|No. 55||New Orleans, Louisiana||15 August 1970|
|Chicot Trip Nets 101 Species||New Members|
|Radiotelemetry Studies of Thrush Migration||Book Review|
|The Demise of the Brown Pelican in Louisiana||Current Literature|
|A Yellow-nosed Albatross in Louisiana|
|Cameron Spring Meeting|
|The Spring Meeting of the L.O.S. was held at Fred's Restaurant in Cameron on Saturday evening, April 25, with 54 members attending. Following a brief business meeting conducted by the President, Dr. Dan Purrington, Horace Jeter compiled the bird list for the day, which totaled 183 species. Mrs. Maxime Davis and Mr. Joe Kenndey were awarded signed bird prints for most nearly guessing Saturday's total correctly. In addition to this very respectable total, especially in the face of rather too pleasant weather, the meeting yielded several noteworthy species, in particular a Black-legged Kittiwake at Holly Beach found by Bob Hamilton and seen by most parties, a Kiskadee Flycatcher seen by Joe Kennedy at Hackberry, and a Black-whiskered Vireo found on Sunday behind the Cameron Courthouse by Dan Purrington which was photographed. The Fall Meeting was scheduled for Dec. 4-6, 1970 at Cameron.|
The program was an enthusiastically received illustrated talk by Dr. Donald Bradburn. Dr. Bradburn showed superb slides of the Atchafalaya Basin and the barrier islands off the Louisiana and Mississippi coasts, emphasizing the beauty and solitude of Horn Island, Miss. There were transparencies of birds, of course, notably the nesting ospreys of Horn Is., some of the insular flora was illustrated, and the fine presentation was strikingly concluded with a sequence of sunsets as seen from Horn Island.
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|CHICOT TRIP NETS 101 SPECIES|
|Rain and overcast skies, plus plenty of mud did not completely dampen the enthusiasm of the hardy birders who attended the Chicot Park Meeting on April 10-12. On Saturday they tallied 95 species and added six new ones the following day. There were 30 adults and 8 children present, the youngest being Christopher Purrington, aged 7 months. Friday evening's program consisted of two color films, "The Great White Pelican" and a part of Walt Disney's "White Wilderness." The White Pelican film, incidentally, may be obtained through the public library by local bird groups. Saturday evening a chili supper was held in the lodge, after which Mike Mushemeche compiled the bird list, and Mrs. Grace Eyster reviewed the book The Psychology of Birds. On Sunday the weather cleared, boating was popular, and Kenneth Eyster (age 13) caught a male Prothonotary Warbler in a butterfly net and displayed it for a while for all to see.|
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|RADIOTELEMETRY STUDIES OF THRUSH MIGRATION FROM LOUISIANA*|
|Although a number of techniques are available for studying the gross structure of bird migration, these techniques for the most part provide no information about individual birds and indeed give only a temporal view of what is happening at a single place on the earth's surface. Thus while radar and lunar observation can yield data on the density, height, and direction of migration, and something about the timing of migratory flights, these methods are incapable of providing direct information about the length of flight taken by individual birds, the fraction of time devoted by an individual bird to flying, vs. that given to resting and feeding, the variation in migration patterns in different individuals and as a function of species composition, etc.|
Radiotelemetry studies, in which birds are tagged with miniature radio transmitters provide a relatively new means of making detailed observations of the migratory flight of single birds. A study of this sort by researchers at the University of Illinois and the Illinois Natural History Survey has been under way for several years, led by Cochran and Graber.1 Spring 1970 brought some of the scientists involved in the study to Southeastern Louisiana in an attempt to follow migrating thrushes in their northward flights.
Although the experiments were not entirely successful, three thrushes were netted and radio-tagged at Delta Refuge. A tagged Veery captured on April 21, departed at 19:45 CDT the same day, and was tracked by car to Bay St. Louis, where it was lost. A Swainson's Thrush taqqed on April 25 departed on April 27 at 21:55 CDT, but headed toward Grand Isle (WSW) and was lost within an hour. The final bird, a Gray-cheeked Thrush, was captured on April 26, finally departed at 20:55 CDT on May 8, and landed about 10 miles north of Laurel, Miss. at 00:55 CDT May 9.
