Vultures were among the unclean animals for the Israelites (Leviticus 11:13, 18; Deuteronomy 14:12, 17). This means that Israelites were not permitted to eat vultures. In some of the references both eagles and vultures are mentioned.
Vulture at the Hai-Bar Reserve in Israel. Photo by Ferrell Jenkins.
In the Greek New Testament the word aetos is translated both eagle (Revelation 8:13; 12:14) and vulture (Matthew 24:28; Luke 17:37).
One of the most memorable comments about the vulture was made by Jesus in His discussion of the destruction of Jerusalem. He described the condition of the Jewish state at the time when the Roman armies invaded the country.
Wherever the corpse is, there the vultures will gather. (Matthew 24:28 ESV)
Not a pretty picture. And a clear warning for all.
Ferrell's Travel Blog 
Now, the Christ prophesied for the past, the present and the future, and good St Peter confirmed that all things were clean!
Bald heads can get in and out of body cavities easier and, more importantly, can be cleaned easier. Also, if they are feeding and face a sudden threat they will vomit up whatever they have eaten to make themselves light enough to lift off. Truly a good candidate for “unclean”. Also, eagles are not above scavenging the dead so there is good reason for them to show up as unclean in Scripture.
I’ve just been reading Leviticus. Quite an ugly bird – I heard they have no feathers on their head so they can get at the stuff they eat better.