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Calcimator

Migration Pattern Calculator

Predict flyway timing, stopover duration, and migration windows for migratory bird species based on location, season, and species group.

Inputs

°N
mph
grams

Results

Current Migration Status

Spring Migration (3% through)

Spring Peak Date

Apr 27

Fall Peak DateSep 14
Spring Migration WindowApr 9 – May 15
Fall Migration WindowAug 27 – Oct 2
Adjusted Flight Speed61 km/day
Estimated Migration Distance2,200 km
Total Migration Duration108 days
Avg. Stopover Duration4 days
Total Energy Cost277 kJ
Stopover Frequency10
How to Use This Calculator
  1. Select Flyway (Atlantic, Mississippi, Central, or Pacific) for waterfowl, or the relevant corridor for other species.
  2. Choose Species Group (waterfowl, shorebirds, raptors, neotropical songbirds) for species-specific timing data.
  3. Enter Observation Latitude (°N) — latitude drives phenological timing within each flyway.
  4. Input Current Day of Year (1-365) to see current migration status relative to historical peak dates.
  5. Set Average Tailwind Speed (km/h) and Average Body Mass (grams) to estimate daily flight range.
  6. Review Migration Status, Spring Peak Date, and daily flight range estimates for survey planning and hunting season timing.

What each input means

Flyway
1 = Atlantic, 2 = Mississippi, 3 = Central, 4 = Pacific.
Species Group
1 = Waterfowl, 2 = Shorebird, 3 = Songbird, 4 = Raptor, 5 = Seabird.
Observation Latitude
Latitude of your observation location (degrees North).
Current Day of Year
Day of year (1 = Jan 1, 100 = Apr 10, 200 = Jul 19, 300 = Oct 27).
Average Tailwind Speed
Average tailwind component. Use 0 for headwinds. Tailwinds significantly extend flight range.
Average Body Mass
Average body mass of the species. Warblers ~10g, ducks ~1000g, geese ~4000g.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Flyway = 2, Species Group = 3, Observation Latitude = 40, Current Day of Year = 100 = 6 input(s) provided
  2. Calculate Current Migration Status
    Spring Migration (3% through) = Spring Migration (3% through)
  3. Calculate Spring Peak Date
    Spring Peak Date = dayToDate(springPeak)
    Apr 27 = Apr 27
  4. Calculate Fall Peak Date
    Fall Peak Date = dayToDate(fallPeak)
    Sep 14 = Sep 14
  5. Calculate Spring Migration Window
    Spring Migration Window = `${dayToDate(springStart)
    Apr 9 – May 15 = Apr 9 – May 15

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