The Double-Crested Cormorant: Symbol of Ecological Conflict

3. Flight: When a Dinosaur Looked Down upon Gravity

3  Flight When a Dinosaur Looked Down upon Gravity the cormorant is a persistent goal seeker throughout its life cycle. Cormorants do not give up. They adapt. These birds, as examples of adaptive evolution, embody the ability to maximize their use of the environment to survive and prosper. In modern times, Phalacrocorax auritus, the double-crested cormorant , exploits the environmental worlds around it: it swims on the water’s surface, dives to its depths, nests and perches on land, and ›ies. The double-crested cormorant was and continues to be successful because it exploits the opportunities offered in each of its four worlds and copes with the dangers each one poses. The violence perpetrated on cormorants was often committed out of a perception of what was happening rather than the reality of actual situations . Early misconceptions of the bird itself caused many of the con›icts. The mistaken beliefs and gothic folklore are to double-crested cormorants what the imagery of Woody Woodpecker, the 1940s zany, red-headed cartoon character with its staccato call, is to the reality of its natural counterpart, Dryocopus pileatus, the pileated woodpecker. The one had little relation to the other; the comparison was an overdramatization and exaggeration, used with a speci‹c purpose in mind. Entertainment is entertainment, and its distortions create con›ict and drama, 28 which is exciting, but science is science, and distortion and exaggeration create con›icts where none needs exist. It’s easy to condemn a species like the cormorant for apparently disrupting the ecosystem, but if they are not indeed the culprit then the issues remain unresolved. To value the genuine nature of the cormorant, in this and the next few chapters, we’ll look at its niche in today’s ecosystem and how it got there. Sometimes it’s easier to understand an animal, particularly an “eccentric ” species like the cormorant, by looking at its more conventional relatives and its ancestors. One discussion of the implications of animal evolutionary relationships, what scientists call phylogeny, stated that the “pattern of animal interrelationships has profound consequences for understanding the underlying processes of animal diversity.”1 Also pointed out was the idea that phylogenetic reconstructions, that is, the diagraming of evolutionary pathways or “trees,” are noted for their controversies , inconsistencies, and inherent uncertainties. The “trees” are models, works in progress in constant ›ux, with revisions based on new discoveries welcomed. The same article proposed that even though there is no direct experimental laboratory testing available to duplicate hypotheses of evolutionary history, it is the compilation of independent data and ‹ndings that helps classi‹cation specialists, called taxonomists , reach reasonable conclusions. The bringing together of independent ‹ndings, in the form of fossils, and scienti‹c observations helped produce the probable evolutionary background of birds in general and double-crested cormorants in particular. When biologists speak of classi‹cation and taxonomy what they are really discussing is evolution. In a convoluted way, and with a fair number of exceptions, as a rule of thumb they assume that organisms that resemble each other today most likely followed nearly identical evolutionary paths; they presumably have an ancestor common to each line somewhere in their evolutionary history. So taxonomy, above and beyond the comparison of behaviors and anatomical features, is the possible mapping of an organism’s development through the ages. In the case of the cormorant, it is a vertebrate, in class Aves, the birds. Taxonomists place the cormorant family in the same order, Pelecaniformes , as frigate birds, gannets and boobies, pelicans, snake birds, and tropic birds. The four major families, sorted by numbers of species and individuals, in some ways resemble each other but differ greatly in how each captures its food. Frigate birds use aerial pursuit in their hunt Flight • 29 of surface marine animals such as squid, compared to gannets, which capture their prey by means of a dramatic plunge into the water after hovering at a height. White pelicans use their long necks to stretch down into the water to grasp their prey from a wading or swimming position, whereas, like brown pelicans, double-crested cormorants dive to depths from the surface in pursuit of their quarry. Biological classi‹cation is not an exact science and is open to a great deal of interpretation. The conventions of classi‹cation dictate that all organisms in a single taxon, or group, share common characteristics, but the number and type of shared...