Citizen science: reporting sightings and tracks usefully

Where does a species occur? Is it becoming more common or rarer? When do migratory birds return? Questions like these can only be answered when a very large number of observations from many places and over many years come together – far more than experts alone could record. That is where volunteers come in.

For data from many hands to be usable, it must be comparable. That is why good projects have a fixed protocol: they define how long you count, along which route, what exactly is recorded and how the certainty of an identification is stated. Anyone who sticks to the protocol supplies data that can be combined with everyone else's.

One point surprises many people: in structured counts, “nothing found” is valuable information too. If someone walks the same route every year and suddenly stops seeing a species, that is exactly the important news. Anyone who reports only rarities distorts the picture.

A good record contains four things: what did you observe? When exactly (date and time)? Where exactly? And how sure are you? A smartphone often records place and time automatically; but check that the details are right, especially if you enter the record later.

Evidence makes your record verifiable: a photo with a scale, a sound recording for bird calls, measurements for tracks. Experts who check records can use them to spot mistakes and confirm or correct uncertain identifications.

Honesty matters more than completeness. Report only what you can identify with confidence, or explicitly mark it as “uncertain” or only at a broader level, for example “a mustelid” instead of a specific species. When reviewers ask questions or change an identification, that is not a reproach but part of quality control.

No record photo is worth disturbing an animal. Do not go to nests, dens or eyries to make a record, and keep your distance. Binoculars or a telephoto lens replace closeness.

The exact locations of rare or disturbance-sensitive species – such as breeding sites, dens or eyries – do not belong publicly online with coordinates. They could attract people who disturb or harm the animals. Many platforms obscure such data automatically; check the settings.

Pay attention to people too: before uploading, remove photos and camera-trap images in which people or number plates can be recognised, or blur them. And with roadkill, only take photos if this is possible without danger from traffic; do not take the animals.

Citizen science comes in many forms. In counts, people count all the birds in their garden for an hour on a set date. On tracking transects, you walk a fixed route after snowfall and record all the tracks that cross it. In camera-trap projects, camera images are analysed together. And roadkill records show where animals are run over particularly often – valuable clues for crossing structures.

Many countries have regional recording and mapping projects for mammals, birds, amphibians and other groups. Choose a project with a clear question and understandable instructions. This knowledge base deliberately recommends no individual platforms; ask conservation organisations, museums or authorities in your region.

In 2015 the European Citizen Science Association formulated ten principles for good citizen science. They include genuinely involving volunteers, projects having scientific value, data being as openly accessible as possible and legal and ethical issues being taken into account.

Taking part is also worthwhile for you: you learn to look more closely, recognise species better and deal honestly with uncertainty. For school classes and clubs, a joint project is a great experience that supports real research.