Spatial proximity among adult siblings in greylag geese (Anser anser): evidence for female bonding?

By staying close to allies, individuals may enjoy benefits through social support. In the socially monogamous greylag goose (Anser anser), pair-partners, parents, and even human foster parents may provide social support, facilitating access to resources or reducing agonistic pressure. In the present work, we analysed the spatial distribution of individuals within a semi-feral flock of 120 greylag geese, which contained 23 adult sibling groups of 2–4 individuals from 2 to 12 years old. During resting periods we scored dyadic distances between 28 focal individuals of different social categories, their siblings and unrelated control individuals of the same age. Adult female siblings (i.e. those hatched in the same year and raised together) rested significantly closer to each other than to either their brothers or unrelated control individuals. We attribute this to social attraction rather than to just a common preference for the same resting site. Thus, kinship bonds as expressed by cohesion might persist into adulthood, at least in the females. We discuss the potential benefits of proximity between related individuals with regard to reduced social stress via social support. Received: 21 February 2000 / Received in revised form: 16 May 2000 / Accepted: 17 May 2000     

Behavioural and physiological correlates of personality in greylag geese (Anser anser)

Personality means suites of correlated behavioural traits, also referred to as “behavioural syndromes” or “personality dimensions”. Across animal taxa similar combinations of traits seem to prevail, which may have proximate foundation in common neuroendocrine mechanisms. Hitherto, these have been rarely studied in intact social settings. We investigated personalities of greylag goose males from a free-roaming flock that shows complex social relationships. In connection with our longitudinal study on the consistency of behavioural and physiological responses to multiple challenges, we asked whether and how single, personality-related behavioural traits correlate with each other to form personality dimension(s). We tested whether these dimensions were related to physiological characteristics that previously showed limited plasticity (heart rate (HR), baseline and stress-induced excreted immuno-reactive corticosterone (BM), and testosterone metabolites levels) and, furthermore, to age, body measures, and dominance rank. Principal-components analysis based on behavioural variables revealed two factors: 51.1% of variability was explained by “aggressiveness” and a further 19.1% by “sociability”. “Aggressiveness” comprised correlated measures of aggression, subordinance, boldness, vigilance, and proximity to the mate. This “aggressiveness” positively correlated with stress-induced BM levels, the HR increase during aggressive interactions, and with dominance rank, which may suggest proximate and functional contingencies of this personality dimension.     

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     

Dynamic body acceleration increases by 20% during flight ontogeny of greylag geese Anser anser

Despite our knowledge of the biophysical and behavioural changes during flight ontogeny in juvenile birds, little is known about the changes in the mechanical aspects of energy expenditure during early flight development, particularly in migratory species. Here, we investigate in a unique experimental setup how energy expended during flights changes over time beginning with early ontogeny. We calculate overall dynamic body acceleration (ODBA) as a proxy for energy expenditure in a group of hand raised greylag geese Anser anser trained to fly behind a microlight aircraft. We propose two potential hypotheses; energy expenditure either increases with increasing physiological suitability (the ‘physical development hypothesis’), or decreases as a result of behavioural improvements mitigating flight costs (the ‘behavioural development hypothesis’). There was a significant temporal increase of flight duration and ODBA over time, supporting the ‘physical development hypothesis’. This suggests that early on in flight ontogeny behavioural development leading to flight efficiency plays a weaker role in shaping ODBA changes than the increased physical ability to expend energy in flight. We discuss these findings and the implications of flight development on the life history of migratory species.     

Size-related consumption of Scirpus maritimus tubers by greylag geese Anser anser explained by their functional response

To explain the preference of wintering greylag geese Anser anser for small Scirpus maritimus tubers (<10mm) over larger ones, our hypothesis was that the former would provide higher intake rates. This 'consumption rate hypothesis' was tested experimentally by deriving the functional responses of geese feeding on tubers of three contrasting sizes. Goose consumption rates were measured as: (i) feeding rate (tubers/min) and (ii) instantaneous intake rate (g fresh weight/min) on various tuber densities (5-200 tubers/tray). Geese had linear functional responses over the range of tuber densities offered, and tuber size affected their consumption rate. The results were then used to re-examine intake rates according to relative biomass of tubers found in the wild. In support of our hypothesis, the larger tubers allowed the lower intake rates. Foraging mechanisms that possibly control the tuber ingestion rate of geese were explored. After controlling (through chemical analyses) that nutritional components of tubers do not differ between sizes, it was concluded that geese preference is mainly due to size-related constraints (i.e. handling time) on their ingestion rates. Additional limiting factors (tuber extraction, digestion capacity) which are likely to constrain food intake of wild geese are also discussed.     

