Brown Pelican

Brown Pelican by David J. L'Hoste
© David J. L'Hoste
Pelecanus occidentalis
In the 18 years following the first publication of Louisiana Birds in 1955, no bird in the state declined so dramatically and so frighteningly as the Brown Pelican. In the old days an observer could not visit any part of our coast at any time without seeing these birds in numbers splashing into the sea to catch fish or lumbering by in long, undulating lines. And breeding colonies that at different times were located at Raccoon Point at the western extremity of the Isles Dernieres, East Timbalier Island, the mud lumps at the mouth of the Mississippi River, Grand Gosier Island in the Chandeleur chain, North Island adjacent to the chain, and Isle au Pitre all within our boundaries produced most of the Brown Pelicans seen along the entire northern Gulf Coast.
Although the species ranges widely through the Gulf and Caribbean areas and along the Atlantic and Pacific coasts from South Carolina and California to Brazil and Ecuador, Louisiana quite fittingly became known as the Pelican State. A family group of the birds had the honor of being emblazoned on our state seal and thus appears on all our official documents, along with the motto Union, Justice, and Confidence. Unfortunately, the legislation that named "the pelican" as our official state bird neglected to say what kind of pelican. The oversight led one year to the appearance of the American White Pelican on Louisiana automotive license plates. And by 1958, when the lawmakers finally got around to specifying the Brown Pelican as the choice really intended, almost no individuals of the species could be found anywhere on our mainland shores!
What had happened? The change came about so suddenly and so swiftly that we do not really know. The first hint of trouble came in 1956, the year after the appearance of Louisiana Birds. From June 15 to 17, T. A. Imhof and party noted 20 to 25 dead adult Brown Pelicans around Dauphin and Petit Bois islands in Alabama and Mississippi, and on July 1, the H. A. J. Evanes counted 50 corpses on Isle au Pitre and found others on the Chandeleur Islands. Nonetheless, in the closing days of May in the following year, Robert J. Newman and P. A. Daigre reported the North Island colony continuing seemingly to thrive with well over one thousand nests. The fragmentary subsequent nesting data, all from North Island, follow: 1958 thousands of adults along with young of all ages on June 7 (W. H. Turcotte and others); 1959 no report; 1960 approximately 200 pairs nesting on April 20 (J. Valentine, J. Walther) and 300+ birds on September 9 (S. A. Gauthreaux); 1961 100 nests on May 21 (Valentine) increasing to 150 by June 6 (Walther, Valentine, R. Andrews); 1962 6 adults and no nests on June6, 7, and 8 (L. E. Williams, S. G. Clawson).
Since 1962 no nesting of native stock is known to have occurred in the state. Thus the Chandeleur chain and associated islands, site of the first recorded "natural" colony in Louisiana in 1918, became 44 years later the sire of the last.
Meanwhile on annual Christmas Bird Counts the Brown Pelican had undergone an even more rapid decrease. The totals were as follows: 1956 2 at New Orleans, 90 in the Cameron area; 1957 0 at New Orleans, 19 in the Cameron area; 1958 none on any count, though New Orleans, Reserve, and Cameron all turned in reports. The species has never since reappeared on a Louisiana Christmas count. A few birds were still occasionally sighted at odd times of the year in coastal parishes in the early 1960s, but by the middle of the decade even these reports had ceased.
The troubles of the species were by no means confined to Louisiana. Across the continent, in California, ornithologists were noting little or no production of young in the Brown Pelican colonies there. They discovered that the birds were laying eggs so fragile that the thin shells broke when the parents attempted incubation. Furthermore, they identified the causative agency as a chemical one, the chlorinated hydrocarbons widely used as pesticides. When rains fall, the runoff flushes the poisons from the soil and carries them to brooks and rivulets. Thence the substances move successively into larger streams, into rivers, and finally into the sea itself. All along the way, small fish are ingesting the chemicals along with normal food. Larger fish eat the smaller fish and are in turn devoured by still larger fish. At each transfer the concentration of poison in tissues intensifies. By the time a fish is swallowed by a large fish-eating bird high in the food chain, such as a cormorant, eagle, or pelican, the dosage can be dangerous indeed. Death seldom, if ever, ensues immediately; but the intruding hydrocarbons cumulate unnoticed in the fatty tissues. In times of stress, such as when storms impose unaccustomed physical exertion or when food is hard to procure for other reasons, pelicans can be forced to draw on energy reserves loaded with chlorinated hydrocarbons and then may be literally poisoned by their own fat. At such times they are likely to die. If they survive, they seem to do so as birds unable to reproduce effectively.
Sometime in the late 1950s, die-offs of fish began to become an annual event in Louisiana along the Mississippi and Atchafalaya rivers. In 1960 at least 30 large fish kills were reported to authorities, and in 1963 an estimated five million fish died. An investigation resulted that was eventually to identify the lethal agent as endrin and to pinpoint its source as a chemical plant in Memphis that manufactures this pesticide. Discharges of poisonous waste into the river by this plant were halted in 1965. During the years when Louisiana pelicans were disappearing, no chemical analyses of their eggs or tissues were ever conducted, but the similar timing of the fish kills and of the decline of the birds would appear to be more than mere coincidence.
