When birds sleep, how do they not fall off the branch, wire, etc.?
337419
When perching birds sit, a tendon on the backside of the ankle automatically flexes locking their toes around the branch. With feet locked, sleeping birds don't fall. As the bird stands up its feet release.
710541
I don't think porcupines hibernate, they will use dens, and tree hollows to sleep in.  I know they can climb because I once was out hiking and found a mother and her baby up high in a tree.
350056
Typically they are protected and as the guy above said why would you want to?\n\nWhy don't you post another questions like, "How do I keep woodpecker from beating holes in my cedar siding and waking me up at 6:00 AM every morning?"\n\nHint - a product called Tangle-foot
63919
Because of the way their legs are built.\nThe tendons in bird's legs are arranged as a pulley-rope system so that the weight of the animal pulls on these tendons and keeps their fingers closed at rest. Thus they do not require voluntary muscle action to maintain their grasp on branches.\nThis is specially characteristic of songbirds. Others may rely on nests, platforms or other types of dwellings
789781
they are dead.\n\njust like dead tree limbs, they fall off in time.\nit's called gravity.\n\nthe tree goes dormant, the leaves are not needed any longer for this year.\n\nthe leaves are dead and gravity will pull them to the ground
394418
This question on how to repel birds has come up a lot now that bird flu is in the news.  They sell high voltage strips that you can have installed on the top of the tower.  When the birds land they get a small shock.  It doesn't hurt them; however, they will leave the tower.  Also considering your an airport, birds can create a lot of damage to an aircraft.  I've heard of people hiring hawk trainers to come to the airport once a week.  The hawks feed on a bird and the birds leave the area.
796035
It's not zero gravity, it's microgravity actually. They lose bone mass and muscle tone when they are subjected to this condition because they are no longer applying weight and resistance to their bodies so their bodies stop maintaining what it percieves it doesn't need.\n\nTo sleep they must strap themselves to the wall and to drink they use straws to keep the liquid from floating everywhere. The name of the game when eating is, get it all in your mouth.\n\nPeople can swallow in space as long as they have a normal, healthy GI tract because gravity isn't what keeps your food down. Your esophagus keeps itself flattened while it isn't in use and when you do swallow, the food or beverage is propelled down into your stomach by muscle ripples in your esophagus until it enters the stomach. The stomach has a sphincter muscle which acts as a valve up top that opens to allow food in and then closes to keep it in.\n\nThey can't take birds into outerspace because birds need the gravity here on Earth to swallow.
776602
i watched a tv program on this about birds that swarm and its all to do with a few factors ie all the birds are equal distance apart for flying purposes . no bird wants to be on the outside of the swarm or flock due to predator that target such swarms "falcons". so if you can visualise a bird has to have a zone around it to fly and it don't want to be on the edge.when the bird  near it moves to the centre of the swarm to stop being on the edge.the new bird that's exposed whether it be from the side above or below that bird will then move to gain cover in the swarm.hence the shapes you get and the sudden change in direction of the swarm you see in the sky.there is a a computer graphic program that runs this formula but i don't were to tell you to go for this.
652147
Well, they have no problem evading predators, and they're _very_ aggressive, no matter their size. \nBut hummingbirds simply cannot walk or stand on the ground. The reason is that their legs and feet are built in such a manner that they can only perch on small-diameter twigs (and cables, ropes, etc.). \nTheir legs are extremely short, and their small feet have long curved claws that do not allow them to walk or even hop. \nYou can see what their feet look like here: http://www.hiltonpond.org/images/RTHUHYMPerched01small.jpg
452976
It depends on the type of bird. Many bird fly to another area. Some birds take cover on the ground. Not all bird escape the wrath of a tornado. After a tornado struck our farm, my father was cleaning up the fallen trees in one of our corrals and found that the several members of the flock of turkeys that had been roosting in them were dead on the ground, having never left the trees in which they were roosting.
333005
TO GET SHOCK THERE SHOULD EXIST A SHORT CONTACT THAT MEANS IF BIRD TOUCHES ONLY PHASE WIRE OR NEUTRAL WIRE IT DOESNT GET SHOCH BUT IF IT ACCIDENTALLY TOUCHES BOTH THEN IT WILL DIE
5514
Yep, the dude above is right (I think, I didn't read it completely, too long I almost fell asleep!) but anyhow, it's not only the birds, for example if you fall from a plane or something and grab unto one of those lines then you wouldn't hurt yourself, but for example if you grabbed one line with one hand and another line with the other than that would be it for you...
1104792
When the bird perches on a live wire, her body becomes charged--for the moment, it's at the same voltage as the wire. But no current flows into her body. A body is a poor conductor compared to copper wire, so there's no reason for electrons to take a detour through the bird. More importantly, electrons current flow from a region of high voltage to one of low voltage. The drifting current, in effect, ignores the bird. \n\nBut if a bird (or a power line worker) accidentally touches an electrical "ground" while in contact with the high-voltage wire, she completes an electrical circuit. A ground is a region of approximately zero voltage. The earth, and anything touching it that can conduct current, is the ground. \n\nLike water flowing over a dam into a river, current surges through the bird (or person's) body on its way into the ground. Severe injury or death by electrocution is the result. \n\nThat's why a squirrel can run across an electrical line, but sadly die when its foot makes contact with the (grounded) transformer on the pole at wire's end. \n\nIt's also why drivers and passengers are warned to stay inside the car if it runs into a downed power line. Touching the ground with your foot would complete the circuit: Electrons would flow from the wire, into the car, and through you on their way into the earth. (Inside the car you are usually protected by the car's four rubber tires, which act as insulators between car and ground.) \n\nLikewise, birds can get in trouble with power lines if wing or wrist bones--or wet feathers--connect bare wires and grounds. \n\nRaptors (birds of prey) are especially likely to be killed by power lines, particularly in the western U.S. In wide-open plains and deserts, power poles are often the only high perches available for hunters like Bald and Golden eagles and Great Horned owls, who survey the landscape for prey and take off into rising wind currents. \n\nSuch large birds can easily contact two wires or a wire and a transformer with their great wingspread. And raptors can easily brush against a live wire while settling onto a (grounded) pole-top. Thousands are killed by power lines each year. \n\nHow to protect big birds? Power lines can be made less dangerous by widening the gap between conducting and ground wires, insulating wires and metal parts, and moving wires farther away from pole tops. And guards can be built around favorite raptor perches.
947772
These birds do not all have the same foot posture.  For example ostrich feet sit flat on the ground for walking while songbirds toes are designed to be able to curl and grip branches when they perch.  Birds like eagles have raptorial feet with long talons for capturing prey.  \nHope this helps
705306
none they work eccentrically in the down phase
19027
I think the scientific explanation is that this is a behavior trait that is hard-wired into their brains through the wonders of natural selection.  When animals are born (including people), their brains (and actually their entire physical bodies) are pre-programmed to do certain things.  They eat when they're hungry.  They "feel" hunger when they haven't eaten in a while.  They run when they're scared.  They feel scared when they see, smell, hear, or feel certain types of things.  Their hearts beat.  Their eyes blink.  They sleep when they're tired.  Having these characteristics gave them the ability to survive as a species and be around today to be observed by us.  Animals who had hearts that didn't "know" to beat automatically didn't last long.\n\nSo flying south for the winter is an instinct that allowed birds to survive.  The many birds who lacked that instinct had more difficulty surviving.
213392
still in the trees. deadwood, holes in branches etc. natural hidy holes. thats why itr is important to keep old forrests around - so the trees have little places like that for the birds