Changes in body mass and organ size during wing moult in non-breeding greylag geese Anser anser

The "cost-benefit" hypothesis states that specific body organs show mass changes consistent with a trade-off between the importance of their function and cost of their maintenance. We tested four predictions from this hypothesis using data on non-breeding greylag geese Anser anser during the course of remigial moult: namely that (i) pectoral muscles and heart would atrophy followed by hypertrophy, (ii) leg muscles would hypertrophy followed by atrophy, (iii) that digestive organs and liver would atrophy followed by hypertrophy and (iv) fat depots be depleted. Dissection of geese captured on three different dates during wing moult on the Danish island of Saltholm provided data on locomotory muscles and digestive organ size that confirmed these predictions. Locomotory organs associated with flight showed initial atrophy (a maximum loss of 23% of the initial pectoral muscle mass and 37% heart tissue) followed by hypertrophy as birds regained the powers of flight. Locomotory organs associated with running (leg muscles, since geese habitually run to the safety of water from predator-type stimuli) showed initial hypertrophy (a maximum gain of 37% over initial mass) followed by atrophy. The intestines and liver showed initial atrophy (41% and 37% respectively), consistent with observed reductions in daily time spent feeding during moult, followed by hypertrophy. The majority of the 22% loss in overall body mass (mean 760 g) during the flightless period involved fat utilisation, apparently consumed to meet shortfalls between daily energetic needs and observed rates of exogenous intake. The results support the hypothesis that such phenotypic plasticity in size of fat stores, locomotor and digestive organs can be interpreted as an evolutionary adaptation to meet the conflicting needs of the wing moult.     

Isolation and characterization of microsatellite marker loci in the greylag goose (Anser anser)

Ten novel polymorphic microsatellite loci were isolated and characterized from the greylag goose, Anser anser, a long-term monogamous and biparental bird. Additionally, five new primers pairs were designed based on previously published microsatellite locus sequences from closely related species. Multiplex polymerase chain reactions conditions were optimized for all 15 primer pairs. The number of alleles ranged from two to 12 per locus with an observed heterozygosity ranging from 0.07 to 0.85. This marker set will be used to determine rates and origins of extra-pair and parasitic young in a population of individually banded greylag geese with known life histories.     

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.     

Isotopic evidence for endogenous protein contributions to greylag goose Anser anser flight feathers

Feather stable isotope composition may not reflect local isoscapes in which they were grown if supplemented with protein of endogenous origin. Thus, feather isotope analysis, combined with knowledge of local isoscapes can be used to infer endogenous nutrient composition to feathers in cases where birds travel to moult. We investigated this possibility in a study of flightless moulting greylag geese Anser anser on the Danish island of Saltholm, which are known to mobilise endogenous protein stores (acquired at previous terrestrial staging locations in Sweden) to reconstitute muscle blocks and organs whilst feeding on a saltmarsh (i.e. marine-influenced) diet with contrasting stable isotope ratios. We used stable isotope (δ¹³C, δ¹⁵N) measurements to test the prediction that new-grown flight feathers would have stable isotope values intermediate between those derived from a purely terrestrial C₃ diet and one composed purely of saltmarsh plants. Feather δ¹³C and δ¹⁵N values were intermediate between those expected for feather material derived from local saltmarsh (i.e. exogenous) food items and Swedish terrestrial (endogenous muscle) sources, suggesting a mixing of endogenous and exogenous sources. These results confirm that moult migrant Anatidae exploit body stores to meet specific protein needs during the flightless period of remige regrowth and caution against the use of feather stable isotope ratios as direct indicators of the isotopic environment in which they were regrown, where endogenous contributions may occur.     

