Tactics and Vectors 98/99
                           

Home

Table of  Contents

Great Circle Hypotheis  

Magnetoclinic Hypothesis

Magnetic-Latitude Hypothesis

Compass Bearings Hypothesis

Suns' Azimuth Hypothesis

Expansion-Contraction Hypothesis

Always Advance Hypothesis

Never Go Back Hypothesis

 

 

Analyses of Pooled Field Data: Descriptive Statistics

Descriptive statistics for pooled directional data for 1978, 1979, and 1981 Monarch butterfly (Danaus plexippus) migrations in Southern Ontario. 

¦ Up   ¦ Tables:  ¦ I,  II,  III,  IV,  V,  VI,  VII,  VIII a,  VIII b,  IX,  X,  XI,   XII  ¦

left arrowarrow leftTable VI*

Proportion of migrating Danaus plexippus flapping, gliding, and soaring flight for eight wind conditions

Data were grouped according the category of flight behaviour (flapping, gliding, or soaring) and wind direction at the time of the observation.  

Number and percentage of migrating D. plexippus in each flight category for each wind condition.

Wind

N

Flapping  

 Gliding   

Soaring 

Num.      %     

Num.      %   

Num.      %  

North

 53

11       20.8 

4         7.5 

38       71.7

Northeast

  64 

15        23.4 

2         3.1 

47       73.4

East

150 

  37       27.4   

9         6.0 

  104      69.3    

Southeast

131 

47       35.9 

20      15.3   

  64      48.9  

South

15

11       73.3 

  1         6.7   

  3       20.0

Southwest

  35  

20       62.9 

2         5.7 

 13       37.1

West

20

  5       25.0 

3       15.0 

  12       60.0 

Northwest

107   

20      18.7 

19       17.8   

 68       63.6

Population

575   

166     28.9  

60     10.4  

349     60.7 

* Adapted from Gibo, D. L.  1990

Definitions of abbreviations and symbols:  N = number in sample,   Num. = in  flight behaviour category.

Comments  

  1. Maximum proportions of flapping migrants were observed with South and   Southwest winds.  A South wind is a combination headwind and left crosswind to a Southwest course.  A Southwest wind is a direct headwind for a Southwest course.

  2. Maximum proportions of soaring migrants were observed with North, Northeast, and East winds.  A Northeast wind is a direct tailwind for a Southwest course.  A North wind is a combination tailwind and right crosswind, and an East wind is a combination tailwind and left crosswind, to a Southwest course.

  3. The butterflies seldom migrated during periods of Southwest winds.   Most of the observations for SW winds were made during one morning when mean wind velocity at 1.5 m was 0.8 m/s.