There were four other people living in the same apartment building as her, all of whom were avid birdwatchers like Bonnie. One of them must have done it. Look at the clues below. If you know everybody's name, apartment number (#1 through #4), and favourite bird, you will know who is guilty.
1. The guilty person's apartment number is not numbered one higher or one lower than Hal's.
2. Joe's favourite bird is the crow; his apartment number is one lower than that of Ike (who doesn't like robins).
3. The guilty person's apartment is not #3 (the number of the finch-lover's).
4. Gil is neither at apartment #1 nor the wren-lover.