I am not sure how many aphids these guys can consume on a given day, but I watched one last year spend a good half hour doing nothing else. The aphids were heavily infecting a plum tree in the orchard, as they often do, but my little buddy noticed them before I did. In fact I wasn’t even aware of them until I happened upon that scene.
The Blackcapped chickadee (Poecile atricapillus) is very common in deciduous forests and clearings. You can encourage them by by provided diverse plantings, reducing or eliminating pesticides, and allowing enough cover for nesting. On this last point, leaving some dead and decaying trees in the lot can help these and other birds that will use excavated cavities as nesting sites. They will often nest 5-20 feet in the tree. Providing a habitat that mimics natural places will go a long way toward encouraging the presence of helpful animals.