================================================================== | Number | Phase of | Behavior of | | | Bell Vireos Species | of | breeding +------+---+----+--- |conflicts| cycle |HFT[C]| S | TF | A ---------------------+---------+--------------+------+---+----+--- _Coccyzus | 1 | Nestling | | | | americanus_ | | period | -- | x | | | | | | | | _Cyanocitta | 3[D] | Nestling and | | | | cristata_ | | incubation | | | | | | period | x | x | x | x | | | | | | _Parus atricapillus_ | 1 | Prenesting | -- | x | | | | | | | | _Molothrus ater_ | 1 | Nestling | | | | | | period | -- | x | -- | x | | | | | | _Dendroica petechia_ | 1 | Prenesting | -- | x | -- | x | | | | | | _Geothlypis trichas_ | 1 | Nestbuilding | -- | x | -- | x | | | | | | _Pituophis | | | | | | catenifer_[E] | 1 | Post-fledging| -- | x | -- | x ---------------------+---------+--------------+------+---+----+--- [C] HFT = head-forward threat; S = scolding; TF = tail-fanning; A = attack. [D] Includes attack against a dummy Blue Jay. [E] The Bull Snake is here included because the vireos directed typical aggressive displays towards it. Blue Jays were vigorously attacked, especially late in incubation and throughout the nestling period of the Bell Vireo. I did not see a jay struck, but a vireo would circle one closely as it perched and pursue it when it flew, following as far as 100 yards beyond territorial bounds. The buzz, ZZ-ZZ-ZZ-ZZ, was uttered in conjunction with this harassment. A stuffed jay placed eight feet from a nest elicited threat display and displacement behavior from the owners of the nest, but no attack. Incubation had just begun at this nest. A dummy Bell Vireo placed close to another nest only momentarily disturbed the male, and the female completely ignored it. Incubation had also recently begun at this nest. At this same general stage, moreover, nesting pairs showed little inclination to harass me. _Discussion_