EFFECT OF PREDATION AND COWBIRD PARASITISM ON THE NESTING SUCCESS OF TWO SYMPATRIC NEOTROPICAL MARSHBIRDS

摘要

We compared the effect of nest predation and cowbird parasitism on the breeding success of two simultaneously nesting ecologically similar blackbird species that differ in their breeding strategies. The Scarlet-headed Blackbird (Amblyramphus holosericeus) is a monogamous species that performs territorial de- Fense. In contrast, the Brown-and-yellow Marshbird (Pseudoleistes virescens) is a non-territorial monogamous Breeder that performs mate guarding and has helpers at the nest. Both species suffered similar nest predation Rates throughout their nesting cycle.