D e s e r t E x p o s u r e
August 2009
Great Blue Heron
Page: 2The male raises its plumes and croaks softly (and romantically, at least in the eyes of the Great Blue Heron female). He gives the female a twig as if it were a bouquet of roses. The two clasp bills and move their heads back and forth, in a beakshake instead of a handshake. They preen each other's feathers affectionately.
They mate sporadically, in very brief episodes, over the next several days. Within a few weeks after their initial mating, the female lays a pale bluish-green egg, the first of four to seven she will produce during the next several days. After the arrival of the first egg, the faithful parents take turns incubating the clutch, with each remaining on the nest for six or so hours at a stretch. This routine will play out over some four weeks, until the first pale gray downy chick hatches.
For the next several weeks, the parents must incubate the remaining eggs and, at the same time, brood and feed the demanding new arrivals. When a parent returns from a foraging trip with food, the bird usually takes a perch a few feet away from the nest, perhaps steeling itself for the coming raucous feeding. Meanwhile, the nestlings bob up and down, jostle and peck, squawking excitedly.
After several minutes, the parent flies to the nest and regurgitates food into the beaks of the rioting baby Great Blue Herons or onto the floor of their nest. The older and larger chicks bully the younger and smaller siblings in the scramble for food, sometimes pushing them from the nest to fall to their doom. Often only two or three of the sibling herons manage to survive.
Within a couple of weeks, a young heron begins to preen itself, stand upright and spread its wings. After a few more weeks, it ventures from the nest, a gangling adolescent, spreading and flapping its wings. Soon, it makes exploratory flights to nearby trees or to the ground, always returning to the comforting refuge of the nest and parental feedings.
About two and a half months after hatching, the young Great Blue Heron leaves its nest for good, setting out on a life of its own. If it survives the hazards of youth, when it is most likely to fall prey to crows, ravens, turkey vultures, red-tailed hawks, eagles, raccoons and human land development, it will take up the art and pleasure of solitary fishing and the annual rewards and trials of parenting.
Its parents, meanwhile, will dissolve their union when their last chick leaves the nest. They will each return the following year to pursue a new romance with a new mate.
A large bird, the adult Great Blue Heron has few natural enemies other than humans, and its overall population remains relatively healthy in the desert Southwest. But the bird, which has a low tolerance for human encroachment, especially when nesting, may face an uncertain future in the wake of booming urban and suburban development.
Thoreau once held the Great Blue Heron in such high regard that he felt it should be made "a citizen of America." Today, the Great Blue Heron will serve as a measure of how well we manage and care for our water resources in the desert Southwest.
Jay W. Sharp is a Las Cruces author who is a regular contributor to DesertUSA, an Internet magazine, and who is the author of Texas Unexplained. For more on spotting water birds in the desert Southwest, see his article "Testing the Waters" in the July 2009 issue.