Environmentally induced morphological variation in the Barnacle Goose,Branta leucopsis

The environmental conditions to which juvenile barnacle geese (Branta leucopsis) were exposed during growth were found to affect their body size at fledging as well as their final adult body size. Small juveniles showed compensatory growth from the time of fledging up to one year of age, but this did not fully compensate the differences in body size that were established before fledging. The variation in protein content in plants eaten during growth could probably explain the observed body size differences, sometimes of more than 10%, between different categories of adult geese. Our results imply that one cannot infer selection on morphological characters from differences between samples of adult birds from different localities or from different cohorts within a population, without first showing that environmental conditions during growth do not affect the development of the characters under study.     

吉林向海发现白颊黑雁

正2018年5月3日傍晚在位于吉林省白城市通榆县的吉林向海国家级自然保护区鹤类核心区青年坝附近(44°59′51.5″N,122°17′52.1″E,海拔168 m)使用NIKON-D4相机800 mm定焦镜头拍摄到1只黑白相间雁类,拍摄距离约120 m。经查阅相关文献(段文科等2017)确定本次发现的鸟类为白颊黑雁(Branta leucopsis)。     

The occurrence and performance of leucistic Barnacle Geese Branta leucopsis

The paper reports the occurrence of whitish 'leucistic' forms in populations of Barnacle Geese Branta leucopsis. A total of 15 (including 11 in the last 21 years) have been reported in the population breeding in Svalbard and wintering in the Solway Firth, northern Britain, whereas the two other populations, though much larger, have produced only one bird of the same type between them in the last 30 years. Leucism is controlled by a single, recessive allele.
The median lifespan of leucistic birds is 2–3 years, compared to 8–10 years for normal plumaged birds. This is because they are sought out by (illegal) hunters. There is no evidence that there is any difference in pairing or breeding performance between white and normal birds, though one male, which is still alive aged 18 years, has produced 13 young; this performance is matched fay less than 2% of normal geese.
It is suggested that the Svalbard population was established recently, from a few founders from the Siberian population; if one or two of these carried the allele controlling leucism, this would explain its much higher prevalence in this population than in the other discrete groups of Barnacle Geese.     

Body size,fitness and compatibility in Barnacle Geese Branta leucopsis

Large-sized Barnacle Geese Branta leucopsis of both sexes had a higher probability of breeding successfully in any particular year and produced more goslings than did smaller birds. Large females paired at an earlier age, suggesting that they were preferred as mates and were likely to have entered the breeding population earlier. The relative sizes of the pair bond members also affected fitness. Most birds were able to maximize their breeding performance by mating with relatively similar sized partners; the greater the size disparity of mates, the lower the breeding performance. This supports the idea that compatibility of mates may be important in determining fitness of the pair. The success of different pair types was also affected by environmental conditions, with certain size combinations doing better in some years and poorly in other years.     

Site fidelity and range size of wintering Barnacle Geese Branta leucopsis

CapsuleBarnacle Geese restrict their movements to relatively few key sites and exhibit considerable variation in ranging behaviour.

Aims To examine individual and seasonal variation in site fidelity, habitat use, range size and foraging strategies of Barnacle Geese Branta leucopsis.

Methods The movements of 18 male Barnacle Geese tagged in two discrete areas were tracked for 3–6 months from late autumn until departure on the spring migration.

Results Tagged geese concentrated their feeding in a relatively small proportion of apparently suitable habitat. Geese moved increasingly further afield in midwinter, and there was a clear predeparture shift to the largest area of relatively undisturbed, and possibly more nitrogen-rich, saltmarsh on the Solway. Birds from one of the two capture sites tended to be more sedentary and have smaller home ranges.

Conclusion There is considerable between-site and inter-individual variation in the degree of site-faithfulness of Barnacle Geese.     

