Azure Tit Cyanistes cyanus (prev. Parus cyanus)
The Azure Tit is native to most of Russia and Central Asia. It is closely related to the Blue Tit.
Bringing a caterpillar to the nestlings. Male and female have similar plumage.
The alien (head-on).
This pair were nesting in an upright pipe and both bringing caterpillars to the young presumably inside.
The photos in the row immediately above are from Alexandra Makhnina, who returned to the same nesting place 2 years later.
More photos, above, from Alexandra Makhnina.