The constraint on habitat use in wing-moulting Greylag Geese Anser anser caused by anti-predator displacements

During the flightless period of wing-moult, terrestrial feeding waterbirds tend to forage close to water. Wing-moulting Greylag Geese Anser anser feeding in a Danish saltmarsh were no exception to this pattern as none fed more than 175 m from the sea. An individual-based stochastic model of goose feeding distribution derived from empirical data showed that requirements for drinking water could not explain the coastal feeding distribution as the model predicted that 57% of all goose observations would be more than 175 m from the sea. The availability of Common Saltmarsh Grass Puccinellia maritima , the preferred food item, could partly explain the exploitation pattern of geese but not the absence of geese from inland feeding areas. Furthermore, the results did not support the hypothesis that geese actively avoided inland feeding areas because of elevated costs from vigilance. The frequency of anti-predator displacement to the sea was the most likely explanation of the feeding pattern. A model that included such displacements predicted that 99% of all geese would feed less than 175 m from the sea. As anti-predator displacement put the most severe constraints on the feeding distribution, predation risk and level of disturbance were suggested to be the overall factors, which determine the choice of moult site in wing-moulting geese.     

Within-pair testosterone covariation and reproductive output in Greylag Geese Anser anser

In monogamous animals, reproductive success may vary considerably among pairs. To study this variation, we focussed on reproductive events and the circannual hormonal co-ordination within pairs during the reproductive cycle. Testosterone was chosen as covariable for both sexes because of its mediator function between behaviour and physiology. In a flock of free-living Greylag Geese Anser anser , individual faecal samples were collected weekly from 23 pairs over a complete annual cycle. From the faeces, equivalents of testosterone, oestrogen and other steroid hormones were analysed by enzyme immunoassay. In contrast to correlations between male and female testosterone, no correlations were found between oestrogen-oestrogen or oestrogen-testosterone. Therefore, only testosterone (T) is considered here. Sex-specific differences in T were in amplitude rather than in the annual timing of maxima and minima. However, the annual timing varied to some degree between individuals within sexes. Therefore, we examined the degree of annual testosterone correlation (TC) within pairs. Pairs that nested had significantly higher TC over the year than pairs that did not. The higher the within-pair TC, the larger the clutches and the heavier the eggs. Also, TC in the year investigated was positively and significantly correlated with the pairs' long-term reproductive output. No correlation was found between TC and the duration of the pair-bond, individual age, or age difference from pair partner. We suggest that TC is a measure of behavioural synchrony and, therefore, pair-bond quality. We consider whether within-pair TC results from mate choice.     

A demographic comparison of two Nordic populations of Greylag Geese Anser anser

Greylag Geese Anser anser have been neck-banded on an annual basis in Scania, southern Sweden since 1984 and in Norway since 1986 as part of a Nordic Greylag project. This has yielded a large database of resightings, which we used here to estimate and compare survival rates between the two populations by means of mark–recapture models. Estimated adult survival was sex-dependent in the Scanian population, probably a result of differential neck band retention rates in this population. Mean juvenile survival was about 12% higher in the Scanian population (0.603 vs. 0.485). Adult survival in the Norwegian population was 0.728 (males 0.733; females 0.725), and in males and females from the Scanian population was 0.711 (0.752 after accounting for higher neck band loss in males) and 0.771, respectively. Over the course of the study, juvenile survival in the Scanian population increased substantially, and adult survival was constant, whereas both these parameters declined in the Norwegian population. This study demonstrates that the two Nordic populations are demographically distinct and gives further support to the notion that they should be treated as separate management units. The decline of 10% in adult survival in the Norwegian population, the cause of which still remains uncertain, is likely to have had a major impact on the growth of this population.     

Adjustments to nitrogen metabolism during wing moult in Greylag Geese, Anser anser

1. This study examined the nitrogen balance of free-living flightless moulting Greylag Geese, Anser anser , in relation to food quality, nitrogen absorption, food retention time and nitrogen excretion rates.
2. Food intake rates during moult were the same as those before and after the flightless period, but total daily time spent foraging fell by 58% from 9·45 h to 3·96 h. Dropping production during moult was 43%, and mean dropping mass 42% of that before and after moult, suggesting a considerable increase in food passage time through the gut during moult. Nitrogen absorption increased from 25% prior to moult to 47% during moult.
3. At the same time, excreted dry mass uric acid in faecal material fell by 68%, such that the proportion of nitrogen absorbed and retained in the body as a proportion of the nitrogen ingested in food rose from 16% prior to moult to 42% during moult.
4. Based on these significant increases in nitrogen absorption and decreases in nitrogen excretion, geese were able to compensate for reduced food intake and derive sufficient nitrogen from their diet to re-grow flight feathers.     

