Maeve,
A variation on Richard Harlow's "feeder":  take a piece of wood  
(about 11" x 4" x 2") and put two large nails through it, long enough  
and spaced to fit two orange halves.  Screw in an eyelet screw on top  
on each end, attach a string or wire loop and hang it from a tree  
branch.  No critters have found it and the orioles find it in minutes  
of hanging!  They'll eat through a pair of halves every day for  
days.  Happy carpentering.
Janet Watton
Randolph Center