The Collaborative International Dictionary of English v.0.48:

Rookery \Rook"er*y\, n.; pl. Rookeries.
   1. The breeding place of a colony of rooks; also, the birds
      themselves. --Tennyson.
      [1913 Webster]

   2. A breeding place of other gregarious birds, as of herons,
      penguins, etc.
      [1913 Webster]

   3. The breeding ground of seals, esp. of the fur seals.
      [1913 Webster]

   4. A dilapidated building with many rooms and occupants; a
      cluster of dilapidated or mean buildings.
      [1913 Webster]

   5. A brothel. [Low]
      [1913 Webster]

WordNet (r) 3.0 (2006):

rookery
    n 1: a breeding ground for gregarious birds (such as rooks)

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "rookery":
   Augean stables, birthplace, breeding place, brooder, cradle, dump,
   forcing bed, hatchery, hole, hotbed, hovel, incubator, nest, nidus,
   nursery, pesthole, pigpen, pigsty, plague spot, slum, stable, sty,
   tenement, the slums, warren