This took some detective work due to the absence of captions on the stamp. But no, they are not penguins; they are indeed razorbill auks.
Razorbills are distributed across the North Atlantic, with the largest grouping found in Iceland. They tend to live in estuaries where the water is slightly less salty than the open ocean. They also like it cold – water temperatures below 15 degrees C, if you please.
Razorbills form monogamous boy / girl pairs and will breed multiple times in their pairing. Whilst their sex lives are private, their social lives during breeding season are busy, with large groupings going swimming and diving together and forming long cordons of swimming birds, which must be something to behold.
https://en.wikipedia.org/wiki/Razorbill
Stamp of the Day 