Survival of Slender-billed Gull chicks during the crèching period

Capsule Crèches formed early in the season lasted longer than those formed later, but a longer crèching period did not appear to confer higher chick survival.

Aims To investigate the ecological factors influencing the benefit to parents of crèching behaviour by measuring chick survival.

Methods Mark–recapture was used to model apparent daily survival of 505 chicks during the crèching period in three different crèches. We contrasted models with different tipping points to assess possible differences across crèches in chick survival during the first week and in the moment at which chick departures began.

Results We did not find a clear difference across crèches on daily chick survival during the first stages of the crèche. By modelling chick apparent survival as a linear function of time we showed that the latest formed crèche dispersed more rapidly.

Conclusions The two crèches formed early in the season lasted longer than the one formed later but chicks did not appear to have a higher survival over the first week of crèching. We suggest that a longer period at the crèche should result in a higher survival in the period soon after fledging because chicks leave the crèche 4–7 days older than other chicks. Furthermore, early crèches are synchronous with those of other species breeding in the same area, thus perhaps diluting predation. We discuss the limitations of our analysis and the possible implications for the community of waterbirds breeding at our study site.     

Census of Black-headed Gull colonies in Scotland, 1958

ROOK POPULATION OF DERBYSHIRE, by A. Dobbs

WEEK-END BIAS IN RARITY RECORDS AT LOCALITIES WITH DAILY COVER, by R. E. Scott     

Reports and Other Items

Annual Report of The Edward Grey Institute, by David Lack

Origins and Progress of the Census of Heronries, by E. M. Nicholson

Nest Record Scheme, by J. F. Burton

The Bird Observatories in 1953, by E. A. R. Ennion     

Opportunistic feeding responses of the Yellow-legged Gull Larus michahellis to accessibility of refuse dumps

Capsule The gulls adjust their diet composition and diversity according to refuse dump accessibility.

Aims To examine the influence of the accessibility of open-air refuse dumps on the pre-laying diet of the adult Yellow-legged Gull.

Methods We studied six colonies settled on six rocky islands off the southeastern coast of France. A comparative study of the diet of breeding adults from the six colonies was made through pellet analysis (a total of 848 pellets). We determined the main foraging habitat used (refuse dumps, terrestrial habitats, marine habitat) and the number of foraging habitats used simultaneously (one, two or three), from which we deduced the mean diet diversity.

Results Refuse dumps were consistently the main foraging habitat (evidence in 53–74% of pellets) for the six colonies, even when refuse dump accessibility was low. The majority of pellets contained materials from two simultaneous foraging habitats (evidence in 50–64% of pellets). We demonstrated the influence of a gradient of refuse dump accessibility in terms of adjustment of the pre-laying adult's diet. Indeed, high refuse dump accessibility leads to a poorly diversified diet dominated by refuse. In contrast, when refuse dump accessibility is low, Yellow-legged Gulls broaden their trophic niche, with an increased exploitation of alternative foraging habitats, such as terrestrial habitats.

Conclusion These results show the species' opportunistic feeding and high adaptability, two parameters which need to be known to foresee the consequences on population dynamics, feeding and predatory behaviour of a sudden and severe food shortage, for example due to closure of open-air refuse dumps.     

Reports And Other Items

Summary Report On Nesting Tits, by David Lack

The Ringing Scheme 1954, by Robert Spencer     

Apparent survival rates of a long-lived partial migrant: the Yellow-legged Gull Larus michahellis

Capsule: In Yellow-legged Gull Larus michahellis populations from the eastern Adriatic Sea, there are considerable differences in the ratio of migratory birds and apparent survival among the colonies. Survival was dependent on age, colony and area of dispersal.

Aims: To identify the ratio of migratory birds within populations of Yellow-legged Gulls, and to compare apparent survival of gulls during migration in central and northern Europe and around the Adriatic Sea.

Methods: We analysed 15 years of resighting data of Yellow-legged Gulls using a MARK multi-state model to calculate survival rates. The effects of age, natal colony and area of dispersal were examined.

Results: Almost 60% of Adriatic Yellow-legged Gulls were migratory but the ratio varied among colonies (10.3–78.3%). Survival was dependent on age, colony and area of dispersal, with average values per group ranging between 0.599 (se 0.093) and 0.684 (se 0.084).

Conclusion: The ratio of migratory and dispersive Yellow-legged Gulls from different Adriatic colonies might be affected by both inheritance and food availability.     

Indexing winter gull numbers in Great Britain using data from the 1953 to 2004 Winter Gull Roost Surveys

Capsule Winter Gull Roost Survey data spanning 50 years were used to generate population indices.

Aims To evaluate how wintering numbers of five gull species have changed in Great Britain over the last five decades.