The isolation and characterization of Campylobacter jejuni subsp. jejuni from domestic geese (Anser anser)

AIMS: The objectives of this study were to determine the presence of thermophilic Campylobacter spp. in free range domestic geese, and to characterize isolated strains using phenotyping criteria and SDS-PAGE of whole-cell proteins. METHODS AND RESULTS: Forty cloacal swabs from two different flocks of domestic geese were examined. All Camp. jejuni strains isolated from geese were biotyped using the Lior biotyping scheme. Twelve Camp. jejuni isolates were also tested for their susceptibility to 17 different antibacterial agents by a disc diffusion METHOD: Fourteen of the isolates were also subjected to SDS-PAGE. All of the geese examined were found to harbour Camp. jejuni. Six geese carried more than one species of Campylobacter. All strains examined were susceptible to various antibiotics but resistant to penicillin G and cephalothin. Eleven strains (92%) were resistant to sodium cefuroxime, and eight (67%) were resistant to cloxacillin, ampicillin and colistin sulphate. Three strains (25%) were resistant to tetracycline, and one strain was resistant to sulfamethoxazole/trimethoprim and kanamycin. Nine strains were subtyped as Camp. jejuni subsp. jejuni biotype II and the remaining ones as biotype I. There were 96% and 100% similarities between all the strains examined by SDS-PAGE. CONCLUSION: This study showed that Camp. jejuni were common in the intestinal tract of domestic geese. SIGNIFICANCE AND IMPACT OF THE STUDY: Geese should be considered as potential reservoirs for human and animal campylobacteriosis. The antibiotic resistance data from this study also showed that fluoroquinolone resistance, which appears to be a problem in poultry isolates in some countries, is not yet a problem in these geese.     

Serial agonistic attacks by greylag goose families, Anser anser, against the same opponent

It is known from primates that alliance partners may support each other's interests in competition with others, for example, through repeated agonistic attacks against a particular individual. We examined serial aggressive interactions between greylag goose families and other flock members. We found that repeated attacks towards the same individual were common and that up to five serial attacks by family members followed an initial attack. Family size did not affect the frequency of such serial attacks. Juvenile geese evidently benefited most from active social support through serial attacks. About 60% of the juveniles' lost primary interactions were subsequently reversed by another family member. This may be one of the reasons why juveniles rank higher in the social hierarchy than would be expected from their age and size alone. Losses in serial attacks predominantly occurred against other, presumably higher-ranking, family geese and ganders. We propose three major functions/consequences of serial attacks. Analogous to primates, serial attacks in greylag geese may serve to reinforce a losing experience of an opponent defeated in a preceding attack. On the side of the winning family, serial attacks may reinforce the experience of winning. Both winning and losing experiences are linked with physiological consequences in higher vertebrates, affecting the future social performance of winners or losers. Finally, serial attacks may signal the agonistic potential of a family to other flock members. This is supported by heart rate data, which indicate that greylags are competent to interpret third-party relationships.     

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.     

The histological structure and histochemistry of the mucosa of the nasal conchae in geese,Anser anser

We investigated the histological structure and histochemistry of the nasal conchae of geese and compared these structures with those of other avian species. The rostral, middle and caudal conchae were dissected from the nasal cavity of eight geese, fixed in Carnoy’s solution and embedded in paraffin. The entrance of the rostral concha was lined by keratinized stratified squamous epithelium, which toward the middle concha was replaced by modified keratinized squamous epithelium, the deep layer of which opened into tubular glandular structures containing secretory epithelium on crypt-like invaginations. The lamina propria of the rostral concha contained numerous Grandry’s and Herbst corpuscles, which are pressure-sensitive receptors peculiar to waterfowl. The lamina propria of the middle concha contained solitary lymphoid follicles and lymphocyte infiltrations. The cartilaginous component of the middle concha was highly convoluted and resembled a spiral of two and a half scrolls, which were lined by pseudostratified columnar epithelium. We observed that unlike mammals, this epithelium contained mostly intraepithelial alveolar glands rather than goblet cells. The caudal concha was similar to the middle concha, but less convoluted. It was lined by olfactory epithelium and its lamina propria contained serous Bowman’s glands as well as olfactory nerve fibers. Histochemical examination demonstrated that while none of the conchae contained sulfated mucins, except for the cartilage, the intraepithelial glands of the rostral and middle conchae contained mostly carboxylated acidic mucin and some neutral mucin, and were thus of the mixed type. The outermost scroll of the spiral of the middle concha contained some periodate-Schiff stained mucins. Of the glands of the mucosa of the middle concha, the deep tubuloalveolar glands in the convex parts of the scrolls contained primarily acidic mucins, while the shallow intraepithelial alveolar glands in the concave parts of the scrolls contained primarily neutral mucins. Our findings indicate that the rostral and caudal conchae primarily have a sensory function and the middle concha participates in mucosal defense.     

