Birds are complex organisms with a variety of cell types, each with its own specific set of organelles. For example, red blood cells contain a large number of mitochondria, which are organelles that produce energy, while muscle cells contain a large number of myofibrils, which are protein filaments that allow the cells to contract.
The presence of nuclei and organelles is a fundamental characteristic of eukaryotic cells, and it is essential for their survival and function.