Nest site preference by Greylag Geese Anser anser in reedbeds of different harvest age

Maintenance of reedbeds and their associated avifauna requires intervention management to modify natural succession by means of, for example, reed cutting. Nest site density of Greylag Geese Anser anser in relation to time since reedbeds were last harvested was studied at Vejlerne nature reserve, Denmark (57°00–07'N, 8°50'–9°10'E). Low nest densities were found in areas in the first four years after cutting followed by high densities in areas unharvested for five or six years. Subsequently, nest density remained high for four to seven years (depending on site) before declining to low levels again. Areas cut in the year of study and areas cut more than 16 years before contained virtually no nests. The increase in nest density with time since last harvest seemed to be related to an increase in vegetation cover (reed stem density). Areas harvested more than 16 years before probably became too dense for the geese, and newly harvested areas had too low a shoot density, hence their low nest density. However, more detailed studies are needed to establish causal relationships.     

Declining winter survival and fitness implications associated with latitudinal distribution in Norwegian Greylag Geese Anser anser

The Norwegian Greylag Goose Anser anser population has been increasing steadily over the past few decades, causing increasing nuisance in terms of agricultural crop damage. This, in combination with the importance of Greylags as a hunting target, has called for demographic estimates for the population to assist in management decisions. To this end, we analysed long-term mark–recapture data using Cormack–Jolly-Seber models embedded in program MARK to obtain survival estimates for the population. No sex-specific difference, or age effect on survival after juveniles had completed their first migration (3 months of age), was evident. Mean first-year survival was reported as 0.485 and annual survival of older birds as 0.700. On a monthly basis, survival in Greylags during summer and winter was very similar over the study period. A significant linear decline in winter survival from 0.909 to 0.807 was, however, apparent during the study period. Over the second half of the study (1994–2002), summer survival was about 3% lower than in the first half (1986–94) but no linear relationship was evident. We found a significant inverse relationship between Greylag survival during summer and latitudinal distribution in Norway. A similar relationship was evident between survival and annual bag numbers. The changes in adult survival observed in this study are likely to have had a substantial impact on the growth rate of the Norwegian Greylag population.     

The function of flight formations in Greylag Geese Anser anser; energy saving or orientation?

Twenty five formations of Greylag Geese Anser anser were photographed from immediately below to eliminate perspective distortion, and the lateral and longitudinal displacements of the birds relative to each other were measured. We scaled the photographs and used measurements of bill to tail and wing span made on 15 freshly shot birds to convert the lateral displacements to wing-tip spacings. The birds flew on average with an overlap of their wing tips (median =17 cm) which corresponded very closely with the overlap expected (16 cm) from an aerodynamic model which predicted the position which maximized energy savings. However, the variation in positions was large, and only 17% of birds actually flew in the optimum range. The mean saving in induced power averaged across the distribution of positions was 26.5%, and the contribution to total flight costs was a reduction of 4.5–9%. This saving was greater than we found previously in the Pink-footed Goose Anser brachyrhynchus. There was no correlation between position in the skein and longitudinal displacement, as would be anticipated if the birds were equalizing the savings across the skein. This does not mean costs were not equalized because other mechanisms are possible. There was no correlation between depth and wing tip spacing which does not support the orientation/communication hypothesis. Body size and thus flight costs may be a factor influencing the function of formation flights.     

An approach to the assessment of change in the numbers of Canada Geese Branta canadensis and Greylag Geese Anser anser in southern Britain

Capsule Population change in geese was assessed using an approach that requires a relatively small sampling effort.

Aims During the 1999 breeding season a survey was carried out to determine if the numbers of introduced Canada and re-established Greylag Geese in southern Britain had changed since 1988–91 and whether any change had occurred in areas with previously high or low Canada Goose densities.

Methods A randomized stratified sample of 246 tetrads from the 24 156 tetrads covered between 1988–91 in this area, as part of the New Atlas of Breeding Birds, were resurveyed. Eight habitat categories were used in the stratification and were based on 1-km-square summary data obtained from the CEH Land Cover Map of Great Britain (water cover and urbanization) and LANDCLASS stratification (upland/lowland). The five habitat categories with the highest densities of Canada Geese and the greatest variance in numbers were sampled.

