No. All living birds are endothermic—commonly called “warm-blooded”—meaning they generate and regulate body heat internally rather than relying mainly on the environment the way reptiles and amphibians do.
Some birds do temporarily lower metabolism and body temperature in a controlled state called torpor (seen in hummingbirds, swifts, nightjars, and others), which can look “cold,” but that is still regulated endothermy, not true cold-bloodedness.
Source: Stanford Birds — Temperature Regulation and Behavior