There's also a useful visual identification guide to the country's most common trees, by bark, leaves or seeds.

Visual identification, even in the hand, may be impossible for poorly marked birds.

However, the challenges are daunting, considering that most mailrooms are using one-piece-at-a-time visual identification and manual sorting methods.

The borders of these amelanotic melanomas are often indistinct, making visual identification without a dermatoscope very difficult.

Along the top of the fiche a title may be recorded for visual identification.