You've posed a great question, Jean-Pierre. I'll give another example that includes a question from a concerned parrot owner to a renowned avian vet, and I'll include that vet's reply.
My example is that Juniper branches appear on many of the lists of woods that are presumed to be toxic for birds (which are floating around the Internet). I have personally checked with various avian vets about the safety of Juniper branches for use as parrot perches. Those vets have always replied that Juniper branches are safe as long as the shrubs they were removed from were not previously sprayed with chemicals/pesticides. They further advised that it's the Juniper foliage and berries that are toxic, and not the wood.
Here's what Dr. Brian Speer had to say in a reply to someone with the same question (note that he makes a similar point to yours, Jean-Pierre)...
The question as posed to Dr. Speer:
Dr. Speer's reply:My Question: Is Juniper wood toxic to parrots? I read in Gallerstein’s book that only the needles, berries, and stems were toxic.
Dr. Speer, I wrote asking about the Juniper tree and its toxicity to parrots. Below are science articles regarding the Juniper and native birds that rely on the Juniper. If it is not toxic to so many native birds, why do so many sites state that it is toxic to parrots?
http://www.pwrc.usgs.gov/pif/pubs/PJ...%20low-res.pdf
http://bna.birds.cornell.edu/bna/species/485b
http://ir.library.oregonstate.edu/ds...ndle/1957/8971
http://elibrary.unm.edu/sora/wb/v15n02/p0085-p0090.pdf
http://mojavedesert.net/plants/shrubs/juniper.html
http://newmexicobirds.blogspot.com/2...solitaire.html
Above material excerpted from: https://www.parrots.org/ask-an-exper...oning-questionYou have done a good job, taking the time to challenge some of those simple statements. Why do these types of comments about toxic risk to parrots exist out there? In part, by taking known fact from some species and correlating it to others where it is not known to be a problem or even where there is no problem; in part “just to be safe”, and part simple error. This is one of the inherent risks of taking some pieces of information, without verification - sometimes, we end up really out and removed from reality. The catch here: We do not know what parrot species will do that are non-native to areas where Juniper grows, or if there could be a problem in those species..
Here is an excerpt from a summary discussion about Juniper poisoning:
Juniper, Juniperus sp: There are many species used commonly for landscaping. They are all shapes, sizes and colors and are widely distributed throughout North America. The fleshy seed cones are used as a food source for birds, rodents, deer and humans. Some of the toxic principles are diterpene acids, believed to be responsible for abortions in cattle and sheep; terpine-4-ol, responsible for diuretic effects; and sabinyl acetate which causes fetal malformations that are well documented in rats. The other clinical signs after large amounts of Juniperus are eaten include premature births, stillborns, small or weak newborns in cattle and sheep with the dam also being ill. It is not recommended that pregnant animals have access to these shrubs.
The toxic principle seems to be oriented towards abortions or fetal malformations - an issue that kind of seems to be centered about placental mammals - not birds who do not do that pregnancy thing.
The answers to questions about potential toxicity of certain plants and trees for particular animal species are simply unknown. It therefore at times becomes assumed that if an item has been proven toxic for one species it may well be toxic for another. Information of this sort can easily find itself posted around the Internet as factual - when that factual status may ultimately turn out to be false. Arguably, though, I think it's best to err on the side of caution when it comes to the health and safety of our beloved feathered ones.
He wanted to live. He was my Heaven... He's gone!
Thanks Tony, that is a great reply about how misleading information can sometimes be. Common sense rules.
"A busy beak is a happy beak" - David Strom
PlaxMacaws (04-09-2016)