Mud dauber nest (likely blue mud dauber)

Sheltered, dry structures such as sheds, eaves, attics, and wall cavities; often attached to wood or masonry.

Adults consume nectar and other sugary liquids. Females provision each nest cell with paralyzed spiders for developing larvae.

Females construct mud tubes or elongated clusters, place a spider and one egg in each cell, then seal it. Adults are solitary and generally nonaggressive; the small insects visible may be emerging or scavenging wasps.

Stings are uncommon and usually occur only if handled or trapped. They are beneficial predators of spiders and generally do not damage structures, though old nests can be unsightly.