How Birds Are Selected
There are two different selections in each question:
- The target bird is the species whose recording you hear.
- The other three answer choices are distractors. Their similarity is controlled by the difficulty setting.
Difficulty does not usually change the target pool. The quiz type and, for area-based quizzes, your selected area and season determine which target birds are eligible.
With Expert mode enabled, you choose the target from a searchable list of all birds eligible for the current quiz instead of choosing from four answer buttons.
Quiz types
| Quiz | Birds that can appear |
|---|---|
| General Quiz | Birds in the selected area and season, narrowed by the observation-frequency range. The range is part of difficulty settings. If it leaves too few species, the quiz falls back to all birds matching the area and season. |
| Common Birds | The most frequently observed birds in the selected area and season. Choose a level for the 10, 20, or 30 most common species. |
| My Lists | Birds in the list you selected. Create and manage lists in Search. A list needs at least four birds to be used in a quiz. |
| Learning Mode | Birds in the learning-status group you selected: Review, Learning, or Mastered. Groups with too few birds are not offered as quiz levels. |
| Classification | Birds in a selected scientific group, such as an order, family, or genus, within your area and season. Available groups depend on those settings. |
Area and season filters are used for General, Common Birds, and Classification quizzes. My Lists uses the contents of your list, Learning Mode uses your saved learning status.
How distractors are chosen
The app uses bird classification to find alternatives at the similarity level you selected. For example, closer choices may come from the same family or genus. It tries to use birds from the current quiz's eligible pool, so a question stays consistent with that quiz. If the pool does not contain enough choices at the requested similarity, the app broadens the search to less closely related groups.
With Expert mode off, a multiple-choice question needs four eligible birds. If there are too few, try a broader area, another season or quiz, or a list with more birds.
Learning and repetition
The app uses a Leitner spaced-repetition system in Training: birds you are still learning come back sooner, while birds you identify consistently are shown less often. For more details, see the Leitner system on Wikipedia.
Challenge uses a simple random order and does not use that spaced-repetition queue. Your learning status is still updated from your answers and is visible in My Lists, you can also choose a status as a quiz level in Learning Mode.