The swan pictured is a Trumpeter Swan, the largest of all swan species and the most defensive. In fact, it does not belong in Maryland, but federal and Maryland state wildlife officials killed all Mute Swans in Maryland except two mating pair in Chesapeake Bay so they could introduce the larger Trumpeter Swans for Trophy Waterfowl hunting purposes.

Because this swan is so large, it can intentionally or inadvertently kill other swans and waterfowl due to its shear size. Both swans may be males and the alpha swan is now making his case that the habitat is his and his alone. The male swan of all species usually builds the nest. So, if the swan pictured is not the one building the nest, it may be that the other swan is a male.

In any case, this is mating season and the hormone levels are high. Hopefully, if the other swan is a female, things will settle, they will mate and nesting will occur. If both swans are male, hopefully, the other male will leave and not be harmed. The Regal Swan