal. Researchers have found that the turkey vulture’s scat contains no trace of diseases present in the carrion. 

Turkey vultures will roost for more than two days if it is raining

Few animals harass turkey vultures and their nestlings. If an animal doesn’t heed the loud, hissing warnings of being too close, the vulture can projectile vomit partially digested rotten meat up to 10 feet away. 

Predators also stay away from turkey vulture nests because of the repulsive smell of regurgitated rotted meat fed to the young. 

Turkey vulture nests are the most basic of nests--a spot to lay eggs. They lay one to four eggs with no nesting material in crevices, caves, stumps, hollow trees, cliff ledges or on the ground. Occasionally, they will lay eggs in an abandoned stick nest of a large bird.

Young vultures are noisy like other young birds but the adults are quiet birds. Turkey vultures lack the same vocal structures of other birds and can only hiss, grunt and make barking sounds. 

Unlike other birds that prey on meat, turkey vultures have weak legs and feet because they feed on dead meat and don’t capture prey. Their legs aren’t strong enough to carry food away from the kill site, so they gorge themselves until full. Then they fly to a limb and sit sleepily while they digest the meat. 

Carrion can be few and far between but turkey vultures are amazing gliders. With their six-foot wing span, they can ride thermals and mountain updrafts for nearly six hours without flapping. Compared to other soaring birds, the turkey vulture holds it wings in a deep “V” as it flies. 

Once the sun has warmed the land to create thermals, turkey vultures take to the skies to sniff out carrion at just the right stage of rotting. Scavengers don’t live a glorious life but the world would be dirtier without them. 

Note: Published in the Bonners Ferry Herald on Aug. 29, 2013.

Speed of lightning incomprehensible

Flash, boom, rumble. The night sky lights up for an instant before the booming thunder overpowers all other noises. Again and again, the lightning and thunder flash and boom until the thunderstorm passes over. 

While thunderstorms can occur year round, they are most common in spring and summer in the afternoon and evening because of unstable air. The hot air rising from the Earth’s surface creates unstable air masses visible in the form of cumulonimbus clouds. 

The rapidly growing towering thunderheads create an imbalance of electrical discharge that is responsible for lightning. In the cumulonimbus cloud, rising ice crystals and falling hail collide and free electrons. The ice crystals gain a positive charge and rise to the top of the cloud through convection while the hail assumes a negative charge and sink to the bottom of the cloud. 

Cumulonimbus cloud

Only an electric current, in the form of lightning, between the two charged areas can balance the difference. Lightning within a cloud is called intracloud lightning and is the most common type of lightning.

Cloud-to-ground lightning occurs because the bottom of the thundercloud is negatively charged and the ground is positively charged beneath the cloud. The lightning begins by negative charges racing towards the ground (at about 200,000 mph) through a channel which is called a “stepped leader”. 

As the stepped leader approaches the ground, positive charges rise through trees, buildings or people to meet the leader. These positively charged channels are called streamers. 

When the leader and the streamer meet, a negatively charged electrical current rapidly flows from the cloud to the ground and a visible flash of lightning streaks upwards through the channel at 200,000,000 mph. While lightning may appear to strike downward, we are actually seeing the return stroke of light streaking upwards. The entire process is completed in about 200 milliseconds. 

The air around a lightning bolt can be five times hotter than the surface of the sun

Each bolt of lightning can contain up to one billion volts of electricity and is extremely hot. During a flash of lightning, the air around the channel of electrical current can be heated to temperatures five times hotter than the sun’s surface, causing the air to rapidly expand and vibrate. This vibration is the thunder we hear.

Even though lightning and thunder occur at the same time, we see lightning before we hear thunder because light travels faster than sound. A good estimate on how far away a storm is from you is the difference in seconds between the lightning and thunder. For every five second difference between seeing lightning and hearing thunder, the storm is one mile away. 

Lightning can strike more than 10 miles away from a cumulonimbus cloud through “positive lightning”. Positive lightning is a type of cloud-to-ground lightning that originates in the positively charged top of the thundercloud. The positive charged stepped leader seeks out negatively charged ground away from the storm cloud (since underneath the storm the ground is positively charged). The reverse flow of negative current from the ground to the cloud is stronger and more destructive than regular cloud-to-ground lightning. 

If you can hear thunder, there is danger of a lightning strike nearby. Thunder can be heard up to 15 miles away in quiet areas. Lightning can be seen 100 miles away, which allows for some spectacular storm watching at night when a line of thunderstorms is passing nearby.

Note: Published in the Bonners Ferry Herald on Aug. 22, 2013.

