Foraging ecology, fluctuating food availability and energetics of wintering brent geese

Changing energy requirements and dramatic shifts in food availability are major factors driving behaviour and distribution of herbivores. We investigate this in wintering East Canadian High Arctic light-bellied brent geese Branta bernicla hrota in Northern Ireland. They followed a sequential pattern of habitat use, feeding on intertidal Zostera spp. in autumn and early winter before moving to predominantly saltmarsh and farmland in late winter and early spring. Night-time feeding occurred throughout and made a considerable contribution to the birds' daily energy budget, at times accounting for >50% of energy intake. Nocturnal feeding, however, is limited to the intertidal, possibly because of predation risk on terrestrial habitat, and increases with moonlight. The amount of Zostera spp., declined dramatically after the arrival of birds, predominantly, but not entirely, due to consumption by the birds. Birds gained fat reserves in the first 2 months but then this was dramatically lost as their major food source collapsed and their daily energy intake declined. Single birds consistently fared worse than paired birds and pairs with juveniles fared better than those without suggesting a benefit of having a family to compete for food. Many birds leave the Lough at this time of reduced Zostera spp. for other sea inlets in Ireland but some remain. Body condition of the latter gradually improved in early spring and reflected a heavy reliance on terrestrial habitats, particularly farmland, to meet the birds' daily energy requirements. However, even in the period immediately before migration to the breeding ground, the birds did not regain the amount of abdominal fatness observed in November. The dramatic changes in available food and requirements of the birds drive the major changes seen in foraging behaviour as the birds evade starvation in the wintering period.     

Factors Influencing Reporting and Harvest Probabilities in North American Geese

ABSTRACT We assessed variation in reporting probabilities of standard bands among species, populations, harvest locations, and size classes of North American geese to enable estimation of unbiased harvest probabilities. We included reward (US$10, $20, $30, $50, or $100) and control ($0) banded geese from 16 recognized goose populations of 4 species: Canada (Branta canadensis), cackling (B. hutchinsii), Ross's (Chen rossii), and snow geese (C. caerulescens). We incorporated spatially explicit direct recoveries and live recaptures into a multinomial model to estimate reporting, harvest, and band-retention probabilities. We compared various models for estimating harvest probabilities at country (United States vs. Canada), flyway (5 administrative regions), and harvest area (i.e., flyways divided into northern and southern sections) scales. Mean reporting probability of standard bands was 0.73 (95% CI = 0.69–0.77). Point estimates of reporting probabilities for goose populations or spatial units varied from 0.52 to 0.93, but confidence intervals for individual estimates overlapped and model selection indicated that models with species, population, or spatial effects were less parsimonious than those without these effects. Our estimates were similar to recently reported estimates for mallards (Anas platyrhynchos). We provide current harvest probability estimates for these populations using our direct measures of reporting probability, improving the accuracy of previous estimates obtained from recovery probabilities alone. Goose managers and researchers throughout North America can use our reporting probabilities to correct recovery probabilities estimated from standard banding operations for deriving spatially explicit harvest probabilities.     

Temporal Patterns of Apparent Leg Band Retention in North American Geese

ABSTRACT An important assumption of mark—recapture studies is that individuals retain their marks, which has not been assessed for goose reward bands. We estimated aluminum leg band retention probabilities and modeled how band retention varied with band type (standard vs. reward band), band age (1–40 months), and goose characteristics (species and size class) for Canada (Branta canadensis), cackling (Branta hutchinsii), snow (Chen caerulescens), and Ross's (Chen rossii) geese that field coordinators double-leg banded during a North American goose reward band study (N = 40,999 individuals from 15 populations). We conditioned all models in this analysis on geese that were encountered with ≥1 leg band still attached (n = 5,747 dead recoveries and live recaptures). Retention probabilities for standard aluminum leg bands were high ( = 0.9995, SE < 0.001) and constant over 1–40 months. In contrast, apparent retention probabilities for reward bands demonstrated an interactive relationship between 5 size and species classes (small cackling, medium Canada, large Canada, snow, and Ross's geese). In addition, apparent retention probabilities for each of the 5 classes varied quadratically with time, being lower immediately after banding and at older age classes. The differential retention probabilities among band type (reward vs. standard) that we observed suggests that 1) models estimating reporting probability should incorporate differential band loss if it is nontrivial, 2) goose managers should consider the costs and benefits of double-banding geese on an operational basis, and 3) the United States Geological Survey Bird Banding Lab should modify protocols for receiving recovery data.     