Obviously studies such as these, while still in their infancy, can provide a great deal of information about bird migration, particularly as the techniques become better developed and find more widespread use. While the transmitters used in this study were very light indeed, weighing only about 2 gms (compared to the body weight of a typical thrush of about 30 gms, the long antenna required may interfere enough with the activity of the bird as to influence its behavior. Thus as Cochrane, et al point out, the studies are not really of birds, but of radio-tagged birds. Nontheless, it is an exciting technique, which with future improvements, promises to provide data which are otherwise simply unobtainable.
* Most of the information given above was provided by Mr. Charles G. Kios of the Ill. Nat. History Survey.
1. W.W. Cochran, G.G. Montgomery, and R.R. Graber, The Living Bird, VI: 213-225 (1967). W.W. Cochran and C.G. Kios, Wilson Bull. (to be published).
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|THE DEMISE OF THE BROWN PELICAN IN LOUISIANA*|
| One of the most remarkable events in American ornithology was the complete disappearance of the Brown Pelican (Pelecanus occidentalis), during 1957-61, as a breeding bird along the central gulf coast of the United States. Especially remarkable is the fact that the decline of the species went almost unnoticed at the time.|
It was only in 1968, ten years after the fact, that the cause of the decline became finally clear -- organochlorine pesticide pollution. Other explanations advanced themselves at the time, inhibiting the sort of investigation that might have unearthed the real cause. These easy explanations, specifically the effects of tropical storms in 1956 and 1957, disease, human disturbance, and changes in food supply; along with the lack of observations of the breeding colonies, precluded studies of the reproductive failure which it is now clear was taking place and prevented an early understanding of the role of persistent chlorinated hydrocarbon pesticide (CHP) pollution of the terrestrial and aquatic environment.
Lest there be any doubt about the precise cause of the demise of the Brown Pelican, not only on the northern gulf coast, but more recently, on the Pacific coast, we shall examine in some detail the evidence bearing on the question.
Historically the Brown Pelican has bred at a number of sites in coastal Texas and in the vicinity of the Mississippi River delta in Louisiana. The most important Louisiana nesting colonies were on East Timbalier and North Islands, and on the mud lumps at the mouth of Pass a Loutre. The North Island colony is of particular importance in the present context since it has been the most closely studied. As many as 3000 pelicans were recorded there at one time, and even as late as the summer of 1958 "thousands, with young" were reported. By 1960 and 1961the number had declined to 150 - 200 nests, and in the latter year apparently the last nesting of the Brown Pelican in Louisiana occurred. Only six adults and no nests were reported in June 1962. The table below documents the decline in the wintering population as shown in the Cameron-Sabine Christmas Count totals for 1950 - 60. It is evident that between the winters of 1956 - 57 and 1957- 58 a precipitous decline occurred, and although the North Is. colony was active in the summer of 1958, breeding success must have been almost nil.
The peninsular Florida population seems to have remained relatively stable during this period, showing only a long-term decline in the face of the activities of man. This would appear to be due to the fact that Florida has few rivers which drain a substantial amount of agricultural acreage. Until recently it was thought that the Brown Pelicans of California and Baja California were escaping the fate which befell their gulf coast relatives; it is now clear that the species has experienced total reproductive failure in California, masked, as on the gulf coast, by the fact that the Brown Pelican is a long-lived (on the order of 10 years) and wide-ranging species.
