Vultures are in grave danger. Of the six species occurring in Namibia, all are listed as Endangered or Critically Endangered. The main threat is poisoning, either deliberate or due to human negligence. Lesser-known threats include habitat loss, lead poisoning – as they ingest bullet fragments from animals that are shot - and collision with or electrocution on powerlines. These birds are, however, critical to the functioning of our natural ecosystems and play an important role in controlling diseases that affect animals and humans. Conservation relies on knowledge of the plants and animals we are trying to save. We especially need to know whether or not the species we are concerned about are doing better or worse than they would be if it weren't for human activities. 'To achieve this, we need what is known as baseline information. Examples of baseline information include: the chance an animal has of surviving each year; the rate at which they usually reproduce; and the average lifespan in the wild. Once we know these figures, we need to monitor them over time for each species of concern so that we can react quickly if things seem to be deteriorating, or we can learn whether or not our efforts are bearing fruit by improving or maintaining these figures. Bird researchers have developed a number of methods to try and obtain these figures for their study species. Individual birds are nearly always impossible to distinguish from others of the same species, hence finding out what happens to a particular bird over the course of its lifetime is a real challenge. Ever since the turn of the 20th century (and since 1948 in southern Africa), people have put simple uniquely numbered metal rings around a bird's leg that function as an "identity document". If a ringed bird is caught again or found dead, the person who finds it can report its ID number to the organisation that ringed it in the first place. While this method is still used today, it has its limitations - birds must either be caught or found dead to record the information on their legs. While some rings have been colour-coded to allow one to see the unique code through binoculars, they are not always that easy to see or obvious enough for the casual observer to realise their significance. These issues have been largely overcome by using plastic tags that are attached to the bird's wing and look like a colourful extra feather. Attaching these tags is not painful for the bird, and tagged subjects seem to barely notice them. Like a ring, each tag functions as a unique ID, but they are much easier to see from a distance than rings. This means that a birder who sees a tagged bird can read the numbers using a pair of field binoculars and report their sighting to the relevant authority. Wing tags thus greatly increase the chance of "citizen scientists" noting and reporting tag numbers, which improves the data researchers get from their study. Because metal rings last longer than plastic wing tags, researchers usually combine these methods. A recent study by a team of international and Namibian scientists on Lappet-faced Vultures put wing tags to good use. This study in the Namib-Naukluft Park is part of a long-term monitoring effort by Vultures Namibia that used metal and colour rings since 1991 and started using wing tags instead of coloured rings in 2006 to mark young vultures in the nest. Thereafter, they asked citizen scientists to report when they saw a tag that they could read or when they recovered a ringed dead bird.