Maybe you already know this, but in case..
If you go to the main page, choose "Accomondation/Top Choise", scroll down until you see Birdie´s Nest, click on "Details".
Now you see the page for Birdie´s Nest, choose "Map", and a satelite picture over the Black Rock area will come up and if you adjust the map using "-", you will have a better over all view over where Birdie´s Nest is situated and you will also see the manin road. Using "Hybrid" will give you a better view as the roads will come up in a better way.
By making the map smaller and using the arrow "down" you will very clear see the main road from the Airport via Bon Accord and Cannaan up to the junction where Shirvan Rd meets Claude Noel Hwy. You turn left on Shirvan Rd passing Bucco, crossing Bucco Bay Road, passing Mt Irvine Golf Lane, and further on Mt Irvine Bay, and after the hills you reach the village Black Rock.
If you buy a roap map at the airport, than I´m sure you will have no problems to find your way to Birdie´s nest.