Bird Sudoku Level 239 Hint
Look for perches that share long open diagonals. If no blocker sits between two possible birds, those placements cannot both be used.
Bird Sudoku Level 239 Strategy
Master Level 239 uses a 10x10 board with 47 perch cells, 13 blockers, and 11 habitats. Use the row and column counts first, then test each open diagonal flight line.
Bird Sudoku Level 239 Solution
Bird positions in the solution: R1C1, R3C5, R3C7, R4C5, R4C10, R5C2, R6C6, R6C9, R7C1, R7C6, R8C8, R9C2, R9C5, R10C2, R10C5.