tory.
Red-eyed Vireos require five to six days to choose the first nest-site
(Lawrence, 1953:54). Later sites of the Bell Vireo are chosen in as
little as three hours. Nest 1-c (1960) was abandoned at about 11:00
a.m. on May 14, 1960, when part of the thicket on the edge of which
this nest was located was removed by brush-cutters clearing a power
line right-of-way. By 2:00 p.m. this pair had begun construction of
1-d (1960) in an Osage orange 110 feet southwest of 1-c (1960).

This particular site is of further interest because it is the same one
utilized for nest 1-a (1960). In all, four instances of utilization of
a nest-site a second time were recorded. Two-a (1960) and 2-d (1960)
were built in the same fork; 1-c (1960) and 1-h (1960) were in the
same tree, but not the same fork. It should be mentioned that 1-a
(1960) and 2-a (1960) were abortive attempts that did not progress
beyond the suspension apparatus. Nice (1929:16) recorded a similar
instance of the re-use of a nest tree, but different forks were used.

Re-use of an exact nest-site would ordinarily be impossible if the
initial attempt were not abortive, because the presence of a completed
nest would pose problems in construction with which the birds would
probably be unable to cope. (A report by Morse in Bent, 1950:256 of a
double nest indicates that this may not always be true. At the time of
discovery one nest contained two eggs and the other nest contained
young.) Since nests are used only once there would be no tendency to
adopt the old nest. However, abortive nests, usually little more than
a few strands of nesting material secured to the fork, might stimulate
the birds to continue building. Re-use of a single nest-site in 15.8
per cent of 38 nests built in 1960 seems to be more than fortuitous
circumstance. This re-use may have physiological benefits in
conjunction with apportionment of energy for other nesting activities,
because rapid location of a nest-site would mean that energy normally
expended in searching and selecting could be rechanneled for actual
construction. In each of the instances of rebuilding, the new nest
was begun on the same day that the previous nest was abandoned.

The re-nesting of pair 9 (1960) is worthy of note. These birds were
established in the elm thicket on Clark land. Elm was by far the most
abundant tree, with dogwood, Osage orange and honey locust also
relatively common. There were only six boxelders in the territory