Canadian Atlas of Bird Banding

Additional details on data coding and analysis

1. Distance and bearing

Distance and bearing were calculated using equations in Cowardin (1977), where:

  • BLAT = banding latitude
  • BLON = banding longitude
  • RLAT = encounter latitude
  • RLON = encounter longitude
  • P = BLON – RLON

Note: if Southern Hemisphere, set latitude to negative if Eastern Hemisphere, set longitude to negative if P > 180, then set P = P – 180

Distance (D) between banding and encounter in degrees was calculated as:

  • D = acos{[sin(BLAT)sin(RLAT)] + [cos(BLAT)cos(RLAT)cos(P)]}

The bearing (C) was calculated as:

  • C = ahav{sec(BLAT)csc(D)[hav(π/2 – RLAT) – hav|D – π/2 + BLAT|]}
  • hav(A) = 0.5(1 – cos(A))
  • ahav(A) = acos(1 – 2A)

2. Direct recoveries

Encounters fitting into the categories marked with a D below were considered "direct" recoveries, whereas all others were considered "indirect." Note that direct recoveries include birds assumed to be dead (including those with "unknown" present condition) plus all birds encountered at the site of banding within 90 days.

Direct recoveries
    Banding month
Year Recovery
month
JA FE MR AL MA JN JL AU SE OC NO DE
Banding yr. JA D - - - - - - - - - - -
FE D D - - - - - - - - - -
MR D D D - - - - - - - - -
AL D D D D - - - - - - - -
MA D D D D D - - - - - - -
JN D D D D D D - - - - - -
JL D D D D D D D - - - - -
AU D D D D D D D D - - - -
SE - - - D D D D D D - - -
OC - - - D D D D D D D - -
NO - - - D D D D D D D D -
DE - - - D D D D D D D D D
Banding (year + 1) JA - - - D D D D D D D D D
FE - - - D D D D D D D D D
MR - - - D D D D D D D D D
AL - - - - - - - - - - - D
MA - - - - - - - - - - - D
JN - - - - - - - - - - - D
JL - - - - - - - - - - - D
AU - - - - - - - - - - - D
Date Modified: