The following article is used with the written permission of the author, Gillian Willis, pharmacist and toxicologist.
Red maple (Acer rubrum) is also known as maple, soft maple, scarlet maple, curled maple and swamp maple.Maple Trees
Maple bark itself, is probably not toxic. However, there is a fungus that can grow on the bark, inhalation of which, can cause maple bark disease ( a form of allergic alveolitis). Maple wood would be safe to use for natural wood perches once the bark has been removed.
Maple seeds and the sugar-rich young leaves are considered edible EXCEPT to horses.
Wilted and dry, not FRESH, maple leaves produce an oxidant which has caused hemolytic anemia, renal failure, pulmonary edema and death in horses.