That is a fake hallmark
Sorry, that is not a fake hallmark. It is a perfectly legitimate maker's mark. Over the years, I've noted that there were a number of Mexican smiths that used pictorial, rather than letter initial or full name makers' marks. The most notable are Conquistador of Mexico City (knight/horse) and Chato Castillo (parrot head). The fact that these high profile silversmiths used pictorial marks lends credence to the legitimacy of the practice.
The fact that this eagle head maker's mark shares a body part with the Mexican Assay stamp can only be noted as coincidental. As mentioned in another post - to be a false or fake mark, the mark must resemble the one it is supposed to mimic.
Certainly there exist Mexican pieces with faked marks, just as they exist in every other genre of jewelry and silverwork. The bracelet shown here is marked "Sterling", if it is lower grade than 925 or made from alpacca, the only justifiably fake mark it bears is the "sterling" stamp.