A banned pesticide killed two buzzards found next to a rabbit bait in a field near Boat of Garten, police have said.
Northern Constabulary and Strathspey Estate have appealed for help in tracing those responsible for the birds' deaths.
An examination of the buzzards detected cabofuran.
Strathspey Estate staff found the birds in a field next to the A95 road on 15 October. The estate said it was shocked by the poisoning.
A spokesman added: "Considering the efforts made to enhance the wildlife conservation and biodiversity on the estate, it is inconceivable that any of our staff had any part whatsoever in the laying of poisoned bait responsible for the deaths of two buzzards near Boat of Garten.
"Everyone employed by the estate deplores all forms of wildlife crime, and we are working closely with Northern Constabulary to find who is responsible."