I do not know how long a Brown Pelican normally lives, but I would guess that a bird reaching adulthood has a life expectancy of at least several years. Therefore one would expect the species to remain in evidence for a fairly long time after the production of young ceased. In Louisiana it did not do so. Brown Pelicans were still nesting in 1961, three and one-half years after the last individual was seen on a Christmas Bird Count; and the scarcity of the species on the Louisiana coast was noted before a drop-off in the numbers of breeding birds on North Island was noted. A possible explanation is that the North Island population may have consisted in large part of pelicans that lived for most of the year around the Chandeleurs, Mississippi Sound, and points east. These birds may not have been as immediately and as heavily subjected to doses of poison as were the birds farther west, nearer the mouths of the Mississippi River. At any rate, the disappearance of our Brown Pelicans seems not to have been a prolonged process brought about primarily by reduced fertility or weak-shelled eggs. The swiftness of the population collapse points to a direct die-off of adults.
In 1968, the history of the species in the state entered a new phase. That summer 50 young Brown Pelicans were imported from southern Florida by the Louisiana Wild Life and Fisheries Commission. Half were sent to Grand Terre, half to Rockefeller Refuge. In autumn of that year 30 of the birds were turned loose as free fliers 15 at Grand Terre in September and a like number at Rockefeller Refuge in October. By the time of their release, the latter birds had become so habituated to pen feeding that they made little attempt to fish on their own and continued to depend upon handouts for subsistence. To force them to support themselves, the Rockefeller biologists eventually denied the pelicans access to free meals. By this time, winter had come. A sudden cold snap was more than the birds could take. All died. At Grand Terre, meanwhile, the free fliers could be seen out over Barataria Bay plunging for fish. And they thrived through the winter.
In 1969, another 50 Brown Pelicans from Florida were split between Rockefeller Refuge and Grand Terre. This time the Rockefeller birds were allowed to fly free as soon as they were able. They responded by quickly disappearing, never to be seen again, dead or alive. At this point efforts to restore the species to western Louisiana came to an end. At Grand Terre the new releases remained in evidence and augmented the introduced Barataria Bay population. There the importation of more pelicans from Florida continued on an annual basis.
However commendable, the effort to reintroduce the Brown Pelican into Louisiana seemed to me to have a dim future. I could see no assurance that the causes that wiped out the species in the state, whatever they might have been, were not still in operation. But suddenly in the spring of 1971, only 31 months after the first release, the introduced pelicans began nesting. The small colony was on a perilously low and narrow shell reef conveniently close to the Wild Life and Fisheries Commission Grand Terre installation, separated from it by only a mile or so of open water. In the 13 nests there, 20 eggs were laid and 11 young hatched. Seven survived to grow to adult size.
The Brown Pelicans of Barataria Bay nested again in 1972 and 1973 but on a more suitable expanse of shell several miles farther east, on another island. The young surviving to the flying stage in htese years numbered 17 and 24, respectively, but the totals represented an actual drop-off in production per number of eggs laid, since increasing numbers of adults were participating in the productive process.
Because chlorinated hydrocarbons are cumulative poison, building up in tissues progressively, one might anticipate that older adults would have a lesser capacity to reproduce than youngr ones. So the initial breeding successes of transplants may be due to their youth. On the other hand, environmental conditions in Louisiana have improved to the point that there are fewer parts per million of chlorinated hydrocarbons in Barataria Bay than in the waters around the Florida rookeries whence our imports came. And eggshell thickness here, though somewhat subnormal, is appreciably better than in Florida and much better than in California.
At present, chemical contamination is probably doing less to impair reproduction than a combination of other factors. The introduced pelicans have brought with them the annual rhythm that governed their ancestors' activity in Florida. They begin to lay eggs in midwinter, a timing suitable in their native state but not in our climate. So the storms and low temperatures of late winter cause abnormal nesting mortality, aggravated by the fact that the birds are nesting on the ground, as I once found the pelicans doing on East Timbalier Island, rather than in low mangrove bushes, as they usually did on North Island. Be that as it may, limited nesting success and continued importation have increased the population in the Barataria Bay area to an estimated 400 birds. In the summer of 1973, Brown Pelicans were observed in Louisiana as far east as the Chandeleurs and as far west as East Timbalier Island.
The Brown Pelican lays from one to three eggs, which are either whitish or dirty brown in color. The young on hatching are naked, homely looking creatures but soon become covered with white down feathers. The adults feed their offspring by swallowing fish and then regurgitating partially digested portions back into the pouch. The baby pelican sticks its bill and head into its parent's pouch for its meal. The young grow slowly, and usually it is midsummer before they have completely lost their natal down, replaced it with contour feathers, and acquired their flight feathers. The full-fledged young are mostly gray in color and quite unlike their parents in their breeding dress. The front and back of the long neck of the adults are a rich mahogany brown and the top of the head and the sides of the neck are white. A few elongated feathers on the nape constitute some semblance of a nuptial crest.
Pelicans feed entirely on fish, almost wholly of noncommercial varieties. Turning in a half roll, they plunge bill first into the water and virtually disappear from sight in the resulting splash. The great pouch scoops up the prey and in doing so naturally scoops up several quarts of water. But the bird throws its bill upward, and this contracts the pouch, squeezing the water out through the corners of the mouth. The fish is then swallowed in an awkward gulp.
Pelicans are indeed queer birds. Despite their many marvelous structural adaptations, they have lost all vocal powers. The only sound ever heard from a pelican is the hissing, snakelike noise that the young make when intruders come near their nest. I never fail to marvel at the almost unbelievable differences between a pelican and, let us say, a hummingbird, as they appear in the field. It is difficult to believe that two creatures so superficially diverse could have stemmed from a common ancestor, although we know from their internal similarities they did just that millions of years ago. --George H. Lowery, Jr., 1974, Louisiana Birds

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