Building a Nursery
The robin will weave this dead grass together with mud as she builds her nest—a nursery for her babies. Dead grass is easy for robins to pull from the ground. She'll bring mud to hold it together, but mud can crumble when dry. The job of the grass is to make the all the nest materials hold together so it's strong enough to last for the weeks of egg laying, incubating and raising nestlings. After that, the robin builds a new nest for the second brood. A less ambitious robin might repair and use the nest again.

Image: Wayne Kryduba