|The mushrooming use of organochlorine pesticides in the 1950's and the coincidence in time with the imported fire ant program (in which great quantities of dieldrin and heptachlor were applied) with the disappearance of the Brown Pelican, coupled with the fact that the Mississipni River drains much of the agricultural land of the central U.S., suggested a causal relationship between pesticide use and extirpation of the pelican. Unfortunately almost no direct evidence concerning the relationship between Brown Pelican reproductive success and mortality and pesticide levels in eggs and tissue exists for the no longer extant gulf coast population. What little evidence there is concerns eggshell thickness; this will be discussed below. On the other hand, there is now a considerable body of data on pesticide levels in Florida and California Brown Pelicans, and in the latter case, unequivocal evidence of the causal role of pesticides; and analyses of pesticide accumulation in pelicans introduced as juveniles in Louisiana. In addition there exists very strong evidence that organochlorine pesticides have caused dramatic reduction in the reproductive success of other species at the top of aquatic ecosystems, notably the Osprey, Bald Eagle, and Peregrine Falcon. These pesticides have also been indicted in the decline of the cahow, various species of cormorants, the Fulvous Tree Duck, the Prairie Falcon, White-faced Ibis, etc.|
Recent data comparing pesticide levels in Florida Brown Pelicans with those in pelicans introduced into coastal Louisiana from Florida shows that while the adult Florida birds show a much higher level of DDE (a DDT metabolite) and dieldrin than juvenile Louisiana birds, the latter show substantially higher levels than Florida pelicans of the same age. Although the significance of these levels is not precisely known, it may be instructive to examine some of the data on the levels of these fat-soluble pesticides in eggs of California Brown Pelicans taken from the colonies on Anacapa where nearly total reproductive failure has taken place. In the summer of 1968 only 31 of 637 nests contamed intact eggs and egg samples taken showed 68 ppm DDT as a fraction of total wet content and up to 522 ppm of the yolk lipid. On Los Cornados Is. 19 eggs were found in 300 nests. Even well to the south in Baja California 1212 nests yielded only 2618 eggs, nearly 30% below the expected average of 2.95 per nest. Eggs with little or no calcium carbonate were common in the California colonies. Anderson and Hickey recently found that egg samples taken at Anacapa in 1962 show a 26% decrease in shell thickness from pre-1949 levels. In South Carolina and Florida, where reproductive success apparently continues high, there has been a reduction in egg shell thickness by 7-18% since 1947.
At this point, while it is clear that chlorinated hydrocarbon pesticides are largely responsible for the decline in reproductive success of the Brown Pelican and other fish eating birds, and while there is experimental evidence of the effects of these pesticides on eggshell thickness, it is not entirely clear how they act physiologically. It is known, however, that DDE and dieldrin induce enzymes in birds which degrade steroids which in turn control eggshell formation. DDT has been found to inhibit carbonic anhydrase, an enzyme involved in calcium carbonate formation. Some of these effects have occurred at levels as low as 10 ppm DDT and 2 ppm dieldrin. In addition to these and other physiological effects, there is evidence that pathological behavior including egg destruction and nest desertion may result from effects of chlorinated hydrocarbon pesticides on the central nervous system.
In Louisiana, the decline of the Brown Pelican as a nesting bird after the 1958 breeding season was abrupt, although it is somewhat surprising that the dramatic drop in the wintering population occurred between the 1956 and 1957 Christmas Counts, as mentioned above. The first indication of something amiss, though no importance was attached to it at that time, may have come during the summer of 1956 when 50 dead pelicans were found on Isle au Pitre, others on the Chandeleurs, and 20 - 25 on Petit Bois Is. At the time this mortality was blamed on an early summer storm. Hurricane Audrey struck southwestern Louisiana on June 26, 1957 and for a while it was widely speculated that Audrey was somehow implicated in the disappearance of the Brown Pelican. It may in fact have been, as we shall see, though certainly not directly; gales at the worst, were experienced on North Island as a result of the storm. And, in any case, "thousands" were reported on the island the following summer.
The Brown Pelican has not been known to nest in Louisiana since 1961 and indeed it may be that since the summer of 1967 the species has been extinct in the state, except for birds introduced from Florida. These birds, released by the Louisiana Wildlife and Fisheries Commission at Rockefeller Refuge and Grand Terre Island, while not likely to form the basis for reestablishment of the species until the persistent pesticide pollution has been eliminated, should yield important direct information on the effects of DDT and other CHP on pelicans in coastal Louisiana. The only "direct" evidence now available comes from the oological study of Anderson and Hickey, in which it was found that post-1949 eggs collected in Texas showed a 20% decline in shell thickness, while those from Florida were down 17%.
It is known that the reproductive failure among California Brown Pelicans has been due to chlorinated hydrocarbon pesticide ingestion, specifically their effects on calcium metabolism, that birds introduced from Florida into Louisiana coastal waters have accumulated significant pesticide levels in a very short time, and in cases have apparently died as a result, and since the gulf coast population is known to have suffered a significant reduction in eggshell thickness in the 1950's, it seems clear that the demise of the Brown Pelican in Louisiana may be blamed directly on organochlorine pesticide pollution of the waters of the Gulf of Mexico and the coastal marshes. On the other hand, it may well be that the recurrent tropical storms of the gulf coast played a role. It is known that CHP accumulate in fatty tissue, along with that of the liver and brain, and that these tissues show much hiqher residues than other animal tissue. It has thus been suggested that during periods of stress, particularly when storms make feeding difficult or impossible for up to several days, that the metabolizing of subcutaneous fat may result in mortality or central nervous system damage. It may thus be that "Flossy" in September 1956 and "Audrey" in June 1957 contributed, albeit indirectly, to the disaster which befell the Brown Pelican. This is consistent with the suggestions that the mortality noted during June and July of 1956 was related to a June storm.
