Often our hearts are bigger than our brains when we see an animal in pain.  Even a family pet who trusts completely will lash out when the pain is great enough.  With wild animals the danger is greater.  The animal does not know you and may see you as a bigger danger than the pain it suffers.  There is also the chance that any wild animal may carry rabies.  If you insist on helping, do it with caution.  Never pick up an injured animal with your bare hands.  Have a protective coat, blanket or other cover to put over the animals face and claws.  If you have heavy gloves, wear them.  The covering over their heads sometimes calms the animal since it can no longer see you as a danger.  If possible move the animal to a safe place (such as the side of the road if it has been hit by a car) and call for help to the SPCA or animal police.  There is less chance of doing more damage if the animal is moved as little as possible.  If calling for help is not an option, gently put the animal in the backseat of your car and take it to the nearest vet or shelter.  If helping wild birds who are hurt, do NOT wrap them in blankets or extra warmth of any kind.  Quickly place the bird in a dark place, such as a box for larger birds or a plain brown paper sack (no plastic please as it suffocates the bird) and get it to a vet or shelter as soon as possible.  Here in Sarasota we have a Bird Sanctuary.  They taken in all types and bring them back to health.  They are then freed if they can care for themselves in the wild.  If they cannot, they become a permanent part of the sanctuary family.