Wasps prolific this year with dry weather

Warmer, drier weather this spring not only helped gardeners and farmers but also stinging insect populations. Cold, rainy weather in April and May can reduce nest success because queens have a harder time building a nest and collecting enough food for their offspring. Wasps, yellow jackets and bald-faced hornets are plentiful this year in part to the nice spring weather. 

European paper wasps resemble yellow jackets but are slimmer and have longer legs

Bees and wasps are both stinging insects but they are different. The body of a bee is partly covered in fine hairs, such as a bumblebee. The body of a wasp is bare and shiny. 

Bald-faced hornets, yellow jackets and paper wasps are all species of wasps. Bald-faced hornets are a species of yellow jackets.

Bees have fine hairs on their bodies

Each wasp has distinct characteristics that help differentiate it from other wasps. All wasps are more slender than bees.

Yellow jackets are black with irregular, jagged yellow bands while bald-faced hornets are black with a pale yellow face and a few whitish markings on the abdomen. Paper wasps resemble yellow jackets in color but are slimmer and have longer legs that hang down during flight. 

Another difference is the nests. Bald-faced hornets build large football-shaped nests in trees with a single opening on the bottom. Yellow jackets typically build the same type of nest as the bald-faced hornet but it is underground in animal burrows, stumps or any cavity. 

However, the aerial yellow jacket builds a nest above ground like the bald-faced hornet but is more likely to build it on roof overhangs or protected building surfaces. Aerial yellow jackets don’t add leaves and twigs to the outer nest walls like bald-faced hornets. 

Inside of an aerial yellow jacket nest

Aerial yellow jackets build nests similar to bald-faced hornets

Paper wasps build umbrella-shaped nests with the comb visible from the bottom. The nests are smaller than other wasps and are built in protected places, such as light fixtures, eaves, utility boxes and patio furniture.

While yellow jackets are the most blamed for stinging, paper wasps are actually the most common stinging pest in Idaho because their nest sites are closer to human activity. Paper wasps are relatively docile compared to yellow jackets when their nest is disturbed but they will still sting to defend their nest. Only female wasps sting because the stinger is an egg-laying tube modified to inject venom.

In late summer and fall, wasps (especially yellow jackets) tend to be more easily provoked because natural foods are scarce and they are raising the new queens in their nests. Only the queens overwinter to begin new nests in the spring.

Food sources vary throughout the season but wasps are highly beneficial to the ecosystem. Bald-faced hornets feed almost entirely on living insects including yellow jackets. Paper wasps prey on caterpillars, soft-bodied leaf-feeding insects and nectar.

Bald-faced hornet nest

Yellow jackets primarily feed their offspring insects, such as caterpillars, beetle grubs, grasshoppers, flies and spiders. Adult yellow jackets ingest some of the prey’s bodily fluid but feed mainly on nectar. They do not produce honey like bees. As insects become scarce, yellow jackets feed on dead protein and sugary food and, thus, become a picnic pest.

With a primary food source of insects, bald-faced hornets and paper wasps tend to be less of a picnic pest. 

The threat of stinging, whether at picnics or while mowing the yard, will be present until cold weather kills all but the queens.

Note: Published in the Bonners Ferry Herald on August 15, 2013.

Insects instigate abnormal growth on plants

Odd growths on plant leaves or stems ranging from tiny bumps to red, spiny growths to pinecone-like growths on willows are a unique plant/insect relationship. These growths, called galls, typically don’t harm the plant but are extremely beneficial to the insect.

In the plant/insect relationship, the insect lays egg(s) in a plant and the resulting abnormal growth in the plant creates a gall. Typically ranging from one-sixteenth of an inch to over two inches, the gall grows with the egg and larva until it pupates and emerges. 

Spiny rose galls containing gall wasp larvae

Each insect and plant combination results in a specific type of gall. If several different insects lay eggs on the same plant, different galls are produced. Over 2,000 insects produce galls in the United States, of which 1,500 species are wasps or gnats. Organisms that instigate galls include beetles, moths, aphids, flies, wasps, bacteria, mites, fungi and nematodes (parasitic worms). 

Generally, an insect targets one plant species to lay her eggs on which results in a gall of a certain size, shape and color. Galls can be round, oblong, egg-shaped, spindle-shaped, bottle-shaped or an odd-ball shape. Gall flies lay their eggs on willows and produce a pinecone-looking gall. Other specific galls are called oak apples, honeydew and ambrosia galls.

Insect gall makers lay their eggs in different parts of the plant: buds, leaves, stems or roots. Gall insects are more attracted to certain plant families, such as willow, rose, daisy and oak. Goldenrod is another plant that certain insects target for galls.