Effect of different managerial systems on productive and reproductive traits,blood plasma hormones and serum biochemical constituents of geese

A flock of 117, 10-month-old Egyptian geese consisting of 90 females and 27 males were utilized in this investigation. Birds were randomly divided into three equal groups, each made up of three replicates of 10 females and 3 males each. The first group was kept under a pasture system (PS) and allowed to swim in water ducts during the daytime (PS) and kept inside the house during the night. The second group of birds were kept in confinement in a house and fed ad libitum on a commercial feed (intensive system (IS)). Birds in the third group (semi-intensive system (SIS)) were released from the house for 6 h a day and given access to the pasture and water ducts. Each group was housed in three pens (replicates) in the SIS. They were given ad libitum access to the commercial feed when in the house. Each pen measured (2 × 3 m²). Natural mating was practiced during the period from November to the end of May. BW of geese under ISS was significantly (P ⩽ 0.05) higher than those under PS and SIS. Egg number, weight and mass of geese in the SIS system were significantly (P ⩽ 0.05) greater than those of geese in the PS and IS systems. Fertility and hatchability percentages were significantly (P ⩽ 0.05) greater in the PS (84.2% and 88.6%) than in the IS (77.5% and 82.8%) and SIS systems (80.7% and 85.5%). Shell weight and thickness were significantly (P ⩽ 0.05) better in the IS and SIS systems than in the PS system. Geese in the PS and SIS systems exhibited significantly higher plasma estradiol-17 and progesterone than those in the IS. Testosterone was significantly higher in IS than in the other systems. Semen quality factor was significantly higher in the PS and SIS systems than in the IS system. Carcass weight was significantly greater in IS and SIS geese than in PS geese, but the PS system resulted in a decreased percentage skin, abdominal fat and liver. Total amount of meat produced per geese was significantly greater in the SIS than in the IS system and greater in the IS than in the PS system.     

Changes in abundance and spatial distribution of geese molting near Teshekpuk Lake,Alaska: interspecific competition or ecological change?

Goose populations molting in the Teshekpuk Lake Special Area of the National Petroleum Reserve—Alaska have changed in size and distribution over the past 30 years. Black brant (Branta bernicla nigricans) are relatively stable in numbers but are shifting from large, inland lakes to salt marshes. Concurrently, populations of greater white-fronted geese (Anser albifrons frontalis) have increased seven fold. Populations of Canada geese (Branta canadensis and/or B. hutchinsii) are stable with little indication of distributional shifts. The lesser snow goose (Anser caerulescens caerulescens) population is proportionally small, but increasing rapidly. Coastline erosion of the Beaufort Sea has altered tundra habitats by allowing saltwater intrusion, which has resulted in shifts in composition of forage plant species. We propose two alternative hypotheses for the observed shift in black brant distribution. Ecological change may have altered optimal foraging habitats for molting birds, or alternatively, interspecific competition between black brant and greater white-fronted geese may be excluding black brant from preferred habitats. Regardless of the causative mechanism, the observed shifts in species distributions are an important consideration for future resource planning.     

Condition Bias of Decoy-Harvested Light Geese During the Conservation Order

Evidence that decoy harvest techniques primarily remove individuals of poorer body condition is well established in short-lived duck species; however, there is limited support for condition bias in longer-lived waterfowl species, such as geese, where decoy harvest is considered primarily additive because of their high natural survival rates. We evaluated support for the harvest condition bias hypothesis of 2 long-lived waterfowl species, the lesser snow goose (Anser caerulescens caerulescens) and Ross's goose (Anser rossii). We used proximate analysis to quantify lipid and protein content of lesser snow and Ross's geese collected during the Light Goose Conservation Order (LGCO) in 2015 and 2016 during spring migration in Arkansas, Missouri, Nebraska, and South Dakota, USA. In each state, LGCO participants collected birds using traditional decoy techniques and we collected birds from the general population using jump-shooting tactics. Total body lipid content in both lesser snow and Ross's geese varied with age, region of harvest, and harvest type (decoy or jump-shooting). On average, adult lesser snow and Ross's geese harvested over decoys had 60 g and 41 g, respectively, fewer lipids than conspecifics collected using jump-shooting. We observed lower lipid reserves in decoy-shot geese in all 4 states sampled despite general gains in lipid reserves as migration chronology progressed. Our data support that the harvest condition bias extends to longer-lived waterfowl species and during a life-history event (spring migration) in which harvest is not normally observed. In the case of overabundant light geese, the disproportionate harvest of poorer-conditioned lesser snow and Ross's geese may serve as an additional challenge against any realized effects of harvest to reduce the population, in addition to extremely low harvest rates. © 2019 The Wildlife Society.     

