Hello Robin. I'm so sorry for your loss. It is not possible for me to give you an exact cause of death. Only a necropsy by a well qualified Avian vet might do that. What I can do is try to give you enough information for you to do your own detective work to see if you can arrive at any possible causes, using the information at the links I'm going to give you. While 16 years is an above average life span for a Tiel in captivity, it's not really considered old age. So much of their life span is determined by proper diet and by observing all safety issues, especially as respects toxic products that we should never use around them. The fact that you had a mite protector on her cage is cause for concern and definitely cannot be ruled out as a contributing factor. I would like to see the day when those are outlawed and when money hungry pet stores took them and pretty much all the rest of their over the counter junk off the market. However, so long as the unsuspecting public is buying them, they will continue to be available with no regard whatsoever to bird safety and pet store employees will continue to tell people they have a "witches brew" that will cure everything. In the first place, an indoor bird is almost never, ever, going to get mites. Even if they did, that is not the answer. Keeping a bird confined, close to one of those is like shutting yourself up in a small area with mothballs or insecticides. The damage is to their respiratory systems, it's cumulative and does kill, over time. There are many other products in our homes we must make sure we never expose our birds to and those lists should help you with that. Obviously diet plays a big part in how long our birds may live. If she has been on a seed only, or seed mostly diet all her life she would have been at risk of fatty liver disease, (Hepatic Lipisosis), fatty tumors and other obesity issues. Birds should only have about 30% seeds and seed products in their diet. The rest should be pellets, fruits, veggies, leafy greens and much more. Unless we are aware of what to look for, detecting a problem quickly and acting immediately can be difficult. One of the problems we have with our parrots is their very strong instinct to mask all symptoms of illness or injury, from us. In the wild, they are prey and to show weakness is to get kicked out of the safety of the flock. By the time we see any symptoms, it's because they are too sick and too weak to keep up the pretense. A couple of the first things we will be able to notice is a change in behavior, (less playing, less or no talking, etc.), any change in the appearance of the droppings that lasts more than 24 hours and cannot be accounted for by diet. For example, a lot of fruits or veggies one day can make more runny droppings but it should not last more than a day, then go back to normal. Other symptoms are sitting with feathers fluffed, giving up the perches and staying on the cage floor, and sleeping an inordinate amount of time. If she had exhibited even one of these symptoms, it would have been a heads up to get her to an Avian vet right away. If you know for sure you had a female bird, egg binding can not be ruled out. Again, that is usually caused by improper diet and for sure, by a lack of calcium in her diet. She should have had a never ending source of cuttlebone, plus the rest of a good balanced diet. Egg binding is life threatening and if not recognized and dealt with immediately, 99 out of 100 times, the bird is lost. These links I'm going to give you are the same ones I give to all prospective owners and all novice owners to hopefully help them prepare for the arrivial of a new bird and to keep it safe and healthy. I hope they may help you to pin down a possible cause and in turn, may help you to at least get closure. Hopefully it will also be helpful to you, should you decide to get another bird at some point. What we know about keeping our birds safe is constantly changing so it puts a burden on us to try to stay up to date with recent discoveries. What we thought was the gospel in bird care today, may change tomorrow. Look over all this information and if you have any more questions at all, just let me know. I know what a very sad and unsettling time this is for you and if I can offer any further help, I'll be glad to. Patricia
Click here: BirdsnWays - Articles & FAQs on pet birds, pet parrots & exotic bird species - Cockatiels
Life After Weaning - Your Companion Bird and You
Caring For Your Pet Cockatiel
Fatty Liver Disease in Cockatiels
Click here: Cockatiels as Pets - Choosing a Cockatiel, Cages and Feeding
Click here: More Birds Die as a Result of Air Fresheners: That Stinks!!
Click here: Alerts Dangers and Toxins for Pet Birds Parrots
Click here: Bird; Birds: Safe, Toxic Trees, Woods. Safe Tree Wood. Poisonous. Parrots.
Click here: Toxic and Safe Plants/Trees for Birds - Household Poisons
Click here: Birdsnways - Safe Plants & Trees for pet birds, pet parrots &exotic birds
Toronto Humane Society :: Common Poisonous Plants
Click here: Bird Proofing Your Home: Household Hazards for Birds
Click here: Bird Proofing Your Home - Avoid These Pet Bird Hazards
Parrot C&onsultant
Published author, free lance bird behaviorist, adviser to the parrots at Sarasota Jungle Gardens.