Can a fireplace fumes kill a cockatiel?

It really depends on how close to the fireplace you have your cockatiel. SMOKE KILLS. Even YOU can die because of smoke inhalation. Sadly, having a cockatiel in the same room as a fireplace is not going to kill it, I tried that in the past to get mine to be quiet. However if you have them within a small area around the fireplace where the fumes are the most intense, Yes, it CAN and Will kill the bird.... so, if you are looking for a way to terminate your bird, sit the cage on the mantle, and build a very smoky fire. The bird will just go to sleep, and never awake again....