One other point to consider in figure 2 is the date when activity 
ceased completely on the singing grounds. For these two routes activity 
stopped at about the same time. The Rose Lake route is located approxi- 
mately in the south-central section of the Lower Peninsula. Gratiote 
Saginaw is about 0 miles north. Table 1h is a summary showing when 
the major part of the singing ground activity stopped. 
Table 1).--Variations among regions in time woodcock 
Singing ground activity stops 
Direction and distance Date when activity 
Route (in miles) from Lansing no longer observed 
Kellogg Bird Sanctuary SW = 5 May 30 
Rose Lake ENE = 10 June 3 
Gratiot-Saginaw : N - ho June 1 
Houghton Lake | N - 105 June 5 
Cusino Experiment Station NNW = 260 June 20 
#Located in south-central section of Lower Peninsula, 
These data seem to indicate that for 1953 most of the singing 
ground activity in the southern two-thirds of the Lower Peninsula was 
completed by the first week of June. But in the Upper Peninsula, where 
spring arrives later, woodcock activity continued at least two weeks 
longer. 
The earliest date of arrival for Michigan in spring, 1953, is not 
known. But the first singing ground count made on April 1 showed 16 
occupied grounds. This route was run near Houghton Lake. 
Additional observations provided data on activity under various - 
weather conditions, variability of hearing distance, and regularity of 
singing ground occupancy. The writer visited several singing grounds 
at various stages of the moon and during different weather conditions. 
In general the full moon seemed to have no effect on the number of 
active birds or on the length of the first period of evening activity. 
The birds stopped at approximately the same time regardless of the 
moon; however, it was observed that often the same singing grounds 
were occupied later in the night, especially on a full-moon night. 
Whether or not these grounds were being used by the same bird is not 
kno wne 
43 