Gall on a lodgepole pine

Generally, insects lay the eggs in the spring during the plant’s accelerated growth period. Mature plant parts don’t react to gall-making insects.

The exact mechanism for gall production is uncertain but scientists believe the growth results from a chemical released by the eggs and larvae and/or mechanical damage to the plant. The gall begins forming through increased production of normal plant growth hormones, resulting in localized plant growth.

After the egg hatches, the larva continues to release the chemical that stimulates plant growth and keeps the gall growing to match its size. The mass of tissue around the larva is a defensive reaction by the plant to contain the larva from eating the rest of the plant. To the larva’s benefit, the gall is edible and highly nutritious with the concentrated new growth. 

Spiny rose gall spines mimic those of the rose plant

Some larvae spend the majority of their lives within the gall. Many overwinter within the gall, pupate in the spring and emerge as adults to begin the process all over again. Wasps, moths and flies (all possessing chewing mouthparts) chew their way out  of galls when adults. Other species almost chew their way out as a larva (when they have chewing mouthparts) and then force their way through the remaining thin layer after they pupate.

Overwintering larvae may be protected by the elements but not from predators. Downy woodpeckers and black-capped chickadees are a few predators that hone in on the conspicuous galls for a protein-rich meal in winter. 

Once empty, galls become shelter for other insects, sometimes even nurseries for other insect eggs. Whether empty or occupied, galls provide visible sign into part of an insect’s life that often goes unseen. 

Note: Published in the Bonners Ferry Herald on Aug. 8, 2013.

Bats only mammal capable of true flight

As twilight faded, all eyes watched the bat houses mounted on the side of the building. Slowly, the bats flew one by one from the bottom of the bat houses into the woods or swooped overhead searching for insects.

The night before, staff and volunteers at Kootenai National Wildlife Refuge counted nearly 1,100 bats emerging from the bat houses and eaves of the building. After a recent bat survey, biologists identified 11 of the 14 bat species that exist in Idaho at the Refuge. 

Nearly 1,100 bats live in these two bat houses at KNWR

The diversity of bats at the Refuge is most likely because of the variety of habitat in the Kootenai Valley, including different forest types, cliff faces, rock crevices and buildings. Each bat species seeks a specific type of habitat to roost and some roost in colonies while others roost individually. The maternity colonies of the little brown myotis can number up to 1,000 bats.

Over 20 million bats live in the Bracken Cave in Texas and eat over 250 tons of insects every night. Bats can eat about a third of their body weight each night. Pregnant and lactating females can eat up to their body weight every night. 

To consume the equivalent of a bat, a 150-pound person would have to eat 96 Big Mac’s every day.

The majority of bats in Idaho eat insects but other bat species around the world eat fruit, nectar, meat, fish and blood. 

Some bat species that fall from their roost cannot take flight off the ground

With insect populations beginning to decline in the fall, bats either hibernate or migrate for the winter. Two bat species found in Boundary County migrate south: the silver-haired bat and the hoary bat. The remaining bats in Boundary County hibernate in hibernaculum, either individually or in colonies. Disturbances can greatly decrease the chance of survival for the bats as they utilize precious energy bringing their body up to functional temperatures.

The migratory hoary bat is the largest bat in Idaho and in Boundary County at a weight comparable of 11.5 pennies. The smallest bat at the Refuge is the western small-footed myotis at a weight of 1.75 pennies. The largest bat species in the world is the large flying fox (Pteropus vampyrus), which has a wingspan of 78 inches. 

Bats are unique for their size. They are the slowest reproducing mammal on Earth for their size (think of how many young a mouse produces each year) and they have the longest life span for their size (average of 15 to 20 years). Bats don’t typically reproduce until their second or third year and usually produce one offspring each year.

The pups are extremely small when they are born but have strong legs and claws because they have to hang in the roost while the mother bat is gone. 

Bats that have fallen from their roost (once capable of flight) can sometimes fly from their position on the ground. Other species cannot take off from the ground and will crawl over to a tree or something they can climb in order to gain altitude to take off. If a pup falls from a roost and isn’t capable of flight, nature takes its course.

A bat biologist identifies a bat during research at Kootenai National Wildlife Refuge

Bats are the only mammal capable of true flight. Two thin layers of skin stretch over finger bones to create the wings. The feeling of the skin is likened to the skin on human eyelids. 

Being a nocturnal creature, the best time to see these unique mammals is when they take to the dimming sky at twilight to feed on insects.

Note: Published in Bonners Ferry Herald on August 1, 2013.