Posted by Deb White on 10/1/2020 to Materials Safety
Leather undoubtedly adds an interesting dimension and great texture to bird toys. My African greys especially love untying leather knots and gnawing on the leather straps. Toy-makers like using leather as it is often easier to work with and safer than many other types of cordage that can ensnare bird toes. But, is all leather safe?
I’ve been asked by bird owners if it is OK to re-purpose leather belts, shoes, shoelaces and bags into bird toys. The answer to that question is highly dependent on how the leather was processed (tanned) by the manufacturer.
Tanning is the process of converting animal skins and hides into leather. Animal skin is comprised of a structural protein called collagen. The tanning process stabilizes these proteins so they will not naturally decompose.
Most of the tanning methods employed today use toxic chemicals such as chromium sulfate and formaldehyde. Due to the use of heavy metals, the leather produced by these means are not bird-safe!
Vegetable tanning is the only acceptable process that results in leather safe for use in bird toys. This method dates to approximately 6000 BCE and, as the name suggests, veg-tanning is an organic method that utilizes natural vegetable tannins from bark or other plant tissues. Tannins from trees such as oak, chestnut, or mimosa are popular, but hundreds of tree types and other plants are known to have been used.
Vegetable tanning is a much longer (months) and therefore more expensive process than chemical tanning (hours). For this reason, over 80% of the leather produced today is chrome tanned and few tanneries still have the capability to produce vegetable-tanned leather.
Are there ways to tell the difference between chromium and vegetable tanned leather?
There are a few clues to look for:
Vegetable tanned leather
Chrome tanned leather
Consistent light brown or tan
Often bands of color due to quick processing time
Absorbs water when wet
Water beads on surface
Turns black when burnt, doesn’t stay lit
Turns bluish-green when lit due to presence of chromium salts, often continues to burn
These “tests” aren’t entirely foolproof so I would caution DIY toy-makers that it is better to be safe than sorry when considering re-purposing leather items from home.
Rest assured that the leather used in Super Bird Creations toys and sold on MakeYourOwnBirdToys.com is vegetable tanned and safe for your birds!