MONTHLY WILDLIFE RESEARCH LETTER 
Vol. 3, No* 4 
Fage 2 
F. Bellrose 
W-55-R-4 
Four aerial censuses were made of waterfowl populations in the Illinois, 
Mississippi, and Rock River valleys during the month. Survey dates were: April 
2, 5, 12, 18, 26 and 27. 
The spring migration of waterfowl, retarded by bad weather during March, 
rapidly caught up with the "calendar" during April as a result of above normal 
temperatures. Because of the compressed migration resulting from weather and 
because of floods creating tens of thousands of acres of excellent feeding grounds, 
the largest numbers of several species ever found during the spring occurred this 
April. Species which were unusually abundant were green-winged and blue-winged 
teal, widgeon, shoveler, and ring-necked duck. 
The flooding of tens of thousands of acres of farmland made censusing 
of waterfowl extremely difficult. Waterfowl left existing lakes and marshes 
almost en masse for flooded corn fields. Despite the extensive areas of flooded 
fields, waterfowl were not dispersed over the areas but were definitely congre¬ 
gated in certain areas. Curiously, the areas frequented by an aggregation of 
flocks composed of several species appeared no different in attractiveness than 
hundreds of other areas which held no waterfowl. 
W-56-R-4 G. Sanderson 
Live-trapping of raccoons and opossums was resumed on the Piatt County 
Study Area in April. Although the data are limited, they indicate that opossums 
may have suffered heavier than usual mortality, probably because of prolonged deep 
snow and cold during much of February and March. Even though more trap-nights of 
observation were made during April of this year than in past years, fewer opossums 
were caught. 
Mr. Udell Meyers, the new investigator on the raccoon-wood duck project, 
became familiar with the locations of trees with natural cavities which had been 
previously located and marked on maps and found some new cavities believed suitable 
for wood ducks. He checked all 130 natural cavities on the study areas. 
Wood ducks arrived 2 to 3 weeks later than usual and were correspondingly 
later in beginning their nesting. Nine nests were found in natural cavities up to 
the last week in April, whereas during the same period in 1959, 24 nests were 
found. Three of the nine nests have been destroyed by raccoons; three are being 
incubated; hens are still laying in two; and one is apparently an unincubated 
dump nest. 
W-61-R-3 F. Greeley 
J. Ellis 
Hen pheasants, placed on experimental diets containing 0.75 to 2.00 per 
cent calcium and 0.3 to 0.9 per cent of available phosphorus, began laying on 