It is all well and good to understand why Louisiana no longer has the Brown Pelican, and to deplore the environmental pollution which is to blame. Such knowledge, on the other hand, if not put to use in stopping the use of hazardous (ecologically) pesticides, will be of little value, and we will be treated to the spectacle of nesting failure in cormorants, herons, laridae, etc. We are already losing the Peregrine Falcon, the Osprey, the Bald Eagle; west-coast cormorants are being affected--where will the list end?
by Donald Norman and Robert D. Purrington
* A fully documented version of this article is available.
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|A YELLOW-NOSED ALBATROSS IN LOUISIANA|
On May 9, 1970, what was perhaps the first albatross ever recorded in the Gulf of Mexico, and certainly the first for the northern gulf coast, was found by Joe Kennedy and Jim McDaniel near Holly Beach in Cameron Parish. The bird, which was a Yellow-nosed Albatross (Diomedea chlororhynchos), was photographed by both observers at distances as close as 75 yards. The excellent color transparencies were shown to Robert Cushman Murphy and to George Watson, who confirmed the indentification. It goes without saying that the bird is a new addition to the Louisiana list. Additional details will appear in a forthcoming issue of Audubon Field Notes and a full description is being prepared for publication in The Auk.
THE "600" CLUB
The L.O.S. has received a message from Mr. Earle R. Greene, who is known to many long-time members of the organization, and who is a charter member of L.O.S., concerning The "600" Club. Mr. Greene furnished an Offical Summary of the membership of the club, and requested that any prospective members, i.e. individuals who have duly recorded 600 or more species of birds within the area of the fifth edition of the A.O.U. Checklist, submit the exact number of species recorded to him by October 1, 1970. As of April 15, 1970, the club had 47 living members, California dominating the list with 14 members. The LOS has at least four "600" Club members, with Laurie Binford's (now of California) 616 topping the list. Jerry and Nancy Strickling, formerly of Houston and now living in St. Louis, had 602 and 600 respectively. Louisiana's only member is Horace Jeter who squeaked in (no pun intended) with 603 species. The man who, according to the list, has seen more North American species than any other individual is Mr. Joseph W. Taylor of New York, with 676 species, while names like Gabrielson, Peterson, Keith, Small, Cruickshank, and Pough are sprinkled throughout the list.
Mr. Greene's address is 1600 West Fifth Street, Oxnard California 93030.
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The Purple Martin: A Complete and Authentic Guide to One of America's Favorite Birds, R.B. Layton, Nature Books Publishers, P.O. Box 12157, Jackson, Miss.
The great demand for information about the Purple Martin and martin houses should make this 192-page paperback popular, and its modest price, $2.98, should deter no one. In addition to the customary details of martin house construction, the book summarizes most of the published information on the life history of the species. Although all or most martins have now left nesting boxes for their communal roosts, it is none too early to be thinking about next year's nesting season, if new houses are to be built. But whether one is interested in how, when, and where, as regards martin house construction, or is simply interested in reading about one of our most attractive and sociable birds, this volume should be welcome.
by Robert D. Purrington
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The first known nesting of the Magnificent Frigatebird in the United States was recorded during the summer of 1969 at Marquesas Keys, Fla., with 54 nestlings counted in March. This has particular relevance to observers in Louisiana, in view of the large Frigatebird colony on North Island. Indeed, there was in the summer of 1969 an unconfirmed report of one or more frigatebird nests on North Island. The report was dismissed as most improbable, and only a cursory search was made as a result of the report. Aud. Field Notes 23:652 (1969).
