Pie Sw DU BON BULLETIN 
Published Quarterly by the 
isin Less ASU D UPB ON, 2S.0,6 LEVEY 
ROOSEVELT ROAD AND LAKE SHORE DRIVE, CHICAGO 5, ILL. 
Number 118 June, 1961 
The Belligerency of a Pair of Wood Pewees 
By MARGARET MorsE NICE 
Most oF US WOULD agree with Bent’s (1942:173) statement on the Wood 
Pewee that “It is a seclusive, apparently peace-loving little bird, quiet, al- 
though very quick in its motions, and seldom asserts itself, being wholly 
free from the aggressiveness that marks the behavior of some of the larger 
flycatchers.” Such an impression stems naturally from the sweet and plain- 
tive daytime notes of this bird — phrases 1 and 2 — and the exquisite 
beauty of the twilight song in which phrase 8 plays the leading role in 
combination with 1 and 2 (Craig, 1943). Inspired by Dr. Craig, I have 
listened to and recorded this song in Massachusetts, Illinois and Oklahoma. 
It was indeed a surprise to me to find the marked hostility of two parent 
Wood Pewees towards most other birds. On July 26, 1950, I had the good 
fortune to discover a nest of Contopus virens on Wooded Island in Jackson 
Park, Chicago. The nest was 12 feet up in a small bur oak, and both 
parents were feeding the two young. From the moderate amount of brood- 
ing seen on this and the two following days, and from the fact that the 
young left 11 days after the finding of the nest, I judged them to be about 
five to six days old. Bent (1942:271) gives an instance of a single nestling 
leaving on the fifteenth day, while Kendeigh’s (1952:110) brood of three 
left at 16 or 17 days. I sat on the ground 30 feet east of the nest and 
watched both with and without my binoculars. The parents paid no atten- 
tion to me even when I walked directly under the nest. Gabrielson’s (1922) 
pair were equally indifferent to human beings. I spent an hour on the 26th, 
two hours on each of the next three mornings, an hour each day through 
August 4, and two hours on August 5 — 15 hours in all while the young 
were in the nest. On August 7 I watched the family one-half hour, on the 
9th an hour. The 15 hours were all in the morning from 6:12 to 11:08, 
central standard time; the two later sessions in the early afternoon. 
Most of the time the parents were distinguishable, especially in good 
light — partly by behavior, for she alone brooded and he alone sang, and 
partly by appearance, for her breast feathers looked somewhat ruffled in 
contrast to his trim lines; also his head was darker than hers. Until the 
last four days of nest life I was able to credit most of the feeding visits 
to the proper parent, but after that feeding became so rapid that I often 
had to record only a “‘p” for parent. In regard to other activities there was 
no difficulty in distinguishing the sexes. 
Both parents had a favorite stance where they perched singly or to- 
gether; this was a dead branch about three feet below the nest. They also 
watched for prey from dead branches in a nearby silver maple and at the 
very top of a great Carolina poplar. 
[1] 
