Why the imperial eagle has a red beak
The imperial eagle is represented until today as a black eagle on golden ground, and it has red catches and a red beak. This seems odd, because how could you come to the idea to give an eagle – which actually has a brown-yellow beak – the color red? In the early days of Heraldry the eagle was shown only black on gold, but some depictions show the armors (beak, tongue, catches [claws]) in gray.
Coat of arms of the Holy Roman Empire of German Nation
Coat of arms of Germany
Durable Black was readily available, it was made from soot. Other colors just did not, or they were not durable enough. Emperor Frederick II. was not only a great observer of nature, but also a friend of the birds of prey and falconry, which is expressed in his falconry-book. Maybe that the desire to represent the armor of the imperial eagle in natural colors goes back to him. This could have been done well, because a brown-yellowish color of minerally pigmented base was certainly available. However, to make durable, there is needed a undercoat, namely red lead. Red lead is by heat altered white lead, which was thick rubbed with linseed oil. It is until today used as anti-rust undercoat. The over the red lead applied brown-yellowish color will eventually have been exfoliated, and the durable red lead appeared on beak and claws, and thus was determined the image of the imperial eagle in the future. A representation of the armor in natural colors may well have been intentional, because we have not not forget that the here described development may have occurred in the early heraldic period, where did not yet exist this many coats of arms which were subjected under the clear rules of heraldry, where natural colors were clearly secondary.
Coat of arms of the Palatinate of Saxony
Coat of arms of Brandenburg
In the heydays of heraldry, it became the privilege to use a coat of arms with an eagle on it, and to allow distinctions, the colors of the background, the eagle and of it's armor were designed color varied.
Source: Jürgen Kaltschmitt, Volker Preuß
