Maybe you have noticed those great big birds soaring high in the sky and you would like to know more about them?

This test contains interesting details, but some of them are pretty gory – so you might not want to read this while eating dinner.

* Do turkey vultures have a good sense of smell?

Yes, their olfactory lobe is particularly large compared to other animals. That is the part of the brain responsible for processing smell. This helps them to find carrion below the forest canopy and detect the smell of ethyl mercaptan, a gas produced by the beginning of decay in dead animals.

* Why do turkey vultures urinate on their legs?

It serves two purposes. Because the vultures cannot sweat, they cool themselves using a process called urohydrosis. In the summertime, wetting the legs cools the vultures as the urine evaporates. Also, the urine has a high uric acid content that acts as a sanitizer, killing any bacteria the birds pick up while stepping on their food. This gives them a certain tolerance to microbial toxins (such as botulism) and even certain poisons used to kill coyotes and ground squirrels. The bird’s droppings are also disease-free, and since this is so unusual, scientists are studying their digestive cleansing process.

* Why do some turkey vultures have a red head and others a black head?

The juveniles have a black head, while mature birds have a red head. Females and males are identical in appearance, except the female can be a little larger.

* Why does the turkey vulture have a bald head?

Since it eats carrion and must stick its head inside the carcass to reach the meat, a feathery head would capture too many bacteria. After mealtime, the turkey vulture perches in the heat of the sun. Here, whatever managed to cling to its head will dry and fall off.

* What is the call of a turkey vulture?

That’s a trick question. They do not have a voice box; they can only hiss and grunt.

* Do they eat only carrion?

No, they eat plants, live insects and other invertebrates or washed-up fish along rivers and oceans. Each bird eats about 111 pounds of carrion per year.

* What technique do they use to defend themselves?

The turkey vulture’s most important form of defense is to vomit. Even the babies learn to do that, early in life. They do not have many predators, but the time spent at the nest is the time when they are most at risk. When attacked, they cough up some semi-digested meat. The foul-smelling substance will deter most creatures from raiding the nest. Also, it will sting the eyes of the animal if it is close enough, because the vomit is highly acidic.

* Do they have strong talons?

No, they have very weak feet, more like chicken feet. They can walk and hop, but that is all.

* Are turkey vultures aggressive?

No, they are very gentle, shy birds that can easily be intimidated by a much smaller bird like a crow.

* What is the “horaltic position?”

You will see this in the early morning. They spread their wings out wide in order to dry off the morning dew. In order to fly, they need to be completely dry. They also use the sun to warm up their body and to bake off bacteria.

* Do turkey vultures often flap their wings?

No, they flap far less often than other birds. In the morning, after drying their feathers in the sun, you’ll see their clumsy and laborious takeoff. After that, they circle upward, searching for pockets of warm, rising air called thermals. Once they find one, they allow it to carry them upward in rising circle. Once they reach the top of the thermal, they dash across the sky at speeds near 60 mph, losing altitude until they reach another thermal … and start the process all over again.

They can actually soar for six hours without flapping their wings. While soaring, they hold their wings in a V shape to take advantage of the thermals to keep soaring. This flight pattern makes them easy to identify. Also, they often tip slightly from side to side, using the tip of their primary feathers to change their direction. At the end of the day, you will see another clumsy-looking landing. They often crash through the leaves and branches to reach their roosting spot.

* Why do turkey vultures spend the night in a roost?

A roost is a meeting place. Turkey vultures gather there one hour before sunset and leave the roost about one hour after sunrise. I had such a roost in my backyard for many, many years until one large branch fell down and the environment was so disturbed that the turkey vultures abandoned the roost and chose another tree.

Your guess as good as mine as to why they gather at the roost. They might feel there is safety in numbers, spending the night together. Roosts are used for many years, so the parents teach the young ones where it is. They seem to be very gregarious, so they might have a need to belong to a group, the patriarch keeping the young ones in their place. The nest is never at the roost but in a different place, away from the group.

* Do all turkey vultures migrate?

In Southern California, that is a tricky question. The turkey vultures in my back yard always migrated during the last week of September and returned during the first week of January. However, there is a population of turkey vultures which can be seen in Southern California all year around. It is understood that those are coming from the north and find the climate here mild enough to spend the winter. There might be a population along the coast, where the weather remains constant, that does not migrate because they do not have incentive to do so. Without tagging or banding every bird and checking their whereabouts, it is impossible to know where they are going exactly, so migration remains an elusive topic.

* Where can I see one up close?

If you want a close look at a turkey vulture, I can recommend a little visit to the Placerita Canyon Nature Center where you can meet Apollo, our resident turkey vulture, in one of the enclosures on the patio.

Evelyne Vandersande has been a docent at the Placerita Canyon Nature Center for 28 years. She lives in Newhall.