Richard was observing black swallowtail butterflies in the field. Which one of these is an observation he made about a black swallowtail butterfly?

Richard observed that the black swallowtail butterfly has striking black wings adorned with vibrant blue and yellow spots. He noted its graceful flight pattern as it flitted from flower to flower, feeding on nectar. Additionally, he remarked on the butterfly's distinctive tail-like extensions on its hindwings, which add to its unique appearance.