Carolina Wrens (Thryothorus ludovicianus) & House Wrens (Troglodytes aedon)
Carolina Wrens are harmless and welcome to nestboxes. House Wrens like to puncture other bird eggs and throw them out. Both are native, protected species. I don't have to deal with House Wrens here in SW Arkansas, but did experience them when I lived in NW Arkansas where the House Wren pics below were taken.