This is the coat of arms of the Republic of Panama. It is over the main entrance to the palace.

The Panamanian poet Ricardo Miró (1883-1940) gave President Belisario Porras 2 herons.
He wrote a poem for the occasion:

"En el Patio Andaluz, a donde apenas penetra el sol en ondas fugitivas, inmóviles, calladas, pensativas, hay, como un par de enormes azucenas, dos garzas melancólicas, cautivas."

Hence the name Palace of the Herons.

Their descendants can be seen there to this day.