Unsolved Mysteries...

This is a mystery which I have found no solution to. I haven't found any one who has thought about this as a mystery independently. There are absolutely no references of this anywhere on the internet - at least a Google search on this subject completely fails to be informative.

Where did the pigeons in the 168th Street Subway Station in Manhattan come from?

For those of you who are yet to go to this place, 168th Street in Manhattan is well known because of the Columbia Presbyterian Hospital. There are two levels in this subway station - a level for the A, C, E trains and a level for the 1 and 9 trains. The 1, 9 trains come at a depth far greater than the depth of the other level - I want to hint at the fact that this region is quite deep below the ground. The only way humans have access to the platforms is through two huge elevators which are manned by MTA employees. There is also a fire-escape which has stairs, but that goes through a door. The only other outlet to the rest of the world is the tunnel itself, through which the trains come and go. But would a pigeon consider negotiating this tunnel in all its darkness? After all, they are birds, not bats.

There are about 20 pigeons in the station. So, where did the pigeons come from?

Suggested solutions:

• There are air vents on the ceiling of the tunnel through which the pigeons come and go.

  I am not too sure about this. Looking around in the station, there weren't any obvious air vents. If there was a secret air vent, how would the pigeons have found out about it, and how do all of them know it so well? If they came into this chamber by chance, are they trapped?

• The other explanation suggested was that maybe they got trapped inside the chamber when it was being constructed. There is enough food to feed on - i.e insects, mice etc and the life cycle has continued. Which makes me ask - so have these pigeons ever seen daylight?
• Article published in the New York Times on March 5, 2002:
  Waiting for the A Train, the Sophisticated Pigeon

• The only link I could find... A history of 168th street station
• Another resource - thread on the newsgroups. This actually confirms the plausibility of my initial theory that they are a colony of pigeons that have never seen daylight.

I took these pictures under very very poor lighting... Please pardon.

168th Street Station

The Tunnel

The Station - pigeons would not want to come back here...

Can you see the pigeon?