January, 1947  A PHENOLOGICAL RECORD FOR SAUK AND DANE COUNTIES, WISCONSIN

 
 
      Days late 
      Days early   Average 
   37 28 39 30 41 42 43 44 49  37 38 39 40 414243 44 4.6 
APRIL 
   .o26. Silver Maple   40.Alder 
 
   t            I\!41 
 
   10 
       2     , 'I /,      P            / 
 
 
  1/- 
  20 
 
MAY 
  2o 82. Birdfoot Violet 129. Columbine 
  /8    4A7 7.     .1              f    /6.2 
 
 
 
  /0 
  8                        .             ij 
 
 
JUNE 
  20 155, Wild Rose 
  t5    .4 9.3 
  /0 
 
  /o 
  5 
  /0 
  /0 
  20 
 
JULY-AUGUST 
  20 24)1. Butterfly Weed 
 
  /0 
 
  1o 
  /5 
  20 
  37 38 39 40 41 42 43 44 495 
 
 
159. Soiderwort 
   4A6.7 
 
 
 
 
 
 
 
 
276. Liatris 
   4 55. 
 
 
PLANTS 
 
 
lEEN:     o-----o auk 
            o.-.. Dane 
 
 
37 3e 39 40 4142 43 44 45  J7 38 39 404142 43 44 45  37 389 40 4142 43 44
45 
 
 
48. Nepatica 
 
 
 
         IIQ 
     A| 
 
 
 
 
 136. Toadflax 
   4-6.7 
 
 
 
 
 
 
 
 
 166. Anemone 
   A- 72 
 
\A 
   V V 
 
 
 
 
 
277 Earl. Goldenrod 
    ?436 
 
%fA        c4 
 
 
6/ Bloodroot 
 
0 
 
 
 
 
 
 
 
/37 Shooting Star 
     .6. 
 
 
168. White Clover 
   4...'2.4 
 
 
298. Lesser Ragweed 
    A .0. 
 
 
37 38 39 40 41 42 43 44 4ý  37 39 39 40 41 42 43 44 48   37 38 S9
40 41 42 93 44 45 
 
 
7/. Marsh Marigold 120 
  4-=73           -/8! 
 
     01 
 \i          l\q  
 
 
      V           -/0 
 
                  -20 
 
 
146. Sheep Sorrel 1-20 
 
 
 
 
                  - /0 
                  - is 
 
 
 
213. Black Eyed Susan -zo 
        -d-74      /8j 
        A /0 
 
 
 
                  -20 
 
 
308. Closed Gentiont -2 
   .d -4.3        .16 
                   to 
                   - 0 
 
                   5-0 
                   .15 
                   20 
973839- 4 Z- 3 4 45 
 
 
FIG. 7. Deviations from Average Date of First Bloom in 20 Plants, 1937-1945.

 
 
  It is clear that in these six birds the deviation 
from their own average arrival date is less than 
half that characterizing other birds arriving during 
the same month. 
  Deviations in four non-turbulent forbs are com- 
pared with other plants blooming during the same 
month as follows: 
 
 
Sheep sorrel ...... _ 
White clover ......... 
Early goldenrod ... 
Closed gentian ------ 
 
 
                      A verage 
           (Sept. 1) Deviation of 
Month      Deviation   others in 
                     same month 
           4.5 days    6.6 days 
.May       2.4         7.6 
.June      3.6         5.9 
 
 
-July 
 
 
4 forbs above, May-August ........ 
11 other plants, May to August. 
 
 
4.3                  x 
3.8 days 
....................  7.3 days 
 
 
  In these four forbs the deviation from their own 
average blooming date is a little over half of that 
prevailing in other plants during the same month. 
  That some plants are governed primarily by length- 
 
 
of-daylight, as distinguished from other factors of 
current weather, is by now a familiar concept. The 
phenology of these four forbs suggests that day- 
length is a heavier component in their timing mecha- 
nism- than in that of other contemporary plants. 
  The six birds present a somewhat more puzzling 
case, for all of them winter in the tropics, where 
differences in day-length are much reduced. The 
plover, of course, winters beyond the tropics, where 
the seasons are reversed.  One can only conclude 
either that very small changes in day-length suffice to 
move them, or that there is some seasonal rhythm 
controlled by some other force. 
  Of the 19 birds and 15 plants appearing in Figures 
6 and 7, white clover deviates least (2.4 days), and is 
also probably one of our most reliable records. Its 
wide distribution and abundance makes for accuracy 
in detecting first bloom, and when bloom starts in 
a single plant, the whole population soon follows. 
  It seems clear to us that, given enough data, both 
 
 
113 
 
 
Item     Species 
 
 
146 
168 
277 
308