Solar Tags, do you supply them?

We do not supply solar tags, because they generally do not last any longer than ordinary tags. Solar-powered tags are attractive because they seem to offer the prospect of infinite battery life. Because of this they are easy to sell ! However, they have a number of intrinsic limitations, and at Biotrack we have decided not to supply them. The first limitation is the re-chargeable cell, which is charged by the solar panels. This has a finite life, even if the solar panels do not. Furthermore, rechargeable cells have inherently low energy density, and thus are bulkier than primary cells. The additional circuitry, and the inclusion of a solar panel, makes solar tags less reliable (for example, if the bird dies and is lying on its back, or is hidden in vegetation the solar panels will not work). The solar panel has to be exposed (i.e. not covered by feathers) which potentially increases the drag factor of the tag. In contrast, tags with primary cells are at least partly preened into the plumage.