Count without double-counting
See this course’s project requirements
A citizen-science practice kit with a bounded question, effort log, teaching-key identifications, count audit, cautious comparison, and submission-eligibility checklist.
Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.
What to include
- Define a fixed-point question and record session effort.
- Apply the supplied teaching key without forcing uncertain IDs.
- Count distinct individuals using movement evidence.
- Compare sessions with duration, weather, and nondetection limits.
- Label all practice data fictional and complete the eligibility audit.
Review and revise
Use these criteria to check your work and choose what to improve.
- Dates, durations, protocol, and distance follow the supplied rules.
- Identification and count decisions match the evidence.
- Comparisons avoid population and absence overclaims.
- The submission checklist excludes invented and ineligible records.
Want more background?
The idea in everyday life
Fictional S1 notes: 8:11 two A birds sit together; 8:12 the same two fly to a nearby branch; 8:14 one additional A arrives while both originals remain visible; 8:16 two B birds appear together; 8:18 B birds leave and a blue-patched bird with hidden bill appears, identity uncertain. For this exercise no other A or B individuals are detected.
Count birds, not the number of times they catch your eye.
Count without double-counting: guided practice
Count birds, not the number of times they catch your eye.
Use paper or a free local text editor. This is an original fictional practice case; do not submit its records to a real service. Start this lesson with these facts, even if an earlier variation changed them. Fictional S1 notes: 8:11 two A birds sit together; 8:12 the same two fly to a nearby branch; 8:14 one additional A arrives while both originals remain visible; 8:16 two B birds appear together; 8:18 B birds leave and a blue-patched bird with hidden bill appears, identity uncertain. For this exercise no other A or B individuals are detected.
1. Track the A birds
Follow the explicit same-bird and additional-bird statements.
You should see: A count: 3 individuals.
The same two birds changing branches do not add two new individuals.
2. Track B separately
Count the two simultaneously observed B birds.
You should see: B count: 2 individuals.
A count should be tied to evidence of distinct birds.
3. Preserve the uncertain sighting
Record the later blue-patched bird without adding it to B.
You should see: One unidentified observation; whether it is a previously counted B is unknown.
Uncertain identity and possible reobservation should not inflate species counts.
4. Write the counting note
State counts and the reason repeated A sightings were not added.
You should see: A=3; B=2; repeated views excluded; later unknown kept separately.
A short method note makes the count auditable.
What to finish
Count without double-counting record with the worked decisions and changed-case check.
Watch for this
Adding every sighting as a new bird or inventing an exact count.
How can I tell I understand it?
Track individuals using supplied movement evidence and distinguish unknown counts. Explain the evidence behind the result and correct any mismatch.
Quick knowledge check
Answer all 3 questions. Get at least 2 right and the lesson completes automatically.
You’ll get an explanation for each answer. Signed in? Your results save to your account.
Pass the check. We’ll save the progress.
Answer all 3 questions above and get at least 2 right. You can review the explanations and try again.
Go to the knowledge checkOptional course overview video · same video as Lesson 1
Submit Your Sightings on eBird Mobile - eBird Essentials
From Cornell Lab of Ornithology. Watch here or open it on YouTube .
Optional course overview. Follow the written steps below at your own pace.Tools, templates, and lesson sources
Tools and templates
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Sources and further reading
Explore the references behind this lesson.
Source & access notes · checked 2026-09-12
Inspected complete checklists, counts, and prohibition on synthetic, other-person, and remote-camera records.
Access: Public page or PDF inspected without payment or institutional sign-in on September 12, 2026. Optional external accounts are unnecessary for this course.
Reuse: Link and original paraphrase only. Public access does not grant blanket reuse; no provider text, figures, or exercises are reproduced.
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