Bird Sudoku Level 213 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 213 Strategy
Expert Level 213 uses a 9x9 board with 32 perch cells, 12 blockers, and 8 habitats. Use the row and column counts first, then test each open diagonal flight line.
Bird Sudoku Level 213 Solution
Bird positions in the solution: R1C7, R2C9, R3C2, R3C3, R4C8, R5C8, R7C9, R8C1, R8C7, R9C4, R9C9.