Results Between 1989 and 1999, the number of Canada Geese on land with over 5% water cover and on lowland with some water cover increased by on average 156%, an average rate of increase of 9.9% per annum. Southern Britain probably now holds a minimum of 82 000 Canada Geese. Between 1989 and 1999, the number of Greylag Geese on land with over 5% water cover and on lowland with some water cover increased by on average 214%, an average rate of increase of 12% per annum. Southern Britain probably now holds a minimum of 30 000 Greylag Geese.

Conclusion Maximum densities of Canada Geese may have been reached in high-density habitats but their numbers are still increasing very rapidly. Greylag Geese are increasing even more rapidly.     

Attempts on freezing the Greylag (Anser anser L.) gander semen

Semen of Greylag (Anser anser L.) ganders was frozen according to a method previously elaborated by the authors for freezing the White Koluda gander semen. Semen was collected from five to eight Greylag ganders, twice a week during three succeeding reproductive cycles, by dorso-abdominal massage. Semen samples were diluted in the ratio of 1:1 or 2:1 (two parts semen: one part diluent) with EK diluent, supplemented by 6% DMF, equilibrated and pre-frozen to -140 degrees C at a rate 60 degrees C/min, before being transferred into liquid nitrogen container. Semen samples thawed in a water bath of 60 degrees C were used for twice a week insemination in a volume of 200 microl. Three Greylag and three White Koluda geese were involved in frozen-thawed semen fertilizing ability test. The reproductive cycle of wild geese lasts usually about 6-7 weeks. The ejaculate volume (30-140 microl) and sperm concentration (10x10(6) to 150x10(6) ml(-1)) are much lower than these of domestic ganders, but spermatozoa morphology is similar, particularly while compared to 1-year-old White Koluda ganders semen. There are about 90% of live spermatozoa and about 30% of live morphologically normal cells in Greylag gander fresh semen. The Greylag gander spermatozoa susceptibility to cryopreservation procedure is as high as in domestic ganders. Dilution ratio 2:1 resulted in higher number of live spermatozoa, which withstood cryoinjury stress. In relation to fresh semen about 60% of spermatozoa remained intact (on the basis of light microscope examination) in the frozen-thawed semen. Insemination of frozen-thawed semen resulted in 37.5% of fertile eggs in Greylag and 25.0% in White Koluda geese. Low fertility rate was caused by an insufficient number of live normal spermatozoa used for insemination (about three million in every dose).     

Effects of Passive Social Support in Juvenile Greylag Geese (Anser anser): A Study from Fledging to Adulthood

In general, support by social allies may reduce stress, increase an individual's status and facilitate access to resources. In Greylag geese (Anser anser), offspring stay with their parents for an entire year or even longer and thereby enjoy social support in encounters with other flock members. We investigated the influence of spatial distance to one's allies on the outcome of agonistic encounters in a natural flock situation for a total of 12 sibling groups after fledging. In addition, we tested two groups of hand‐raised juvenile geese over a time span of 11/2 yr. Passive (i.e. not interfering) human supporters of different familiarity were placed at a standard distance during food provisionings, which produced a tight flock situation. Success in agonistic interactions increased with decreasing distance to members of their social unit. The hand‐raised juveniles were more successful in agonistic interactions and showed increased feeding rates when accompanied by a familiar human than when alone or with a non‐familiar human. The effect of the presence of familiar humans on success in agonistic encounters significantly decreased with increasing age, while feeding rates remained elevated. The positive effects of social support were particularly evident in females. We conclude that social support has similar effects and functions in the highly social greylag geese as reported for social mammals.     

Central European Greylag Geese Anser anser show a shortening of migration distance and earlier spring arrival over 60 years

Global climate change can cause pronounced changes in species? migratory behaviour. Numerous recent studies have demonstrated climate‐driven changes in migration distance and spring arrival date in waterbirds, but detailed studies based on long‐term records of individual recapture or re‐sighting events are scarce. Using re‐sighting data from 430 marked individuals spanning a 60‐year period (winters 1956/1957 to 2015/2016), we assessed patterns in migration distance and spring arrival date, wintering‐site fidelity and survival in the increasing central European breeding population of Greylag Geese Anser anser. We demonstrate a long‐term decrease in migration distance, changes in the wintering range caused by winter partial short‐stopping, and the earlier arrival of geese on their breeding grounds. Greylag Geese marked on central Europe moulting grounds have not been recorded wintering in Spain since 1986 or in Tunisia and Algeria since 2004. The migration distance and spring arrival of geese indicated an effect of temperature at the breeding site and values of the NAO index. Greylag Geese migrate shorter distances and arrive earlier in milder winters. We suggest that shifts in the migratory behaviour of Central European Greylag Geese are individual temperature‐dependent decisions to take advantage of wintering grounds becoming more favourable closer to their breeding grounds, allowing birds to acquire breeding territories earlier.     

