British Birds Research Articles

Flight Identification of European Raptors

Identification of birds of prey in flight will always be a problem. The best of us will never be able to feel completely confident about a group of species that shows such diversity of plumage, whose silhouettes vary in different circumstances and for which the challenge of identification is so often at considerable range. We four have been studying flight identification of raptors for at least seven years— mostly in Europe, but also in Asia and Africa. A chance meeting in autumn 1968 between B.P.N, and R.F.P. at the now legendary Camlica Hills of the Turkish Bosphorus brought the Danish and English teams together and it was agreed to co-operate in a series of papers covering all the European raptors. Shortly afterwards, the editors of British Birds asked us to consider publication in this journal and so the scheme was born. The series will be completed in eight parts:

Food of Nestling Crows in Northeast Scotland

Examination of the gizzard contents of nestling crows in Scotland shows that young birds receive a wider variety of foods than older ones. Interesting differences in diet appear as between Scottish farmland and English woodland birds.

Protozoan parasites of the blood of British wild birds and mammals*

The reported occurrence of protozoan parasites of the blood of British wild birds and mammals is reviewed. Nineteen species of British birds have been recorded as hosts of Haemoproteus (or Parahaemoproteus), Leucocytozoon (or Akiba), Plasmodium, Trypanosoma or “atoxoplasms” (a group whose taxonomic status is presently in doubt), and seventeen species of British mammals are known to be hosts of Babesia, Hepatozoon, Polychromophilus or Trypanosoma (including at least three species from Chiroptera: T. (Schizotrypanum) dionisii, T. (S.) vespertilionis and T. (Megatrypanum) incertum).

The Red-backed Shrike: A Vanishing British Species

Within the next decade the Red-backed Shrike may cease to exist as a British breeding bird. The picture painted by this latest survey of its status is a gloomy one. It would appear that the combined pressures of an adverse climatic trend, the fragmentation of its habitat in the name of ‘development’, and not least over-collecting of its eggs, have reduced the population to a dangerously low level.

Recoveries in Great Britain and Ireland of Birds Ringed Abroad

The recoveries presented in this list follow on from the combined report for 1969 and 1970 published in British Birds 64: 488–501.

THE CONTAMINATION OF BIRDS' FEATHERS BY FUNGI

SummaryFungi have regularly been recorded on feathers removed from birds. Cellulose‐decomposing spores which are merely carried on the feathers were common on birds sampled in Britain, but were fewer than expected on the basis of random distribution on birds sampled in India. Hyaline‐spored fungi were less common on Indian birds, and more abundant on British birds than expected. Keratinophilic fungi, which are related to the dermatophytes, were particularly associated with related groups of birds: thus Turdus spp. regularly yielded Arthroderma curreyi, and partridges were contaminated with Ctenomyces serratus. Chrysosporium spp. were widespread on birds in India and Britain. Where associations have been shown, feather fats from these birds stimulate, or do not depress the growth of the keratinophilic fungi. Otherwise, feather fats were inhibitory to the fungi. The temperature relationships of the fungi, showing no growth at 40°C, would explain the restriction of the keratinophilic fungi to the outer, contour feathers, and of dermatophytes mainly to the non‐insulated parts of the birds' surface.