Methods Generalized linear models were used to relate gull numbers to habitat, site and year factors, and so derive species‐specific indices for nine regions of Great Britain. Regional models considered data from different timescales depending on coverage.

Results Patterns of change varied by species and region. All species showed increases in number over the period 1953 to 2004. In most regions, Black‐headed Gull Chroicocephalus ridibundus numbers have declined since peaks between 1973 and 1993; Common Gulls Larus canus have also declined recently in some regions. Lesser Black‐backed Gull L. fuscus numbers have increased dramatically since 1953, whereas numbers of Herring Gull L. argentatus showed large declines between 1963 and 1983. Great Black‐backed Gull L. marinus numbers have increased in the west and the Midlands, but recently declined in eastern regions.

Conclusions Numbers of wintering gulls in Great Britain have shown rapid changes over the last five decades, reflecting changes in the sizes of breeding populations. These changes are likely to be associated with changes in human activities and resource availability.     

Heredity counseling

THE RISE AND FALL OF T. D. LYSENKO: By Zhores A. Medvedev. Translated by I. Michael Lerner. Columbia University Press, New York, 1969. 284 pp. $10.00.

TOO MANY: A STUDY OF EARTH'S BIOLOGICAL LIMITATIONS: By Georg Borgstrom. Macmillan &; Co., Ltd., London, 1969. 368 pp. $7.95.

POPULATION (Second edition): By William Petersen. The Macmillan Co., New York, 1969. 735 pp. $10.95.

THE INTELLECTUAL MIGRATION: EUROPE AND AMERICA, 1930–1960: Edited by Donald Fleming and Bernard Bailyn. Belknap Press of Harvard University Press, Cambridge, Massachusetts, 1969. 748 pp. $12.95.

CELL STRUCTURE AND ITS INTERPRETATION: Edited by M. McGee‐Russell and K. F. A. Ross. St. Martin's Press, New York, 1969. 433 pp. $25.00.

AN ATLAS OF MAMMALIAN CHROMOSOMES: By T. C. Hsu and Kurt Benirschke. Springer‐Verlag, New York. Volume 1, 1967, 200 pp., $9.40. Volume 2, 1968, 200 pp., $9.40. Volume 3, 1969, 200 pp., §9.40.

PRENATAL DETERMINANTS OF BEHAVIOUR: By J. M. Joffe. Pergamon Press, New York, 1969. 366 pp. $13.00.

DEVELOPMENTS IN FERTILITY CONTROL: Report of WHO Scientific Group. World Health Organization Technical Report Series, No. 424. Geneva, Switzerland, 1969. 36 pp. Price: $1.00.

BIOCHEMISTRY OF MENTAL DISORDERS: World Health Organization Technical Report Series No. 427. Geneva, Switzerland, 1969. 48 pp. $1.00.

ATLAS OF MENTAL RETARDATION SYNDROMES: By Sydney S. Gellis and Murray Feingold. Government Printing Office, Washington, D.C., 1968. $5.50.

THE GHOST IN THE MACHINE: By Arthur Koestler. Macmillan Company, New York, 1968. 384 pp. $6.95.     

Sex differences in growth rates of Yellow-legged Gull Larus michahellis chicks

Capsule: Chick growth rates was sex-dependent in an Atlantic Yellow-legged Gull Larus michahellis population.

Aims: To describe the growth rate of Yellow-legged Gull chicks and sex-associated variations, and obtain a discriminant function to sex them using morphological data.

Methods: Fifty-two Yellow-legged Gull chicks from a colony in northern Iberia were measured for body mass, head and bill length, tarsus length and three other bill-length associated variables, from the hatching date up to the age of 36 days. Birds were sexed using DNA analysis.

Results: Using logistic models, chick growth rates was observed to be similar between the sexes, while the asymptote was higher among males for the majority of the variables. Discriminant analyses showed that the variable head+bill was very reliable to predict the sex of >80% of chicks at an early developmental stage, and 100% of chicks if combined with tarsus length and two more bill-length associated variables at the age of 35 days.

Conclusions: This is the first study using a discriminant analysis to sex Yellow-legged Gull chicks, and also the first to describe the growth function for the species. The growth rate varied between sexes because males showed higher asymptote values within the growth function.     

Trophic strategies of Yellow-legged Gull Larus michahellis on oceanic islands surrounded by deep waters

Capsule: The diet of Yellow-legged Gulls Larus michahellis on an oceanic island, surrounded by deep waters without a wide shelf, was mainly composed of terrestrial invertebrates.

Aims: To study the trophic ecology of Yellow-legged Gulls on an island surrounded by deep waters, to quantify the importance of terrestrial prey items and their availability, and to evaluate the relative importance of nutritional values of terrestrial and marine resources.

Methods: Diet was monitored for one year. We assessed the relative contribution of the main prey items and their macronutrients through the study of pellets and faeces.