Olfaction and Feeding Behaviour in Juvenile Geese (Anser a. anser and Anser domesticus)

Juvenile geese start reacting to odours at the age of 11 to 20 h. In inexperienced goslings head-shaking is released by the odours of plants on which adult geese would not feed (e.g. lavender, violet etc.). Goslings aged 4 to 9 days show a quantitatively different reaction to different odours, such as sage, dwarf-pine, dill etc. Goslings quickly become habituated to odours, they will not react any more if an odorant is presented too often.     

Interspecific Mate Choice Following Cross-fostering in a Mixed Colony of Greylag Geese (Anser anser) and Canada Geese (Branta canadensis). A Study on Development and Persistence of Species Preferences1

The role of early experience in mate choice and species preference of geese was studied in an experiment where young greylag geese (Anser anser) were cross-fostered by Canada geese (Branta canadensis). In two successive years, all eggs from 9 nests of wild Canada geese were removed and replaced by greylag goose eggs. The young greylag geese then followed their Canada goose foster parents on their southward migration in autumn, to return with them in spring. Of 35 returning birds, all 16 females paired with greylag goose males (100%) whereas of 19 males 5 paired with Canada goose females (14%) and the remaining 14 with greylag goose females (74%). The pair bonds generally persisted as long as both birds were present, but after loss of a partner, the remaining bird usually re-mated. Even when this happened several times during the lifetime of a male, the new mate was always a Canada goose female, showing that the males were sexually imprinted to this species. The Canada goose females which had mated with the greylag ganders also remated when widowed, but their new mate could be either a Canada goose or a greylag goose.     

Description of the Anser anser goose karyotype

The karyotype of the Italian goose originating from Anser anser was characterised on the basis of R and C bands. Chromosomal preparations obtained from an in vitro culture of blood lymphocytes were stained with the RBG and CBG techniques. The RBG technique enabled the analysis of the structure of nine pairs of chromosomes whereas the CBG technique - fourteen pairs ofchromosomes from the total ofeighty goose chromosomes. The morphology and the R and C banding patterns were described. The size and arrangement of the blocks of constitutive chromatin were determined. Ideograms of R and C banded patterns were drawn. The morphological structure of the analysed chromosomes was evaluated.     

High-altitude respiration of birds. The primary structures of the alpha D-chains of the Bar-headed Goose (Anser indicus), the Greylag Goose(Anser anser) and the Canada Goose (Branta canadensis)

The primary structures of the alpha D-chains of the minor component Hb D of Anser indicus, Anser anser and Branta canadensis are presented. Following chain separation by RP-HPLC, the amino-acid sequences were established by automatic Edman degradation of the globin chains and the tryptic peptides. The three chains show a high degree of homology. For the high altitude respiration the alpha 1 beta 1 interface at position alpha 119 is important. For the Bar-headed Goose a mechanism for high altitude respiration involving both Hb A having alanine at position 119 and Hb D having proline at that position is suggested. Furthermore, a possible genetical development of the avian alpha D-gene expression based on a new B alpha-box mutation in the three geese and an unusual 5' splice junction (GT/GC-transition) in the duck gene is discussed. We consider the possibility that the alpha D-gene is an intermediate between a functional gene, reduced in its expression, and a pseudogene.     