Some Sharp-Tailed Grouse Population Statistics from South Dakota

A total of 5,680 sharp-tailed grouse (Pedioecetes phasinellus) were trapped, banded, and released on the Kadoka Area (2,100 square miles) and 1,605 on the Missouri River Area (750 square miles ) of South Dakota during the winters of 1963 through 1968. Winter population estimates of grouse on the Kadoka Area varied between 0.7 and 1.8 birds per square mile and between 0.9 and 1.8 per square mile on the Missouri River Area. The population estimate for the Missouri River Area was probably low due to low trapping effort on that area. A significant difference (P < 0.01) existed between juvenile: adult ratios of hunter-killed birds and those trapped during the initial month of trapping on both areas. A reduction in the juvenile: adult ratio of trapped birds on the Kadoka Area between December (3.50) and January-March (1.94) was significant (P < 0.01) as was that for the Missouri River Area between January (6.36) and February-March (2.68). These differences in age ratios probably reflected differential trap vulnerability of juveniles and adults early in the trapping periods. Annual mortality determined from recapture of marked birds was 71.5 and 70.4 percent for the Kadoka and Missouri River areas, respectively. Annual mortality based on returns of hunter-killed birds was 79.5 and 7().6 percent for the Kadoka and Missouri River areas, respectively. Hunters harvested a minimum of approximately 20 to 25 percent of the birds on the Missouri River and Kadoka areas each year. GROUSE IN SOUTH DAKOTA * Robel et al. 87 SNEDECOR, G. W. 1956. Statistical methods. 5th ed. Iowa State University Press, Ames, Iowa. 534pp. SUOMALAINEN, H., ANTD E. AeurMO. 1945. On the microbial decomposition of cellulose by wild gallinaceous birds (family Tetraonidae). Ornis Fennica 22 ( 1 ) : 21-23. TREICHLER, R., R. W. STONV, AND A. L. NELSON. 1946. Nutrient content of some winter foods of ruffed grouse. J. Wildl. Mgmt. 10(1 ): 12-17. WARD, G. M., AND F. B. JOHNSTON. 1962. Chemical methods of plant analysis. Canada Dept. Agr. Research Branch Publ. 1064. 59pp. WELLS, C. G., AND L. J. 1METZ. 1963. Variation in nuttient content of loblolly pine needles with season, age, soil, and position on the crown. Proc. Soil Sci. Soc. Am. 27 ( 1 ): 9093. WHITE, D. P. 1954. Variation in the nitrogen, phosphorus, and potassium contents of pine needles with season, crown position, and sample treatment. Proc. Soil Sci. Soc. Am. 18 ( 3 ): 326-330. ZWICKEL, F. C. 1966. Winter food habits of capercaillie in north-east Scotland. British Birds 59 ( 8 ): 325-336. Received for publication January 29, 1971. The sharp-tailed grouse is the most abundant upland game bird in western South Dakota. Data from intensive studies on movements, mortality, longevity, and other such basic information on populations are not available. Previous efforts (Baumgartner 1939, Aldous 1943, Janson 1950, Peterle 1A contributionfrom FederalAidProjectW-951956, Klett 1957, Ammann l957, Kobriger R-1 of the South Dakota Department of Game 196S) to obtain such data were only parFish and Parks, Pierre, and the Division of Biology (Contribution No. 1()98), Kansas Agricultural Extially successful, because those studies terperiment Station, Kansas State University, Manminated in 1 to 3 years, were conducted hattan. on remnant populations or involved small 2 Present address: Kansas State University Co. operative Extension Service, Manhattan. sample slzes. This content downloaded from 207.46.13.133 on Sat, 17 Dec 2016 05:23:40 UTC All use subject to http://about.jstor.org/terms 88 Journal of Wildlife Management, Vol. 36, No. 1, January 1972 In 1963, an intensive 5-year study of sharp-tailed grouse was initiated in South Dakota. Our paper presents some vital statistics of the population as revealed by trapping and hunter-kill data collected during the study. Scientfic names of the plants follow

Amendment: Changes Attributable to Pesticides in Egg Breakage Frequency and Eggshell Thickness in Some British Birds

Amendment: Changes Attributable to Pesticides in Egg Breakage Frequency and Eggshell Thickness in Some British Birds

British and European Birds in Colour, by Bertel Bruun and Arthur Singer. Hamlyn, 70s.

British and European Birds in Colour, by Bertel Bruun and Arthur Singer. Hamlyn, 70s.

Changes Attributable to Pesticides in Egg Breakage Frequency and Eggshell Thickness in Some British Birds

Before the late 1940s it was a rare event for broken eggs to be found in the nests of peregrine (Falco peregrinus) and sparrowhawk (Accipiter nisus), but from 1951 onwards, both species have shown a high frequency of clutch depletions in which eggs were either found broken, or disappeared in circumstances where human interference was not indicated as the cause. In most instances it appeared that the parent birds destroyed their own eggs, either by eating or by breaking and/or ejecting them (Ratcliffe 1958, 1960). Scottish golden eagles (Aquila chrysaetos) also showed an unusually high frequency of egg breakage, again attributable to parental destruction, during 1960-63 (Lockie & Ratcliffe 1964). Although golden eagle egg breakage evidently became frequent before 1960 (Ratcliffe 1960), lack of earlier observations made accurate dating of the change difficult. An examination of the eggshells of peregrine and sparrowhawk has recently disclosed that a highly significant decrease in weight (thickness) occurred in both during 1946-50, and has been maintained ever since; golden eagle eggshells showed a less marked but still highly significant decrease in weight (thickness), dating from around 1951 and continuing up to 1966 (Ratcliffe 1967a). The present paper sets out in greater detail the evidence for egg destruction and change in eggshell weight, and discusses the correlation between these phenomena; relationships to the well-established decline in population status and breeding success* in these three species are examined, together with the environmental changes believed to be responsible. The study has been extended to other raptors and a wider range of other bird types.

Bird Life

Book of British Birds Pp. 472. (Drive Publications: London. Published for the Reader's Digest Association, Ltd, and the Automobile Association, July 1969.) 75s.

