The Graffiti Artists - The Double-crested Cormorant

There is no shortage of disparaging labels cast upon the Double-crested Cormorant (Phalacrocorax auritus). The heavy-bodied, diving piscivore has been called a nuisance, a villain, a monster and a fish terrorist, mostly by fishermen and mostly undeserved. I call them nature’s graffiti artists. Their roost is their canvas. Their feces and cloaca is their paint and paintbrush.

The name cormorant comes from the Latin “corvus” and “marinus” or Raven of the Sea. Considering the large congregations of birds that roost together, the fish-eating cormorant is seen as a threat to anglers and the fish they seek. While studies have shown that this threat is often exaggerated, cormorants can have an impact on the vegetation they roost upon as well as the other species that might inhabit the same trees (and usually lower than the canopy-loving cormorants).

Over the last few decades, the cormorant population in North America has dramatically increased, a heralded consequence of the ban of the harmful pesticide DDT. Like most fish-eating birds, cormorants suffered the effects of the chemical that bioaccumulated through the food chain and resulted in their inability to lay eggs with sufficiently calcified shells. Cormorants, eagles, osprey, pelicans and others would attempt to incubate their eggs and crush them instead. 

Here in South Florida I have seen a colony of 40-50 cormorants routinely roosting in the same Pond Apple (Annona glabra) trees and over time, the acidic feces they leave behind has defoliated the trees. The herons and egrets that might have nested here are forced to find a more suitable location.

In the 10,000 islands of the Everglades National Park, the cormorants, with hooked beak held high, sit upon the channel markers and leave the tell tale white washing upon the signs, inadvertent artistry that remains on display when the cormorants fly off and then swim for a meal.

Call them vandals of vegetation if you must but I prefer to look at the droppings left behind as a clue as to who was here when the bird is not.