Both notes in "Behind the scenes" causes his name to be Kirley Duke (née McCormack). --Danniesen 30 July 2010 14:38

Well, his mother might have married twice and have Kirkley from the first marriage and his sister from the second. --  Seth Cooper  owl post! 12:38, July 30, 2010 (UTC)

It´s still speculation. It is also possible that his mum changed her surname after giving birth to her first child, making his mother Mrs McCormack neé Duke.--Rodolphus 12:43, July 30, 2010 (UTC)

Then her husband is named McCormack --Danniesen 31 July 2010 10:40

In Quidditch Through the Ages, Kirley's sister is referred to only as "Meaghan," not "Meaghan McCormack:" "Her daughter Meaghan currently plays Keeper for the team. (Her son Kirley is lead guitarist with the popular wizarding band The Weird Sisters)."
Now, typically, this type of wording isn't an issue. "Lucius Malfoy and his son Draco..." is just a concise way of saying Draco's last name is also Malfoy. If it was different, the author would probably go to the trouble of pointing it out, as in "Lucius Malfoy and his son Draco Black-Malfoy...".
But, since Kirley's Chocolate Frog card gives his surname as "Duke," we can't just safely assume that the omission of Meaghan's surname in QTTA is intended to imply her surname is McCormack — she could be Meaghan Duke for all we know. Or Meaghan Abbott, Meaghan Montague, etc.
There are plenty of explanations for the mother-son surname discrepancy: Catriona keeping her maiden name when she marries, Catriona divorcing her husband after having two children with him and then remarrying/reverting to her maiden name, etc.
The point is that we can't say what Meaghan's last name is, or why Kirley's last name differs from his mother's, without more information. Starstuff (Owl me!) 22:03, July 31, 2010 (UTC)

You also forgot one other fact; Duke could be his middle name -- i.e. Kirley Duke McCormack and he uses Duke for the band as it flows better. --HarryPotterRules1 (talk) 07:40, August 18, 2016 (UTC)

1971 the only evidence for his birth year that Jonny Greenwood was born in 1971? If it is, that's not exactly a reliable way to determine the age of the character, for many reasons, particularly that this is just a portrayal, not the real Kirley Duke. In addition, if you were going to insist that Kirley must be the same age as Jonny Greenwood, then you'd have to take into account the fact that while the movie was released in 2005, it was set in 1994-1995. Just saying. Slytherclaw5450 (talk) 18:48, July 14, 2014 (UTC)

No. The wizard cards in the videio games show the birthdates of all band members.--Rodolphus (talk) 18:51, July 14, 2014 (UTC)

Okay, thank you. Slytherclaw5450 (talk) 18:53, July 14, 2014 (UTC)