Cruelty--that's for sure, at least by our contemporary standards. Apparently the falcon's eyesight is so keen that it inhibits the establishing of a close relationship between the bird and its trainer. Here's a site that has more details:
http://www.arab-heritage.com/falconry.htm

An interesting bit of info I found while checking this out: the leather hood now used on the falcon is called a burgah, which is another form of burqa. Talk about being covered.