Birds sustain a number of injuries when hitting windows. Unfortunately, flight is not a sign of wellness. Anyone that slams into a hard wall going 20-30 mph, head first will sustain at least some injury (human or bird). Traumatic brain injury and concussion are the number one injuries. Also, bill fractures, eye injuries, internal injuries, hematomas, coracoid and clavicle fractures, and of course shoulder dislocation and leg and wing breaks.
The adrenaline rush from the strike can allow the bird to fly some distance, even with most of these injuries. There, they will succumb to the pain and the injury, and fail to survive due to the inability to forage. Concussion alone causes the inability to thermoregulate (stay warm or cool). Even shock can impair a bird. If a bird hits hard or takes longer than a few minutes to fly off, then the bird needs to be checked and cared for by a rehabber.
Always capture the bird as soon as it hits the window if possible. They will be stunned, capture is successful then. Place bird in a small box on a soft smooth towel. If after 15 minutes they are bouncing off the walls, look at the bird. Check eyes and head for blood or feather loss. If none, release. Any bird that sits longer needs at least a phone consult. Any bird that has hit really hard, or has left an imprint on the window must come in.
It is expected that most birds that fly off after a window strike ultimately succumb to their injuries or fail to forage well enough to survive.
Here's a picture of a fully flighted tanager with a hematoma and concussion. She had to be hand fed for a full week. She would have starved had the finder not brought her in, and caught her when she was in the stunned period. The swelling pushed her eye down into her cheek by day 3 and had to be lanced. She survived. Took a month of care. The severity of her injury took 3 days to develop. First day was just some feather loss. The swelling took days to get to this stage. You would not see this level of injury in a freshly stricken bird. This is why assessment and care saves birds.
We are losing 500 million birds a year to windows. Yet window strikes can be 100% preventable. Please check out the windows page for lots of options. Avoid the single decals.
Native Bird Care's is celebrating its 10th anniversary! Our main focus is song, shore, and waterbirds. We offer specialized care and facilities for these extraordinary birds..