The ornamental design for a beavertailheadband, as shown and described.
FIG. 1 is a front perspective view of a beaver tail headband in accordance with the present invention;
FIG. 2 is a rear perspective view of a beaver tail headband in accordance with the present invention;
FIG. 3 is a side perspective view of a beaver tail headband in accordance with the present invention, the opposite side perspective view being a mirror image thereof;
FIG. 4 is a top perspective view of a beaver tail headband in accordance with the present invention; and,
FIG. 5 is a bottom perspective view of a beaver tail headbande in accordance with the present invention.