Results: Terrestrial invertebrates were the most frequently consumed prey items (frequency of occurrence (FO) 67%), followed by marine fish (Osteichthyes FO 33%). Coleoptera and Orthoptera were the most consumed terrestrial invertebrates and provided a high nutritional value. The rate of consumption of terrestrial invertebrates varied in synchrony with the breeding season, being higher in spring, indicating their potential importance for reproduction.

Conclusion: It is unusual that terrestrial invertebrates constitute a large proportion of the diet of large gulls, but they seemed to cover their trophic energy requirements during the reproductive period.     

Guides to the Freshwater Invertebrates of Southern Africa. Volume 6: Arachnida and Mollusca

June 2002, Water Research Commission, Pretoria, South Africa

Ring-bound, soft cover, 141 pages

WRC Report No. TT 182/02; ISBN 978–1-86845875–2; price R100.00 (South Africa), US$50.00 (International)

Obtainable from the Water Research Commission, Private Bag X03, Gezina, Pretoria 0031, South Africa. or orders@wrc.org.za     

Abstracts

BIOFEEDBACK AND SELF‐CONTROL, 1970. Edited by Theodore Barber, Leo V. Di‐Cara, Joe Kamiya, Neal E. Miller, David Shapiro, and Johann Stoyva. Aldine Press, Chicago, 1971. 546 pp. $12.00.

INSANITY AND IDIOCY IN MASSACHUSETTS. REPORT OF THE COMMISSION ON LUNACY, 1855: By Edward Jarvis. Harvard University Press, Cambridge, Mass., 1971. 213 pp. $9.00.

METRIC TRENDS IN HOMINID DENTAL EVOLUTION: By Milford H. Wolpoff. Studies in Anthropology No. 2, Case Western Reserve University Press, Cleveland, 1971. 244 pp. $5.95.

CULTURE AND POPULATION: A COLLECTION OF CURRENT STUDIES: Edited by Steven Polgar. Carolina Population Center, Chapel Hill, North Carolina, 1971. 19S pp. $1.50, paperback.

AN INTRODUCTION TO ANTHROPOLOGY: By Ralph L. Beals and Harry Hoijer. Fourth Edition. The Macmillan Company, New York, 1971. 711 pp. $10.95.

CARMICHAEL'S MANUAL OF CHILD PSYCHOLOGY. Edited by Paul H. Mussen. John Wiley and Sons, Inc., New York, 1970. Two vols: Vol. 1, 1519 pp., $30.00; Vol. 2, 782 pp., $20.00. The set: $40.00.

MATHEMATICAL TOPICS IN POPULATION GENETICS: Edited by Ken‐ichi Kojima. Springer‐Verlag. New York, 1970. 400 pp. $18.70.

AMERICAN DAWN. A NEW MODEL OF AMERICAN PREHISTORY: By Louis A. Brennan. MacMillan, New York, 1970. 390 pp. $8.95.

PROGRESS IN MEDICAL GENETICS: Edited by Arthur G. Steinberg and Alexander G. Bearn. Vol. 7. Grune and Stratton, New York, 1970. 243 pp. $16.50.

CONGENITAL MALFORMATIONS: Edited by F. Clarke Fraser and V. A. McKusick. Excerpta Medica, Amsterdam, New York, 1970. 450 pp. $27.00.

THE HUMAN PLACENTA: By J. D. Boyd and W. J. Hamilton, W. Heffer and Sons Ltd., Cambridge, 1970. 365 pp. $43.83.

DENTAL HEALTH EDUCATION: Report of a WHO Expert Committee. World Health Organization Technical Report Series No. 449, World Health Organization, Geneva, 1970. 28 pp. $0.60.

MULTIPURPOSE SEROLOGICAL SURVEYS AND WHO SERUM REFERENCE BANKS: Report of a WHO Scientific Group. World Health Organization Technical Report Series No. 454. World Health Organization, Geneva, 1970. $1.75. 95 pp.

MENTAL HEALTH OF ADOLESCENTS AND YOUNG PERSONS. REPORT ON A TECHNICAL CONFERENCE: By A. R. May, J. H. Kahn, and B. Cronholm. World Health Organization, Geneva, 1971. 72 pp. $1.75.

BIOLOGICAL RESEARCH IN SCHIZOPHRENIA: Report of a WHO Scientific Group. World Health Organization, Geneva, 1970. 35 pp. $1.00.

EVOLUTION BY GENE DUPLICATION: By Susumu Ohno. Springer‐Verlag, New York‐Heidelberg‐Berlin, 1970. 160 pp. Hard cover, $9.90.

SYMBIOSIS. ORGANISMS LIVING TOGETHER: By Thomas C. Cheng. Pegasus, New York, 1970. 250 pp. $6.95 ($2.25, paperback).

