– When collecting samples from living animals give preference to less invasive tissues like nails/claws, hair, feathers, skin and blood;
– When collecting samples from dead animals give preference for more than one tissue representing different periods of isotopic assimilation: fast tissues (such as blood and liver), slow tissues (like muscles) and inert tissues (hairs, claws and feathers).
– Tissues from decomposing animals must be avoided.
– During the sampling, collect only the tissue of interest separately from other tissues in order to avoid cross contamination.
– The tissues must be individually packed, kept in a freezer, avoiding contact with any kind of conservative, such as alcohol or formaldehyde.
– Ideally, the tissue should be taken from the same area in all animals from the same group (for example, feathers from the birds’ tails, or hair from the mammals’ back).
– It is of great interest that these samples are associated with a date, biometric data, sex, and location of the individuals sampled (assigning codes)