Birdstone

(from the article `Equestrian Sports`) Belmont Stakes winner Birdstone was retired in November when he was diagnosed with a bone chip in his left front ankle. He won five of nine starts ...
Found on http://www.britannica.com/eb/a-z/b/68

Birdstone

Typically a stone artifact, thought to be an Atlatl weight which was shaped like a bird. Quite possibly some other type of cerimonial object. Some birdstones have buldging or 'Pop' eyes. Usually made from a banded slate.
Found on http://www.encyclo.co.uk/visitor-contributions.php

Birdstone

Owned and bred by Marylou Whitney of Whitney family racing fame, Birdstone won the Champagne Stakes, a leading race for two-year-olds, at Belmont Park in 2003, but was not a factor in the first two Triple Crown races (finishing eighth in the Kentucky Derby and skipping the Preakness Stakes) and was a 36-1 longshot when he upset the overwhelmingly
Found on http://en.wikipedia.org/wiki/Birdstone
No exact match found