Intraclutch egg-size variation and offspring survival in the Kentish Plover Charadrius alexandrinus

We studied the consequences of intraclutch egg-size variation in Kentish Plovers Charadrius alexandrinus in southern Spain to test the hypothesis that females allocate resources preferentially to eggs with the greatest survival potential. Second eggs were larger and had a greater hatching success than the other eggs in a clutch. However, we did not find unequivocal support for the differential allocation hypothesis, because egg failures according to laying order were not due to the causes predicted by the hypothesis, and the change in egg-size with laying order was not consistent between successive clutches of renesting females. This suggests that nutrient availability during egg formation could act as a proximate factor affecting egg-size independently of laying order. Larger eggs produced heavier chicks and, within broods, heavier chicks were most likely to be recruited into the breeding population. By laying clutches with a larger mean egg volume in replacement clutches, females took longer to lay again after failure of the first clutch. Thus, opposing selective forces may act to increase and decrease egg volume. Although a trade-off between egg-size and clutch-size has not been found in precocial birds, our results suggest that there may be a trade-off between egg-size and fecundity, since an increase in the size of eggs within clutches may limit the time remaining within the season to lay second or replacement clutches.     

The development of a genome wide SNP set for the Barnacle goose Branta leucopsis

Migratory birds are of particular interest for population genetics because of the high connectivity between habitats and populations. A high degree of connectivity requires using many genetic markers to achieve the required statistical power, and a genome wide SNP set can fit this purpose. Here we present the development of a genome wide SNP set for the Barnacle Goose Branta leucopsis, a model species for the study of bird migration. We used the genome of a different waterfowl species, Mallard Anas platyrhynchos, as a reference to align Barnacle Goose second generation sequence reads from an RRL library and detected 2188 SNPs genome wide. Furthermore, we used chimeric flanking sequences, merged from both Mallard and Barnacle Goose DNA sequence information, to create primers for validation by genotyping. Validation with a 384 SNP genotyping set resulted in 374 (97%) successfully typed SNPs in the assay, of which 358 (96%) were polymorphic. Additionally, we validated our SNPs on relatively old (30 years) museum samples, which resulted in a success rate of at least 80%. This shows that museum samples could be used in standard SNP genotyping assays. Our study also shows that the genome of a related species can be used as reference to detect genome wide SNPs in birds, because genomes of birds are highly conserved. This is illustrated by the use of chimeric flanking sequences, which showed that the incorporation of flanking nucleotides from Mallard into Barnacle Goose sequences lead to equal genotyping performance when compared to flanking sequences solely composed of Barnacle Goose sequence.     

The Impact of Changes in Breeding Conditions in the Arctic on the Expansion of the Russian Population of the Barnacle Goose (Branta leucopsis)

Biology Bulletin - In the 20th century, the breeding grounds of the barnacle goose over the territory of Russia included only the Novaya Zemlya Archipelago and Vaygach Island. Until the middle of...     

The population structure of Greenland Barnacle Geese Branta leucopsis on the wintering grounds on Islay

The population structure of the Greenland Barnacle Goose Branta leucopsis at its main winter haunt, the island of Islay, Scotland, was studied using marked individuals caught at three sites on their breeding grounds in east Greenland and on the wintering grounds on Islay. The distribution of individual geese on Islay was found to be non-random. Birds were generally faithful to restricted groups of sites on the island, both within a winter and between consecutive winters. These groups of sites on Islay held different proportions of the individuals from the three catch sites in Greenland. Birds caught together in Greenland were associating in winter more than would be expected if their distribution were random.     

Barnacle Goose (Branta leucopsis) feeding ecology and trophic relationships on Kolguev Island: The usage patterns of nutritional resources in tundra and seashore habitats

Insight into colonization of new areas by invasive species and their relationships with aboriginal species is a major challenge in ecology, allowing for prediction of the outcome of biological invasions. In this context, the current expansion of the Barnacle Goose (Branta leucopsis) is of great interest. The seasonal dynamics of Barnacle Goose feeding and the structure of its diet on Kolguev Island during the nesting and postnesting periods (May 27–July 29) have been examined. The diet structures of the invasive Barnacle Goose and the aboriginal species White-fronted goose (Anser albifrons) and Bean goose (A. fabalis) have been compared. The probability of interspecific competition and the ecological advantages in the diet patterns of these species have been estimated. If the Barnacle Goose population on Kolguev Island continues to increase, this may led to a decline in the population of aboriginal species of geese on the island.     

