We do not encourage the use of tags from year to year, mainly due to the fact the adhesive has a shelf life of about one year; therefore, using old tags increases the liklihood that the tag will fall off sometime during the monarch's journey. To illustrate this, if you check out our "Off to Mexico" BLOG at
you will see in the Saturday, March 6th entry that we found a monarch that had obviously been tagged at some point - the scales in the discal cell of one hindwing had been removed in a perfect circle the size of our tags.
It is likely that this monarch was tagged by someone using old leftover tags, but that someone will never know that "their" monarch made it to Mexico and we will probably never complete that tag record.
This is why we have new tags manufactured each year.
So, we know that people will continue to use old tags, but our "official" response is
Please, please, do not use old leftover tags
- you can return them to us at the end of the tagging season if you think the urge to use them the next year will be too great for you
I certainly hope you don't feel that your money was wasted on unused tags...it still helps support Monarch Watch's efforts in education, conservation and research. We simply couldn't exist without your support and that of all the other Monarch Watchers out there - thank you for your continued support!