British Birds. Volume 62

British Birds. Volume 62

The Shapes of Birds' Eggs: Mathematical Aspects

-In the Handbook of North American birds the description of egg sizes, and more particularly of egg shapes, proceeds o.n somewhat different lines from those of previous works. The present paper explains the methods of measuring and methods of reducing the observations. The elements actually measured are the conventional average length and breadth, plus the (unconventional) radii of the blunt and pointed ends. The standard deviations of each of these are estimated from the sample. From these measurements, all of which in effect are measurements of size, certain dimensionless quantities are derived hereinafter referred to as asymmetry, bicone, and elongation. These are specifications of shape independent of size. This paper sets forth the theory, modifies the theory to achieve maximum practical utility, and gives reasons for believing the results valid and adequate. In addition methods of sampling are discussed, and a new procedure of sampling is given for getting somewhat more representative results than heretofore. THE only figures usually given for the size of an egg are its length and its maximum diameter, hereinafter called its breadth. The older texts, such as the Catalog of eggs in the British Museum (1901) or Seebohm (1896), give the extreme values that have been encountered for these figures in some survey or other, and this specifies the range of lengths or breadths within which the dimensions of another egg of the same species may reasonably be expected to fall. In the Handbook of British Birds (Witherby et al., 1938), in Bent (1919), and in some other more recent texts the average value of length and breadth is given, together with the extreme values. Neither method is entirely satisfactory, for even if a hundred eggs were examined to obtain these extremes, it is obvious that if we examine another hundred, half the extremes may be exceeded. Still more recently, some authors have adopted the more useful procedure of giving the averages and the standard deviations rather than the average and the extreme values. Then, provided that the sample is drawn from a normal or Gaussian population of eggs-and Van Bree (1957) has shown that at least for the population he examined this assumption is sound-we can estimate the probability that an egg will depart by any given amount from the average. There is one precaution that has not normally been observed. Measurements should be strictly independent and on unbiased samples. As it has been shown (Preston and Preston, 1953) that parentage has a significant effect on egg size, a valid sample, if it is to represent a species, should have equal numbers of eggs from each parent, and indeed it would be best to have as many parents represented as possible. In the case of a human population, for example, it would not be wise, in estimating the average 454 The Auk, 85: 454-463. July, 1968 This content downloaded from 207.46.13.13 on Fri, 26 Aug 2016 06:15:40 UTC All use subject to http://about.jstor.org/terms July, 1968] Shapes of Birds' Eggs 455

Nematodes of the genus Capillaria zeder, 1800 from the collection of the London School of Hygiene and Tropical Medicine. II. Capillariids from British birds.

1. Ten species of Capillaria are recorded from eight species of British birds. C. blomei from the pheasant and partridge and C. exilis from the rook are new host records.2. The identity of C. reseda and the systematics of C. blotnei, C. bursata and C. caudinflata are discussed in the light of observations made upon material in the collection.

Migration-seasons of the Sylvia warblers at British Bird Observatories

Migration-seasons of the Sylvia warblers at British Bird Observatories

Recent Quantitative Work on British Bird Populations. A Review

Recent Quantitative Work on British Bird Populations. A Review

THE FOOD AND FEEDING HABITS OF TUFTED DUCK AYTHYA FULIGULA

Summary.The food and feeding habits of Tufted Duck Aythya fuligula are described, based on field observations and on the analyses of the stomach contents of 95 birds, all but one of them having fed inland; 57 were collected from a gravel pit near London, 28 from Northern Ireland and 9 from a number of English inland waters, in the shooting seasons 1959‐60 and 1960‐61.The London birds in both seasons had fed primarily on molluscs, mainly Dreissena polymorpha. The Northern Ireland birds, where D. polymorpha does not occur, had a more variable diet, again mainly molluscs, but with some crustaceans, insects and plant seeds. The English birds had a similarly variable diet with the emphasis on crustaceans (Asellus spp.) and with some molluscs, insects and plant seeds. Brief information is given on the food of young birds.It is suggested that the spread of D. polymorpha may be one of the factors explaining the recent spread of the Tufted Duck in certain areas. It appears that where one particular food such as D. polymorpha is not plentiful a more variable diet is taken, though molluscs always figure prominently. The type of food taken depends on the type of habitat used, the availability and size of the food items and on the methods of feeding.

THE MIGRATION OF EUROPEAN THRUSHES: A COMPARATIVE STUDY BASED ON RINGING RECOVERIES

THE MIGRATION OF EUROPEAN THRUSHES: A COMPARATIVE STUDY BASED ON RINGING RECOVERIES

A list of parasitic worms, including twenty-five new records, from British birds

A list of parasitic worms, including twenty-five new records, from British birds

Recent Observations on Helminthiasis in some British Game Birds

1. Helminth parasites may be important causes of disease and death among game birds, both among penned stock and in the field. S. trachea is probably the most important, but species of Heterakis follow closely, having both a direct and an indirect effect. T. tenuis must be considered as potentially important and may be responsible for much loss when the right ecological factors are present.2. It is clear that game farmers will need to pay careful attention to methods of controlling the spread of helminths: in particular, to prevent the spread of T. tenuis, which can build up quickly to epizootic proportions on restricted areas where the bird population is high. Pheasants are potential hosts of this species and the death rate could easily be serious under careless management.3. The presence of poultry near or with penned birds is fraught with danger as many helminths have a wide host distribution among related gallinaceous birds. Thus species of Capillaria and Heterakis which normally cause little trouble among poultry, can cause death and disease among game birds.4. The few wild chicks examined were interesting. There is a heavy loss of wild chicks but only rarely are dead ones seen so that little is known about the cause of this loss. Adverse weather conditions and predators no doubt are important, but it is obvious from the few cases reported above, that S. trachea and H. isolonche may also be causes of considerable importance.5. Many old birds are carriers of parasites and contaminate the ground with ova. Thus young stock with no resistance may well pick up lethal infestations, if they are allowed to graze land previously used by old birds.