While most host species are unable to distinguish cowbird eggs from their own, some do. Larger species are often able to puncture the cowbird egg or nudge it out of the nest.

While most host species are unable to distinguish cowbird eggs from their own, some do. Larger species are often able to puncture the cowbird egg or nudge it out of the nest.

Reuse of ephemeral open cup nests by passerines is an uncommon behavior. We report the first case of nest reuse by federally endangered black-capped vireos (Vireo atricapilla). The initial use of the ...