In many apartments, you can hear it if a dog whines, child cries or if someone is watching tv, footsteps over-head, loose change falling, keys tossed to the floor, upstairs neighbors box-spring when laying down on a bed, vacuums, phones ringing, conversations etc...I am not that familiar with bourkes specifically.
I just know that all of the standard parakeets I have ever known would have stressed me out in a traditional, multi-level apartment setting because their constant chirping/chattering and occasional screeching would have been heard by many--even though it isn't cockatoo-scream loud. I also had a real issue with smells entering my units (I even tried taping around pipes etc).
Most of my apartments in the US have not been very sound-proof (then again, none were built prior to the 1950s). I slept with silicone earplugs every night and still could hear certain late-night activities with them in.
My neighbor used to work-out with some sort of rowing machine and the repetitive scraping sound drove me insane...I never did anything about it, but it was super annoying.
I could tell you about my old neighbors bathroom habits, love-lives (ew), illness (coughing etc), family troubles, pets, musical-taste etc...and I lived in a pretty decent complex by US standards...Unless you are living in a turn-of-the-century solid brick box with very thick walls and floors, the walls will likely be fairly thin...Something like frequent chirping could easily become bothersome to a non-consenting neighbor.
I had a pair of wild doves that lived outside of my unit in a tree or maybe on the roof, and even though their cooing was quiet, I could hear it clearly ALL DAY and at like 3am (it would only ever stop for like 5 minutes and then start back up)-- I was ready to lose my mind because of the repetition...I never thought of them as being obnoxious because in small doses, the sound is pleasant...but my goodness....not all day everyday.
I didn't mean that it couldn't be done (a bird in an apartment) but again, it is really going to depend on the bird you get (including species, individual personality, and its level of happiness), your neighbors and other apartment policies (such as noise-complaint rules and often mandatory maintenance requirements, like insecticide in units etc). I just meant to say that if possible noise is going to be a deal-breaker, getting a bird seems like a big risk if moving,eviction or re-homing the bird = only solutions following noise issues. I lived in an apartment with my bird for a bit out of necessity and it was a constant source of anxiety.
In terms of general noise, a duplex situation might be somewhat better---or one of those single-story rows of apartments that are connected but do not require neighbors above or below<--- that was actually the quietest style of apartment housing I have ever lived in because I only shared 1 wall on either side of the apartment and it was an older set of buildings (not old by construction standards, but built in the 50s).
is perhaps the most suitable as long as the number you keep is reasonable - 6 to 8 is a good number. Any thing more will create noise. Anything less will not give them a "flock feeling". You may get lucky with Cockatiels 
too. But Agapornis
lovebirds are a big no because their calls can be ear piercing.
