The ornamental design for the insect trap with bird guards, as shown.
FIG. 1 is a perspective view of an insect trap with bird guards in accordance with the present design;
FIG. 2 is a front view of the insect trap with bird guards shown in FIG. 1, which due to symmetry is the same as the back view of the insect trap with bird guards;
FIG. 3 is a left side view of the insect trap with bird guards shown in FIG. 1, which due to symmetry is the same as the right side view of the insect trap with bird guards;
FIG. 4 is a top view of the insect trap with bird guards shown in FIG. 1, which due to symmetry is the same as the bottom view of the insect trap with bird guards.