Feeding Preferences in Greylag Geese and the Effect of Activated Charcoal

ABSTRACT Greylag geese (Anser anser) can cause serious damage to agricultural fields near wetlands that are attractive for resting and nesting but not for feeding. Alternative plantings or spraying fields may prevent goose damage. We randomly designed 64 plots in spring 2004 and prepared plantings of white clover (Trifolium repens), white clover with perennial ryegrass (Lolium perenne; mixture), fertilized perennial ryegrass (grass), or unfertilized perennial ryegrass. We measured goose-dropping densities in plots as a measure of feeding preference in autumn 2004 (7 weeks), spring 2005 (6 weeks), and autumn 2005 (7 weeks) following removal of a protective fence and vegetation sampling for content analysis in 2004. We also sprayed activated charcoal (20 kg/ha) in a suspension on 32 plots (8/planting) to deter geese in autumn 2004 only. In a second experiment we examined pairs of greylag geese in cages for preferences between grass treated with or without activated charcoal. Charcoal did not deter geese in either experiment. However, dropping density averaged highest for clover (1.01/m²), followed by the mixture (0.65/m²), then fertilized (0.23/m²) and unfertilized grass (0.16/m²). Preferences were consistent in all 3 experimental periods. Fertilized grass reached 31.8 cm in height on average in spring, whereas clover measured 15.4 cm. Crude protein and water-soluble carbohydrate content (g/kg dry matter) was 294 and 49, respectively, in white clover and 183 and 139, respectively, in fertilized grass. We found a positive partial correlation independent of vegetation type between dropping densities and crude protein and a negative correlation with water-soluble carbohydrate content. Thus, to prevent grazing damage to agricultural fields, we recommend planting white clover, strongly preferred by feeding geese, in areas (fallow agricultural or nonagricultural) adjacent to their habitat and not in agricultural fields under production.     

Actual numbers and effects of recreational disturbance on the distribution and behaviour of Greylag Geese (Anser Anser) in the Neusiedler See – Seewinkel National Park Area

The Neusiedler See – Seewinkel National Park area is confronted with a remarkable increase in tourism and recreational activities during the last years. The “Koppel” area, situated on the eastern shore of the lake, is one of the most important breeding sites for Greylag Geese. Behaviour and distribution of the geese on the breeding site as well as touristic activities on the adjacent road leading along the Koppel were examined to investigate relations and interactions between the Greylag Goose population and tourism. Taking into account the excellent weather and breeding conditions in the year 2000 the results of the survey indicate a stable or even rising Greylag population, increasing numbers of visitors and high disturbance frequencies in the vicinity of the study area. The number of disturbances on the adjacent road seems to affect the suitability of the site in general, leading to a specific temporal and spatial distribution of the birds, whereas different disturbance qualities result in changes of the birds behaviour.     

朗德鹅胆汁的化学成分及金属蛋白酶抑制活性研究

应用多种色谱技术进行分离纯化,从朗德鹅胆汁85％乙醇提取物中分离得到6个化合物。经理化性质和光谱数据分析鉴定为苯乙酸（1）、鹅去氧胆酸（2）、鹅去氧胆酸乙酯（3）、棕榈酸-α-单甘油酯（4）、顺-6-十八碳烯酸（5）、（4E）-2-[2＇-hydroxyhexadecanoylamino]-4-octadecane-1,3-diol（6）。化合物1、3、4和6为首次从该属动物胆汁中分得,其中化合物6为首次从陆生动物胆汁中分得的一种神经酰胺类成分。首次对化合物2、4和5进行抑制金属蛋白酶活性的实验,评价了三个化合物的生物活性。     

Effects of wintering greylag geese Anser anser on their Scirpus food plants

Herbivory of Scirpus litoralis and 5 mantimus tubers by wintering greylag geese, Anser anser, was studied at the marshes of the Guadalquivir in southwestern Spain Exclosures were constructed to compare plant growth m grazed and in grazed sites Scirpus luoralis tubers are clustered, with clusters being interconnected by rhizomes Scirpus mantimus tubers develop individually, and are connected by rhizomes The geese forage on individual S mantimus tubers but take entire clusters of S litoralis tubers, from which only one tuber is normally consumed The reproductive mode of S mantimus, the main food plant of the wintering geese, was dependent on tuber size The proportion of tubers whose shoots bear inflorescences decreases with increasing tuber size, and the larger tubers reproduce vegetatively The geese feed on the smaller S mantimus tubers and the smaller S litoralis clusters Reasons for this preference may be that these tubers and clusters are easier to extract and also that small tubers require less time to break down in the gizzard The number of shoots of S litoralis and S mantimus in grazed sites was 88% and 32%, respectively, compared with that in ungrazed sites Nevertheless this difference reflects m part a decrease of 5 litoralis inside some exclosures during a five years period The length of shoots of both species was shorter in grazed than in ungrazed sites The size-related selection of tubers by geese may have a profound effect on the structure and dynamics of these plants populations, and the trade-off between sexual and asexual reproduction However, due to the clonal nature of the plants, interpretation of plant-goose interactions from an evolunonary perspective is difficult because of the elusive unit of selection involved