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yur resident birds began to come to the feeders as in mid-winter. Their 
vatural insect food was gone. But our records of migrants were the 
owest in history and our summer nesting birds were scarce indeed. 
Where there are normally indigo bunting every few hundred feet 
long the road, there were none all summer. With Alex and Fred, 
walked in and out the mile-long trail to the Owl’s Head in late 
july and we heard just four birds— a downy, a titmouse, a red-eyed 
reo and a towhee. Whether the spraying killed the birds or only 
heir food, we do not know. We picked up no dead birds. But the 
mmediate effect was the same: There were almost no summer resident 
rds at the sprayed part of the Sanctuary this year. For the future, 
ve will just have to wait. And—to go back—a week or ten days 
ifter the Sevin spraying, millipedes were just starting to die. Possibly 
sevin is not as non-persistent as claimed ...” 
(Comment by Ingram: There is a possibility that neither of these 
micals acting alone would have been lethal in amounts much, much 
Her than a lethal dosage of either single chemical. This is one of the 
htening facts that man is gradually discovering in his research with 
cticides. Two or more chemicals have a lethal level much lower if 
y are mixed together than if they are given singly.) 
“Did this spraying stop the gypsy moth invasion? No. The State 
eported more egg clusters than before. 
“Was there tree defoliation in the sprayed areas? No. But in an 
rea a few miles to the west where the moths were discovered after it 
vas too late to spray, there was much defoliation in late June, but 
y mid-August these trees had almost completely refoliated. We do 
ot know for sure whether defoliation and refoliation over a period 
f several years will result in substantial tree kill, but our best evi- 
lence is that, except for old or diseased trees, it will not.” 
Two hearings on the subject of this spraying were held under the 
ctorship of Senator D. Elmer Hawbaker. The following three themes 
e developed during the second of these hearings. 
“First—we were disappointed that the Senators, in spite of their 
bvious interest and desire to come up with a solution to the problem, 
ad difficulty in grasping the concept that the very fact that there 
re many unanswered question about the various pesticides is, in and 
f itself, what makes their use so dangerous. They seemed to take 
he position that a pesticide should be considered harmless until 
here could be definite, direct proof to the contrary. 
“Time and time again we were asked for direct proof that DDT 
r Sevin or Dylox was harmful other than to insects. They seemed 
9 regard the fact, for example, that the Bermuda Petrel reproduction 
ate was declining, that their eggs were infertile or their chicks died 
nmediately upon hatching, and that the eggs and chicks contained 
igh concentrations of DDT, as circumstantial rather than direct 
vidence. They were disappointed that we raised so many questions 
nd had comparatively few answers, but we hope we finally succeeded 
1 getting across to them that this is the heart of the problem. 
“Second—Among all the biologists and ecologists there seemed 
) be agreement on the need for further and intensive study of the 
ossibility of biological controls of harmful insects and the desir- 
