The birds you see in the pictures are cleaner birds, called oxpeckers. These birds feed on the parasites that live on the hides of animals such as rhinoceroses, elephants and zebras. For this reason, these birds' perching on them, even on their heads does not annoy such animals.
This partnership benefits both sides a lot. In this way, the animals get rid of bothersome parasites and are also warned by the birds, which screech in case of danger. In return, the birds obtain food and even hair to cover the inside of their nests.
Allah created this mutually beneficial relationship between animals. Allah created all these creatures along with the creatures that meet their needs.