Andrew Bird has a way of making things seem easy. Such is the disarming sense of grace and confidence on the Chicago singer/multi-instrumentalist’s fifth solo studio album, it takes a while to note the complexity of what he achieves so casually. When he’s not fusing whimsical humor, swelling strings, and a bossa-nova swagger on “Masterswarm,” he’s applying his signature croon to machine-made beats and fuzzier noises on “Not a Robot, but a Ghost,” or inventing his version of a pastoral-folk symphony in “Souverian.”