Looks like someone splashed fluorescent paint on the rock. A lichen that screams for attention. The colour is a loud, unapologetic yellow – bright orange-yellow in the sun, fading to paler yellow in the shade. The lichen of the bird perch, the one that grows where seagulls sit and nutrients drip. If a bright yellow patch is seen on a rock, look up. There is probably a bird sitting above it. A lichen that is a sign of bird droppings. What makes it special is the colour. One of the brightest lichens in New Zealand. The colour comes from a pigment called parietin, which acts like a sunscreen, protecting the algae from intense sunlight. The more sun, the yellower it gets. In the shade, it fades to a pale, greyish-yellow. The chameleon of the lichen world, turning up the colour when the sun is bright. The body is leafy and lobed, forming circular rosettes or spreading patches on the rock. Lobes are broad and rounded, often overlapping like flower petals. Margins are covered in tiny, powdery granules (soredia) that break off and grow into new lichens. A master of reproduction, a plant that spreads by crumbling. A partnership – a fungus and an alga living together. The fungus provides structure and protection; the alga provides food through photosynthesis. But it is also a nitrogen lover. It thrives in nutrient-rich environments – bird perches, the tops of fence posts, the splash zone of the sea. To find yellow sunburst lichen is to find a splash of colour on grey rock. The rock is grey. The lichen glows, bright yellow, a splash of fluorescent paint. A seagull sits above. The nutrients drip. The lichen grows. It does not know it is loud. It does not know it is unapologetic. It just wants to be in the sun. The yellow sunburst, the bright one, the one that screams "bird droppings nearby." That is its job.