Wrens are extremely common throughout the western hemisphere. These birds build their nests in many unusual places, including old boxes, discarded cans, and inside sheds and garages. It's not unusual for humans to find abandoned baby wrens or babies that have fallen from trees. Caring for a wild baby bird can be tricky, but the right supplies and background knowledge make it much easier.
Examine the baby bird. If it has no injuries, place it back in its nest. Wrens often hide their nests, so this may be difficult. If you can't find the nest, place the bird in a small container, such as a berry basket, lined with newspaper. Place the basket in dense shrubs or undergrowth.
Observe the area. If the parents don't return to interact with the baby, you may assume that it is an orphan.
Take the bird to a wildlife conservation group. Injured baby wrens or wrens without parents should be cared for by professionals. If possible, contact your local wildlife group and have them care for the baby wren. If a group is not available, take the bird inside for home care.
Provide a warm nest. Line a shoebox with newspaper or paper towels. Cut small holes in the lid of the box, and place the baby bird inside. Keep the box covered and away from children and pets. Provide warmth with a desk lamp fitted with a high-wattage incandescent bulb. Avoid fluorescent bulbs, which do not provide enough heat.
Feed baby wrens regularly. Baby birds need food every 15 to 20 minutes while the sun is shining. Mix one part protein, such as soaked puppy kibble, beef baby food or prescription dog food, with two parts high protein baby cereal or powdered grain meal to produce a thick liquid. Feed the baby via eyedropper or syringe.
Teach the bird to eat insects. As the baby grows older, provide small crawling insects, such as mealworms, at each feeding. Press an insect against its beak to encourage a feeding response. Eventually, the baby wren will learn to pick them up. Don't worry if it takes some time--feeding is instinctive.
Provide a larger box as the bird grows. Older birds need more space and will be uncomfortable in a shoebox. Take the bird outside in a cage or box from time to time to get it used to the outdoors. Do not allow the bird to fly freely in the house.
Release the baby wren. When the baby is old enough to fly and feed itself, place its cage or box in a familiar outdoor area with no roaming dogs or cats. Leave the lid or door open, and allow the bird to fly away as it chooses. Leave food in the cage for several weeks, so that the wren has time to adjust, but don't handle or talk to it. Eventually, the wren will become wild again.
Baby birds require constant care and supervision to survive. Do not get food under the baby bird's tongue, as it can choke. Keeping wrens as pets is illegal in most areas.