Why are some tags on the right wing and others on the left?

Condors can be tagged on either wing. In the early days of the California Condor Recovery Program, every condor was tagged on both wings. Now condors in southern California just wear one wing tag and it can be on either side. The tags are attached by piercing the patagium of the wing. When wearing transmitters this piercing holes can enlarge overtime. We closely monitor the size of these holes when condors are trapped and handled and alternate wings to allow large holes to shrink back down so they can continue to be used.