"And the Holy Spirit descended on Him in bodily form like a dove.  And a voice came from heaven: "You are my Son, whom I love; with You I am well pleased"-Luke 3:22 (NIV).  
The Bible references birds 300 times and identifies 28-29 different species.  Do you know the first bird mentioned in the Bible?  Noah released a raven to determine if the flood waters were receding.  The most often used...the eagle; the most well known...the rooster.  The dove, however, was the Holy Spirit's chosen form when He descended upon Christ Jesus and is mentioned in all four of Gospels (Matthew 3:16; Mark 1:10; Luke 3:22; John 1:32).  An appropriate choice...doves were the required sacrifice for guilt and purification.  God sent down "His pure Sweet Love," on our atoning Sacrifice..."a sign from above"..."on the wings of a Dove."