Please define a 'rookery'?

Today was a rare opportunitiy for the public to be admitted to the grounds at Fort Leavenworth in order to view the "Rookery." It's the oldest house in Kansas, and the reason it is called the "Rookery" are lost in time. It has been home to many Army officers, including Douglas McArthur.





There was also, in old Chicago, a building called the "Rookery," which was the meeting place of many of Chicago's industrialists of the late 1800's.





Does the word have something to do with where large numbers of birds nest, or am I totally confused?|||The only way I have ever heard "rookery" used is as a nesting place for many birds.


I do not know why it is used to refer to a building.