Colour the sugarpaste the day before, making a pale pistachio green with the 3 food colour pastes.
To cover the cake with sugarpaste, remove any star anise flowers from the top and turn it upside down on a clean work surface, so the flat base is uppermost. Warm the jam gently in a small pan, then push it through a sieve and brush it all over the cake.
Dust a clean work surface and a rolling pin with icing sugar and roll out the sugarpaste into a circle slightly larger than the diameter of the cake and sides and no thinner than 5mm. Keep moving the sugarpaste and run a palette knife underneath it or dust with more icing sugar as necessary, as it is so frustrating if it sticks to the work surface.
Lift the sugarpaste on to the cake with your hands (or wrap it loosely around the rolling pin) and place it on the cake. Rub all over and smooth around the sides until you have a good shape, then cut away the excess sugarpaste. Run a palette knife under the cake and lift it on to the final plate, board or cake stand. Leave the icing to set for an hour or 2, if possible. It can be decorated straight away, but be careful not to dent the icing.
Using the royal icing, attach the branch to the top of the cake, and secure the 3 ribbons with a dab of royal icing at the back. Push the bird in among the flowers.