Protected areas (PAs) are widely recognized as being essential for maintaining global biodiversity. In this study, I aimed to determine whether PAs support a greater richness of forest bird species than unprotected habitats and whether they exhibit functional diversity indices and traits comparable to those found in protected forests in the eastern Brazilian Semideciduous Atlantic Forest. I conducted bird surveys across 20 forest fragments of varying sizes (43 to 37,000 ha), 12 of which were legally designated as PAs. The results indicated that species richness was not significantly higher in PAs and that there were no significant differences in functional diversity indices and traits between unprotected and protected forests. In eastern Brazil, some forest remnants were designated as PAs merely because they were among the last remaining patches within a heavily fragmented landscape. Therefore, protected areas do not necessarily serve as accurate proxies for well-preserved habitats.