Effects of aerial spraying of fenitrothion on breeding white-throated sparrows.
The effects of fenitrothion on reproduction in the white-throated sparrow (Zonotrichia albicollis) was examined in a New Brunswick forest cutover in the context of control operations against the tortricid Choristoneura fumiferana. Two aerial sprays of the insecticide were given, the first at a dose of 420 g a.i./ha and the second 8 days later at a dose of 210 g/ha. The behavioural responses of breeding birds to the insecticide included territory abandonment, inability to defend territory, disruption of normal incubation and clutch desertion. The adult population was reduced by one-third, primarily as a consequence of mortality and territory abandonment after the 1st spray. Clutch size and hatching success were not significantly different between the sprayed and unsprayed (control) populations. Almost all breeding attempts (84%) at 13 nests were disrupted by the spray of 420 g a.i./ha, and reproductive success in the sprayed area was only one-third of that in the control area.