Relationship between wild greylag and European domestic geese based on mitochondrial DNA

The origins of the European domestic goose are uncertain. The available information comes from archaeological findings and historical literature, but genetic evidence has hitherto been scarce. The domestic goose in Europe is derived from the greylag goose (Anser anser), but it is not known where the initial domestication took place and which of the two subspecies of greylag goose was ancestral. We aimed to determine the amount and geographical distribution of genetic diversity in modern populations of greylag geese as well as in different breeds of the domestic goose to make inferences about goose domestication. We studied DNA sequence variation in the mitochondrial control region of greylag geese from multiple populations across Europe and western Asia as well as specimens of domestic geese representing 18 modern breeds and individuals not belonging to any recognised breed. Our results show notable differences in genetic diversity between different greylag goose populations and the presence of six mitochondrial haplogroups which show a degree of geographical partitioning. The genetic diversity of the domestic goose is low, with 84% of sampled individuals having one of two major closely related haplotypes, suggesting that modern European domestic geese may derive from a narrow genetic base. The site of domestication remains unresolved, but domestic geese in Turkey were unusually diverse, indicating the importance of further sampling in the vicinity of the eastern Mediterranean and the Near East. There appears to be past or ongoing hybridisation between greylags and domestic geese in particular areas, consistent with field observations.     

Preliminary report on two new plasma protein polymorphisms in the goose (Anser anser)

Two-dimensional agarose gel (pH 8.6)-horizontal polyacrylamide gel (pH 9.0) electrophoresis of plasma proteins in the goose was done. This method resulted in improved separation of proteins in the pre-transferrin and transferrin regions. Preliminary evidence was presented for the existence of two new plasma protein polymorphisms.     

Preliminary report on two new plasma protein polymorphisms in the goose (Anser anser)

Two-dimensional agarose gel (pH 8.6)-horizontal poly acrylamide gel (pH 9.0) electrophoresis of plasma proteins in the goose was done. This method resulted in improved separation of proteins in the pre-transferrin and transferrin regions. Preliminary evidence was presented for the existence of two new plasma protein poly morphisrns.     

Zur Feinstruktur der eosinophilen Granulozyten der Hausgans (Anser anser dom.)

Zusammenfassung Die Feinstruktur der Blut-Eosinophilen wurde bei 7 klinisch gesunden Toulouser Hausgänsen (Anser anser dom.) untersucht. Sie unterscheidet sich deutlich von der der Heterophilen.Die Form der Eosinophilen ist oval bis rundlich. Das Chromatinmaterial liegt hauptsächlich in dichten Chromocentren. Unter den Zellorganellen treten Mitochondrien, die sich in osmiophile Granula umwandeln, Vakuolen, multivesikuläre Körper und Mikrofilamente hervor. Für die Eosinophilen bezeichnend sind zahlreiche ellipsoide, ovoide oder rundliche osmiophile Granula mit einem häufig band- oder stabförmigen Internum. An dem Internum läßt sich eine Substruktur aus parallel geordneten, massendichten Banden nachweisen, die bisher nur bei Säugetieren sichtbar gemacht wurde. Die ultrastrukturellen und biochemischen Merkmale der internumhaltigen Granula der Eosinophilen sprechen eher für das Vorliegen eines ionotropen mikrohetercgenen Gels als eines kristallähnlichen Körpers. Im Internum einiger Granula zeigen sich membranöse, vesikuläre und tubulöse Strukturen, die Ausdruck einer bestimmten Entwicklungsphase sein können.

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On the finestructure of the goose eosinophils

Summary Investigations of the fine structure of blood eosinophils of seven clinically healthy Toulouse-geese (Anser anser dom.) reveal striking differences between these cells and the heterophils.The eosinophils are characterized by an oval or nearly round profile. The nucleus contains chromatin mainly concentrated in dense chromocentres. Mitochondria turning into osmiophilic granules, vacuoles, multivesicular bodies, and microfilaments are prominent cytoplasmatic elements. Typical cytoplasmic organelles are numerous elliptic, oval, or round osmiophilic granules, frequently containing a nearly bacilliform internum. The internum possesses a substructure of parallel arranged dense bands, until now observed only in mammalian eosinophils. The ultrastructural and biochemical characteristics imply that the internum-containing granules of the eosinophils represent a state of an ionotropic, microheterogeneous gel and not that of a cristalloid body. The appearence of membraneous, vesicular, and tubular structures in the internum of several granules may be an equivalent of a certain phase of development.

Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

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).