MARIHUANA RECONSIDERED: By Lester Grinspoon. Harvard University Press, Cambridge, Mass. 1971. 443 pp. $9.95.

THE KHANNA STUDY: POPULATION PROBLEMS IN THE RURAL PUNJAB: By John B. Wyon and John E. Gordon. Harvard University Press, Cambridge, 1971. 437 pp. $14.00.     

Pre-fledging survival in a Yellow-legged Gull Larus michahellis population in northern Iberia is mostly determined by hatching date

Capsule: Pre-fledging survival in a Yellow-legged Gull Larus michahellis population in northern Iberia is negatively correlated to hatching date.

Aims: To explore which factors have more importance in determining the pre-fledging daily survival rates in a Yellow-legged Gull population from northern Iberia. Specifically, we tested for the effect of hatching date and order, body size and condition and meteorological conditions on pre-fledging survival.

Methods: Cormack–Jolly–Seber models with mixtures were used to model daily survival rates.

Results: Daily survival rates were mostly negatively affected by hatching date.

Conclusions: Hatching date was the most important factor affecting survival of chicks during the pre-fledging period in a Yellow-legged Gull colony from northern Iberia.     

Egg shell removal by the Black-headed Gull (Larus r. ridibundus L.) II. The effects of experience on the response to colour

WESTWARD VAGRANCY OF SIBERIAN PASSERINES, by C. W. Holt and Kevin Baker

BREEDING BIOLOGY OF THE WHINCHAT, by R. F. Ruttledge and David Scott     

Breeding distribution,population size and conservation of the Greyheaded Gull Larus cirrocephalus in southern Africa

Brooke, R.K., Allan, D.G., Cooper, J., Cyrus, D.P., Dean, W.R.J., Dyer, B.M., Martin, A.P. & Taylor, R.H. 1999. Breeding distribution, population size and conservation of the Greyheaded Gull Larus cirrocephalus in southern Africa. Ostrich 70 (3&4): 157–163.

The Greyheaded Gull Larus cirrocephalus occurs throughout southern Africa, both coastally and inland, and has bred at one time or another at 67 known localities since the 1860s. Most of these sites have been occupied by small numbers of birds, even single pairs, and for only one or a few years. The two principal breeding areas are the East Rand in Gauteng and Lake St Lucia in KwaZulu-Natal, both in South Africa. The next most important sites are Walvis Bay, Namibia and Lake Ngami, Botswana. The total southern African breeding population is estimated as about 2000 pairs. The Greyheaded Gull is not a threatened species in southern Africa, with 27 breeding sites supporting more than half the breeding population within formally conserved areas.     

Studies on Gull Lake, Michigan

The seasonal and depth distribution of phytoplankton in Gull Lake, a moderately large, temperate, dimictic, recreational lake in southern Michigan, U.S.A., is described and discussed. Diatoms (Fragilaria crotonensis, Cyclotella michiganiana, Asterionella formosa, and Synechococcus) grow mainly in summer. Diatoms grew under the winter ice, and objections are lodged to the classic explanation of seasonal growth in temperate lakes, and to a recent hypothesis concerning the `paradox of the plankton'. Two raphe-bearing large diatom species were considered to be truly planktonic. A Synechococcus species was similar to that described previously only from Loch Leven.     

Academic performance in Hawaii

Abstract

Differences among census tracts in academic performance are estimated and related by path analysis to social class, race, and school characteristics in the only American state without local autonomous school districts. Contrary to the Coleman Report, school has a significant effect and race does not, but social class is the major cause of census tract difference in academic performance. Without appropriate data on family resemblance, a genetic component in class structure cannot be delineated.     

Buchbesprechungen

Abstract

“Tracing and treating mineral disorders in dairy cattle“. Herausgegeben vom Komitee für Mineral-stoffernährung Den Haag, erschienen bei Centre for Agricultural Publishing and Documentation Wageningen 1973. 61 Seiten, 10 Tabellen, Format: 19,4 × 13,4 cm, kartoniert, Preis: 8,50 Dfl. Reviewed by H. Bergner.

D. Giesecke und H. K. Henderickx: Biologie und Biochemie der mikrobiellen Verdauung. Erschienen in der BLV Verlagsgesellschaft München, Bern, Wien, 1973. 373 Seiten, 123 Abbildungen (Fotos, Zeichnungen) und über 100 Tabellen. Format: 17 ×24,4 cm, Leinen, Preis: 198,- DM. Reviewed by H. Bergner.

The Rowett Research Institute — Annual Report of Studies in Animal Nutrition and Allied Sciences. Vol. 29 1973, 146 Seiten, Broschur, Preis: 80 p. bzw. $ 2.00 (USA) Internationale Standard-Buch-Nr.: 0902297074. Reviewed by A. Püschner.