ChirpScout

ChirpScout Migration Study

Spring & Fall 2021–2025 · Triangle · Asheville · Coastal NC
This study informs ChirpScout — a birding app that helps you find the right place at the right moment to see the most birds. Learn more →

Study Overview

5-year spring & fall migration study · Three North Carolina sites · April–May + August–November · 2021–2025

From 2021 through 2025, we analyzed over 100,000 eBird checklists across three distinct North Carolina regions — the Triangle (Wake County), Asheville (Buncombe County), and the Coastal Plain (New Hanover County) — spanning both spring (April–May) and fall (August–November) migration windows. The goal: understand when birds move, where they concentrate, and what combinations of temperature, wind, precipitation, and post-frontal conditions predict the most active birding days. Daily weather records were matched to each checklist date, allowing us to quantify how environmental conditions correlate with observed bird activity across all three sites and both seasons.

Where the data is clear and consistent, those findings have been incorporated into ChirpScout's suitability scoring — the formula the app uses to tell you whether today is worth heading out. The Activity Validator tab shows exactly how the app score compares to what similar days in this dataset actually produced.

Use the tabs above to explore migration timing, species diversity curves, warbler detection heatmaps, and top-ranked hotspots. The Activity Validator lets you enter your zip code and see how today's conditions stack up against five years of observed data in real time.

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Migration Timing

Which weeks are consistently the best at each site? Averaged across all five study years. Use the Season filter in the header to switch between spring and fall views.

What is phenology? Phenology is the study of recurring natural events and their timing — in this case, when birds arrive and peak during migration. Just as a gardener tracks the first bloom, birders track phenology to know the best week to visit a site. Elevation shifts timing in both directions: Asheville's spring peak is 1–2 weeks later than the Triangle (cold mountains delay arrival), while its fall peak is 1–2 weeks earlier (birds descend from higher ground sooner as temperatures drop).
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Species Diversity Over Time

How does the number of unique species change across the migration season? Each line is one site.

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Warbler Wave Tracker

When do warblers move through? Detection rate (% of study years a species was recorded) by week.

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Hotspot Leaderboard

The most species-diverse birding locations across the study period, ranked by total unique species detected.

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Activity Validator

Enter a zip code to pull current weather, then see how today's conditions compare to similar days in the study — grounding ChirpScout's suitability scoring in real observed data.

Current Conditions