Use Hong Kong Post, i.e. the post office. They will sell you the box, etc. If you don’t need it in a hurry, send it by surface mail. That is quite cheap. Otherwise I would suggest “Speed Post” which is quite fast, although can be a bit pricey. See http://www.hongkongpost.hk/ for cost. The item is automatically insured if you send it by Speed Post for something close to US$100, which should more than cover the cost of the bird cage.

You will find all staff speak English.

There are post offices in many locations, IMO the best one for you is the main post office near the Star Ferry Pier in Central. It is open more hours (and on Sundays) and has shorter lines (usually). There is a separate shop on the ground floor to buy boxes and wrapping materials. The post office has tape you can use, you don’t have to buy tape. You can take the Star Ferry over after the bird market and go right to the Post Office

See the website for all the locations.

Fed Ex or UPS will be quite a bit more expensive.

I am not aware of any restricitons in shipping a birdcage from Hong Kong. I don't thing that there is a US restriction on receiving the cage. But you would need to check with US Customs on that.

Sorry, the location I am recommending is the General Post Office, 2 Connaught Place. This is near the IFC Mall and the Star Ferry.

From the Star Ferry exit in Central, take the pedestrian overpass away from the water for about 500 meters over construction until you get to some buildings, the General Post Office is the first entrance on the left. There should be signs. You will enter on the first floor, you need to go downstairs to the ground floor to buy boxes and mail packages.

From the bird market it would probably be faster (although not nearly as scenic) to take the MTR to the Central station, exit Door A. When facing busy Connaught Road (the one with the street tram) turn right, go to the corner with the light, turn left and cross Connaught Road here, go up the stairway about 10 yards ahead on your right to the pedestiran overpass. Once at the top of the stairs, turn right, then left at the inersection about 10 feet further. From here follow signs (above your head) about 100 meters to the entrance to the General Post Office on the right.

i carried our birdcage home as hand luggage

Thanks for responses! That was very helpful!

Sorry, I was at the GPO today and now realize I gave directions from the MTR to the post office via Exit Door C. You really want to use Exit Door A, which is faster.

For Exit Door A: you will come up escalators at Exit Door A to the street level. Turn right and face the busy street here, step out to the street and look right. You will see a pair of escalators with a set of steps in the middle. Go up either stairs or escalator to the pedestrian overpass. At the top, ignore the walkway immediately to your left and proceed straight. This walkway will dead-end in about 20 feet, go left here. You may notice signs overhead which say “General Post Office”. Walk straight ahead, from here it is about 200 meters to the GPO. The first building on the right will be Jardine House, keep walking straight on the overpass. Ignore the flight of stairs on the right going down to the street, you may notice the white General Post Office Building off to the right just past the stairs. The next right off the walkway is the General Post Office, this will take you directly into the building on the first (upper) floor. Turn right, go into the building, walk straight ahead and look for the escalator going down. The counters for mailing packages is on the ground floor behind the escalators, the small shop selling boxes is at the far end of the open hall where these counters are located.

Not to nitpick, but getting off the Tsuen Wan Line heading to the GPO, the exit to take is K. Make a U-turn after coming up to Statue Square, cross Chater Rd, then go through the pedestrian tunnel and you're right there. No steps, no extra escalators to ride, and less crowded then the Exit A area. Just one street to cross at a stoplight.

Its a looooooong walk underground to Door K....