Q. I saw a photo on Facebook of a rattlesnake with its head looking up at the base of an oak tree and its enormous body stretched out in the leaves on the ground. I know it was a rattlesnake because it had a long string of rattles. Do rattlesnakes really do that or was the image photoshopped?

A. I do not know if we are talking about the same photo, but I have seen one of an adult timber rattlesnake posed in the manner you describe, and it is real. John Hewlett at Murray State University in Kentucky used radiotelemetry to track movement patterns of snakes. Squirrels are a major part of the diet of timber rattlesnakes, which have been reported to lie in wait at the base of large oaks or hickory trees frequented by their favorite prey. The snake’s body pattern serves as camouflage effective enough to fool a squirrel looking down on a woodland carpet of colorful autumn leaves and descending to gather acorns or hickory nuts. John’s photography confirmed this unusual behavior for timber rattlesnakes, the most widespread large rattlesnake in the eastern United States.

Q. Do any birds besides owls fly at night?

A. Short answer, yes. Several birds other than owls are nocturnal, including black-crowned night herons and whip-poor-wills. But most nighttime flying is done by small birds, such as sparrows and warblers, during fall and spring migrations. Lots of migrating birds fly at night. Various reasons have been proposed for why birds fly at night instead of during daylight. One reason is that they are less vulnerable to aerial predators such as hawks and falcons when traveling under cover of darkness. Another reason is that higher altitudes are usually calmer at night. Consider also that they are more likely to find insects and seeds while foraging during daylight hours. Forage in light, fly at night.

Certain birds have been reported to use celestial cues and the earth’s magnetic field to determine compass directions. Finding their way on a clear night is not a problem, and some birds navigate using the north-south magnetic field. Studies at the University of Michigan confirmed birds’ use of stars by experimenting with indigo buntings in a planetarium. When the planetarium’s sky view was shifted, buntings ready to migrate were found to orient by the stars. Many migrating birds likely determine their travel direction to some degree by celestial and magnetic orientation. Conservationists note that with the increase in human populations and ground lighting, nocturnal flight has become hazardous for migratory birds. They can become disoriented by or even attracted to lights and can collide with cell towers and buildings.

Q. I saw a couple of fairly large (size of a football) turtles basking on a log in a lake near Tuscaloosa, Alabama, the day after a near-freezing night. Even though it was a sunny day, it was still pretty cold outside. Isn’t that kind of unusual? Don’t turtles hibernate when the weather gets cold?

A. Aquatic turtles in Alabama and other parts of the Southeast become dormant during cold weather, but many are active during warm spells on a sunny winter day when they can warm up by basking. Most likely, the turtles you saw were red-eared slider turtles, which are the most common species in Alabama lakes, oxbows and river margins. But cooters, which are similar in appearance to sliders, bask in the same habitats. Snapping turtles and softshell turtles will occasionally crawl onto logs to sun themselves but are less likely to do so in cold weather.

A notable fact about turtle populations in the Southeast is that the Mobile Basin has more different kinds of turtles than any other region in the world except for area in southeastern China with similar habitats. Alabama and Mississippi each have more species of turtles than any other state and more than most countries in the world.

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