Possible effects of local enrichment by gulls on feeding-site selection by wintering Barnacle Geese Branta leucopsis

The selection of salt-marsh feeding sites by wintering Barnacle Geese Branta leucopsis was investigated on Schiermonnikoog, The Netherlands. Use of sites by geese was estimated by counts of goose droppings. Geese spent significantly more time grazing in sites with evidence of Herring Gull Larus argentatus and Lesser Black-backed Gull Lfuscus breeding activity than in nearby non-gull sites. The nitrogen content of red fescue grass Festuca rubra was significantly greater in gull sites. We suggest that the geese preferred to feed in these locations because of the improved nutritional value of the grass. The higher nitrogen content of F. rubra in gull sites was most likely the result of nutrient inputs from gull droppings rather than goose droppings.     

Individual inter‐annual nest‐site relocation behaviour drives dynamics of a recently established Barnacle Goose Branta leucopsis colony in sub‐arctic Russia

Avian breeding colonies are generally in a continuous state of flux, some parts growing whilst others shrink as individuals move within the colony on the search for better nest‐sites. We examined the role of experience in breeding patch choice by individually marked Barnacle Geese Branta leucopsis in a recently established colony in sub‐arctic Russia. Individuals failing to reproduce successfully tended to shift nest location further the following season than did successful pairs, and they did so towards the most dense nest aggregations within the colony, where reproductive success was higher. We suggest that individual decisions on nest‐site choice shape the spatial dynamics of this colony.     

Genetic consequences of breaking migratory traditions in barnacle geese Branta leucopsis

Cultural transmission of migratory traditions enables species to deal with their environment based on experiences from earlier generations. Also, it allows a more adequate and rapid response to rapidly changing environments. When individuals break with their migratory traditions, new population structures can emerge that may affect gene flow. Recently, the migratory traditions of the Barnacle Goose Branta leucopsis changed, and new populations differing in migratory distance emerged. Here, we investigate the population genetic structure of the Barnacle Goose to evaluate the consequences of altered migratory traditions. We used a set of 358 single nucleotide polymorphism (SNP) markers to genotype 418 individuals from breeding populations in Greenland, Spitsbergen, Russia, Sweden and the Netherlands, the latter two being newly emerged populations. We used discriminant analysis of principal components, F_ST, linkage disequilibrium and a comparison of geneflow models using migrate ‐n to show that there is significant population structure, but that relatively many pairs of SNPs are in linkage disequilibrium, suggesting recent admixture between these populations. Despite the assumed traditions of migration within populations, we also show that genetic exchange occurs between all populations. The newly established nonmigratory population in the Netherlands is characterized by high emigration into other populations, which suggests more exploratory behaviour, possibly as a result of shortened parental care. These results suggest that migratory traditions in populations are subject to change in geese and that such changes have population genetic consequences. We argue that the emergence of nonmigration probably resulted from developmental plasticity.     

Intraclutch variation in avian eggshell pigmentation: the anaemia hypothesis

Many passerine species lay eggs that are speckled with dark protoporphyrin pigmentation. Because protoporphyrin is mainly derived from the blood, we here formulate and test a new hypothesis that links an increase in anaemia along the laying sequence to within-clutch variation in egg pigmentation. More intense pigmentation is expected if pigments accumulate during enhanced red blood cell production in response to anaemia. Reduced pigmentation is expected if pigments are derived from the degradation of red blood cells that circulate in smaller numbers due to blood loss. To test this hypothesis, we manipulated anaemia in great tit (Parus major) females by infesting the nests with hen fleas (Ceratophyllus gallinae) prior to egg laying. Polychromatophil (i.e., immature red blood cells) percentage, as a measure of blood cell production, was positively correlated with parasite load confirming that female great tits experienced stronger anaemia when infested with haematophagous parasites during egg laying. We found a positive relationship between spot darkness and laying order that weakened under high parasite load. This result suggests that anaemia in females due to blood-sucking parasites led to diminished protoporphyrin from disintegrated red blood cells and hence a decreased deposition of protoporphyrin. However, the overall increase in pigment darkness along the laying sequence suggests that pigments also accumulate by enhanced red blood cell production caused by anaemia due to egg production itself.     

