283
NESTLING PERIOD 283
Hatching Sequence 283
Development of the Nestlings 284
Parental Behavior 285
Feeding of the Nestlings 286
Nest Sanitation 287
Fledging 287
Nest Parasites 287
FLEDGLING LIFE 288
Second Broods 288
REPRODUCTIVE SUCCESS 289
Behavior 290
Predation 291
Cowbird Parasitism 291
SUMMARY 292
LITERATURE CITED 294

INTRODUCTION

The Bell Vireo (_Vireo bellii_ Aud.) is a summer resident in riparian
and second growth situations in the central United States south of
North Dakota. In the last two decades this bird has become fairly
common in western, and to a lesser extent in central, Indiana and
is apparently shifting its breeding range eastward in that state
(Mumford, 1952; Nolan, 1960). In northeastern Kansas the species
breeds commonly and occurs in most tracts of suitable habitat.

The literature contains several reports dealing exclusively with the
Bell Vireo, notably those of Bennett (1917), Nice (1929), Du Bois
(1940), Pitelka and Koestner (1942), Hensley (1950) and Mumford
(1952). Bent (1950) has summarized the information available on the
species through 1943. Nolan (1960) recently completed an extensive
report based on a small, banded population at Bloomington, Monroe
County, Indiana. He validated for this species many points of natural
history previously based on estimates and approximations, especially
concerning the post-fledging life of the young and the movement of the
adults from one "home range" to another in the course of a single
season.

None of these reports, however, has emphasized the ritualized
behavioral patterns associated with the maintenance of territory and
with courtship. Among the North American Vireoni