I've decided to get a harness for one of my caiques and have been researching the different types available. Having discovered some information, I thought I would share with you as well!
The second most popular harness available, the Feather Tether comes in many colors and sizes. The Feather Tether comes in one piece, but you are required to snap pieces together once on the bird. The disadvantages to this model include:
The harness surrounds the birds crop which can be unsafe
The D-clip used on the harness is a bit heavy and sits on the birds chest where he can easily access it to chew
Bird owners that have purchased the harness talk about it with mixed results. Some say that their bird uses it with no trouble, while others say their birds are afraid of it and they have not been able to use it successfully.
The Aviator Harness
This harness is by far one of the most talked about harness. Manufactured by Steve Hartman, who strongly believes in free flight, this harness was made to accomodate free flighted parrots. The harness is one piece making it easy to put on your bird. Along with the harness comes an instructional DVD, teaching how to properly acclimate your parrot to the harness and how to safely put the harness on. A suprising amount of owners report that they have tried previous versions of harnesses, particularly the Feather Tether, and having had no luck with them found the Aviator readily accepted by their bird. The Aviator harness does not use a snap clip with leash, like the Feather Tether, Bird Diaper, and Ortho Bird Harnesses do. Instead the leash consists of bungeed material so that if a bird were to fall or fly they would not get pulled back and hurt. Another positive note about this harness is that it is not made to sit around the birds crop like other brands are. This is much safer for the bird.
Unlike other smiliar products, this is actually not a harness at all. The Bird Diaper is made to keep your shoulder clean and your bird safe. Bird Diapers come in many different colors and sizes. Most bird owners report more trouble using the Bird Diaper because it is more restrictive then a harness, and some birds do not do well with it. Owners who have Bird Diapers with birds that will accept them say they enjoy Bird Diapers and feel the Diapers are not too restrictive on their birds, but do not use the Diapers for an extended length of time.
Ortho Bird Harness
Harness made by Ortho Bird. This harness resembles another popular harness, the Feather Tether. One noted flaw in the design is that the Ortho Bird harness sits around the birds crop. It appears to have multiple clips, which could pose a problem when trying to put the harness on the bird. Little information is available about the harness, other then from suppliers. The manufacturer's website is down, so no additional information is currently available. Unfortunately I could not tell much about this harness from the photo provided by suppliers, and could find no one that currently uses this harness.
Kaylor Bird Harness
Only available at fredbird.com. Harness comes with woven tie rather then easy disconect clip. Said to have been available for around 15 years. Other than information on the fredbird website, little information was available about this harness. One interesting thing that I was reading in regards to the Kaylor Collar, as it is called, is that the manufacturers of the harness claim it can be left on for days without harming the bird or the birds feathers. I would not personally recommend anyone leaving a harness on their bird for any extended length of time, as there is always danger that the harness could get caught up in something, or rub and irritate skin and feathers. I could tell little about this harness from photos, and found no one currently using this model to interview.
When doing research on these harnesses, I discovered most claimed their harness had been made in conjuction with an avian veterinarian. Unfortunately no information about the vet was available so I was unable to interview the vet to find out more.
All of the above harnesses share two things in common: they are made out of sturdy, brightly colored nylon, and they may not accomodate small birds. The Feather Tether does not fit birds under 100 grams, as does the Ortho Bird Harness. The Kaylor Collar says it fits a bird as small as a cockatiel, but does not give a weight chart to go by. The Aviator Harness accomodates birds from 75 grams and up. Bird Diapers say they accomodate birds ranging from petite to colassal, but I was unable to find a weight chart to compare.
After doing this research, I have decided on an Aviator Harness for my caique. Previously we have tried a Feather Tether and my bird was deathly afraid of it. We got to the point where it could be put on, but he can easily slip out of it, even after I exchanged it for a smaller size. Seeing as how the Aviator compares to others in safety and quality it will be my choice for another harness attempt.