中国鸟类新纪录——加拿大雁

<正>2014年12月21日,在天津市宁河区永定新河水域(39°15′24″N,117°26′2″E,海拔7 m)观察到4只加拿大雁(Branta canadensis)在此栖息觅食,同域亦有少量骨顶鸡(Fulica atra)、绿翅鸭(Anas crecca)、罗纹鸭(A.falcata)及赤膀鸭(A.strepera)在此活动。次日有观鸟者前往观察,未能再发现该群加拿大雁。本次观察到的加     

Bryophyte DNA sequences from faeces of an arctic herbivore, barnacle goose (Branta leucopsis)

We tested DNA extraction methods and PCR conditions for the amplification of bryophyte DNA from barnacle goose (Branta leucopsis) faeces collected from Spitsbergen (Svalbard). Both the Qiagen stool kit and a silica-based extraction method received sufficient DNA from fresh and older droppings, as indicated by successful amplification of the plastid psbA-trnH spacer. Standard Taq polymerase outperformed two hot start polymerases. Sequencing of cloned PCR products revealed at least ten moss and two angiosperm sequences. This first example of identifying bryophyte DNA from faeces will allow analysing moss diets of arctic herbivores with a DNA barcoding approach.     

湖北武汉发现小美洲黑雁

正2015年11月22日,在湖北省武汉市东西湖区府河柏泉段(30°45′10″N,114°9′15″E)观察并拍摄到小美洲黑雁(Branta hutchinsii)1只(图1),隶属于雁形目鸭科黑雁属。该雁所发现之处,为长江一级支流——府河流经武汉柏泉的河段,该河段夏季被高水位所淹,冬季水位降低后,露出草滩,河道则因人为挖筑的堤岸而形成一个面积数百亩的开阔水面,中间有若干泥土堆积而成的小岛。同域分布有豆雁(Anser fabalis)、灰雁(A.anser)、绿头     

Inheritance of body size in the Barnacle Goose under different environmental conditions

Heritabilities, genetic variances and covariances for body size traits, i.e. tarsus length, head length and body mass, were estimated under different environmental conditions in a Barnacle Goose (Branta leucopsis) population. Under poor growth conditions, that is, when average body size of fully grown offspring in a given cohort was small, the offspring-parent regressions and full-sib analyses yielded heritability estimates not significantly different from zero. By contrast, when growth conditions were normal or good the heritability estimates were generally significantly positive. Comparisons of genetic covariance estimates indicated that they also differed across the analysed environmental conditions. This result, together with similar results obtained in studies of passerine birds, suggests that genotype-environment interactions might be frequent within the range of environments normally encountered by birds in natural populations. If general, such results might question the validity of assuming approximate constancy of additive genetic variances and covariances over time and environments in evolutionary models.     

Fitness consequences of egg-size variation in the lesser snow goose

We investigated the relationship between eggsize variation and (a) egg hatching success, (b) chick survival to fledging and recruitment, and (c) adult female survival, over 12 years in the lesser snow goose (Anser caerulescens caerulescens). By comparing the means and variances of egg size for successful and unsuccessful eggs, our aim was to assess the relative fitness of eggs of different sizes and to determine the type of selection operating on egg size in this species. As both egg size and reproductive success vary with age in the lesser snow goose we controlled for the effects of female age. Egg-size variation is very marked in this population, varying by up to 52% for eggs hatching successfully. However, there was no relationship between egg size and post-hatching survival of goslings to fledging or recruitment, either within or between broods, pooling across years. Egg size varied significantly between successful and unsuccessful clutches in only 2 of 33 individual year comparisons. First-laid eggs surviving to onset of incubation, and eggs hatching successfully, were on average larger than unsuccessful eggs, but this was probably due to the confounding effects of female age-specific and sequence-specific egg survival. Variance of egg size differed significantly between successful and unsuccessful eggs in only 3 of 24, and 0 of 21, individual year comparisons for pre- and post-hatching survival respectively. We therefore found little evidence for a relationship between egg-size variation and offspring fitness, or for strong directional, normalising or diversifying selection operating on egg size, in the lesser snow goose. In addition, there was only weak support for the hypothesis that egg-size variation is maintained by temporal variation in selection pressure (sensu Ankney and Bisset 1973). It is likely that egg-size variation represents the pleiotropic expression of alleles affecting more general physiological or metabolic processes. While this does not rule out the existence of alleles with more direct effects on egg size we suggest that their contribution to heritable egg size is small.