BEHAVIOR AND BREEDING BIOLOGY OF THE RED-COCKADED WOODPECKER, J. David Ligon -- Red-cockaded Woodpeckers excavate cavities in living pines infected with the fungal disease red heart (Fomus pini). Often this is a disease of mature and over-mature trees, but it may attack young pines. Eggs were laid from late April to early June, and the incubation period was found to be about 10 days. From 6 nests, 50% fledged, a rather low figure, with no more than two survivors per nest, the latter apparently a consequence of asynchronous hatching. The Red-cockaded Woodpecker was found to be very sedentary. Only the intelligent use of fire will maintain the open pinelands necesaary to this species, and if careful management of pine forests in the south leads to removal of diseased trees, the bird will most likely be eliminated. Auk 87:255-278 (1970).
TEMPERATURE CHANGES IN CHIMNEY SWIFTS AT LOWERED ENVIRONMENTAL TEMPERATURES,J.J. Ramsey --To confirm reports of torpor in the Chimney Swift, birds were exposed to lowered ambient temperatures; in the range l0.70C to 41.00C the body temperature was found to be proportional to the environmental temperature. Eventually, as the temperature was lowered, torpidity occurred, with no movement or response to stimuli. After a few minutes at room temperature, the birds began to breathe slowly and eventually returned to a lively condition. Condor 72:225-229 (1970).
A POPULATION ESTIMATE OF THE DUSKY SEASIDE SPARROW, Brian Sharp --The Dusky Seaside Sparrow, which is confined solely to the vicinity of Merritt Island, Fla., has recently been the cause of some concern indeed is now on the list of rare and endangered species. Since the Merritt Is. salt marsh was impounded in 1957 for mosquito control, the number of pairs of the sparrows has dropped steadily, the number being about 70 pairs in 1961-63. This study disclosed only 33-34 males on Merritt Island, but uncovered a heretofore unknown colony of about 640 males (372 counted) in the St. John's River marsh. The total number of males of the species was estimated at 894. While this figure is encouraging, the stringent habitat requirements of the species make its survival in the face of rapid development of this part of Florida doubtful. Wilson Bull. 82:158-166 (1970).
AN INTERGENERIC HYBRID FLYCATCHER (Tyrannus x Muscivora), L.I. Davis and F.S. Webster -- A presumed hybrid of the Western Kingbird and Scissor-tailed Flycatcher was carefully observed in Austin, Texas in 1967. Detailed studies of the plumage of the bird and comparison of sound spectra with those of the supposed parent species prompted this conclusion. The hybrid nested with a Western Kingbird, but the nest was ultimately abandoned. Condor 72:37-42 (1970).
BIOLOGY OF THE IMMIGRANT CATTLE EGRET (Ardeola Ibis) IN GUYANA, SOUTH AMERICA, Rosemary H. Lowe-McConnell --The phenomenal nesting success of the Cattle Egret was found to be due substantially to the breeding biology of the species, althouqh ecological changes wrought by man and selective shooting were also found to be important. The Cattle Egret in Guyana has two nesting periods per year, giving it a natural advantage over its rivals which raise only a single brood yearly. It was also found to react faster to the onset of the rainy season and thus to get the best nest sites. The Ibis 109:168-179 (1967).
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Miss Joanna Burger, a graduate student at the Museum of Natural History of the University of Minnesota, in the course of a study of Franklin's Gull migration, has color-marked 300 immature birds with wing bands. The bands are about 1 1/2 in. in diameter and are orange, blue, purple, and black in color. If any of these birds are sighted, the date, location, and color of band should be noted. Miss Burger would also like to know the numbers of adults and immatures comprising the flock.
The Secretary-Treasurer, Mrs. Grace Eyster, would again like to suggest that members consider paying their dues for two or three, or even five years, to save the time, trouble, and expense associated with appealinq for and processing the $l.00 dues payment. And, of course, the member benefits as well. Mrs. Eyster would also like to remind members who are moving or who have moved to inform her of the change of address.
The 1970 membership list will be prepared in the near future, so it behoves each member in arrears to pay his soon as possible.
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NEW LIFE MEMBERS!|
It is with great pleasure that we welcome three new LIFE MEMBERS:
Dr. Laurence C. Binford
Mr. John Fiske
Dr. L. P. 0'Meallie
While all are long-time L.O.S. members, the support and encouragement provided by their becoming LIFE MEMBERS is considerable.
|WELCOME NEW MEMBERS!
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