"As a club, we are very disappointed to lose the services of Greg for an extended period of time."
Bird's lawyer, Jim Hall, unsuccessfully argued that Australian back-rower Corey Parker held the greater responsibility for Nightingale ending up in a dangerous position.
"There was low force from player Bird [but] the force from player Parker was high or moderate," Hall said.
"The three players [the other was Australian winger Alex Johnston] played a part in the tackle going wrong.
"Player Parker took control of the tackle and pulled the player down."
Bird had pleaded guilty to a dangerous throw but had sought a downgrade from a grade one to a grade two.
However, judiciary prosecutor Peter McGrath successfully argued that "the danger or the potential of danger is what makes the grading appropriate... There is nothing trivial about it."
Through numerous angles of the tackle, McGrath said, Bird had "re-gripped" or made a "second effort" in tackling Nightingale and then lifting the St George Illawarra star into a dangerous position.
McGrath said that neither Parker nor Johnston had contributed to the position Nightingale was placed in.
"Player Parker really lessens the force or impetus," McGrath said.
In giving evidence, Bird conceded it was "an awkward tackle" but said: "I'm suggesting it wasn't a lifting movement, I wasn't in control."
Trent Merrin shapes as the most likely replacement for Bird in NSW's back row, with Boyd Cordner, Ryan James and Josh Jackson among the other possibilities.
Most suspended players since the NRL was formed in 1998*
John Hopoate 45 weeks
Luke O'Donnell/Craig Smith 32 weeks
Greg Bird 29 weeks
Danny Williams 28 weeks
Jason Stevens/Adrian Morley 26 weeks
* Source: Fox Sports Stats
Greg BIrd's suspensions since his NRL debut in 2002
2004: Striking - 10 matches
2004: Dangerous throw - 3 matches
2005: Dangerous throw - 2 matches
2011: Striking - 1 match
2014: Dangerous throw - 2 matches
2014: Dangerous throw - 2 matches
2014: Dangerous throw - 1 match
2015: Dangerous throw - 8 matches
*No bans resulted for Bird after judiciary appearances in 2003 and 2013.
** Source: Fox Sports Stats
- AAP