Estimation of genetic parameters for growth,carcass and overfeeding traits in a white geese strain

In an experimental strain of white plumage geese created in 1989, two experiments were carried out from 1993 to 1995 in order to estimate genetic parameters for growth, and carcass composition traits in non-overfed animals, and genetic parameters for growth and fatty liver formation in overfed animals. Four hundred and thirty-one non-overfed animals were bred and slaughtered at 11 weeks of age; they were measured for forearm length, keel bone length, chest circumference and breast depth before and after slaughtering. The carcasses were partly dissected in order weigh breast, breast muscle and skin + fat, and abdominal fat. Four hundred and seventy-seven overfed animals were slaughtered at 20 weeks of age; they were measured for "paletot" (breast meat, bone and meat from wings, bone and meat from thigh and legs) weight and liver weight. In these two experiments, the weights had moderate to high heritability values. Breast depth measured on live animals showed a low heritability value. In overfed animals, liver weight showed a high heritability value. Liver weight could be increased by selection without a great effect on "paletot" weight. Thus, obtaining a white plumage geese strain for fatty liver production by selection would be difficult because only 20% of overfed animals had fatty liver. The results did not allow to conclude on the influence of selection on liver weight on carcass traits such as muscle or fatty tissue weight.     

Winter Distribution,Movements, and Annual Survival of Radiomarked Vancouver Canada Geese in Southeast Alaska

ABSTRACT Management of Pacific Flyway Canada geese (Branta canadensis) requires information on winter distribution of different populations. Recoveries of tarsus bands from Vancouver Canada geese (B. canadensis fulva) marked in southeast Alaska, USA, ≥4 decades ago suggested that ≥83% of the population was non-migratory and that annual adult survival was high (Ŝ = 0.836). However, recovery distribution of tarsus bands was potentially biased due to geographic differences in harvest intensity in the Pacific Flyway. Also, winter distribution of Vancouver Canada geese could have shifted since the 1960s, as has occurred for some other populations of Canada geese. Because winter distribution and annual survival of this population had not recently been evaluated, we surgically implanted very high frequency radiotransmitters in 166 adult female Canada geese in southeast Alaska. We captured Vancouver Canada geese during molt at 2 sites where adults with goslings were present (breeding areas) and 2 sites where we observed nonbreeding birds only. During winter radiotracking flights in southeast Alaska, we detected 98% of 85 females marked at breeding areas and 83% of 70 females marked at nonbreeding sites, excluding 11 females that died prior to the onset of winter radiotracking. We detected no radiomarked females in coastal British Columbia, or western Washington and Oregon, USA. Most (70%) females moved ≤30 km between November and March. Our model-averaged estimate of annual survival (Ŝ = 0.844, SE = 0.050) was similar to the estimate of annual survival of geese marked from 1956 to 1960. Likely <2% of Vancouver Canada geese that nest in southeast Alaska migrate to winter areas in Oregon or Washington where they could intermix with Canada geese from other populations in the Pacific Flyway. Because annual survival of adult Vancouver Canada geese was high and showed evidence of long-term consistency, managers should examine how reproductive success and recruitment may affect the population.     

Studies on the transmission of a West African stock of Trypanosoma vivax to rabbits,rats, mice and goats by Glossina morsitans morsitans and G. m. centralis

The cyclical transmission of a West African stock of Trypanosoma vivax by Glossina morsitans morsitans and G. m. centralis was studied. It was possible to transmit this parasite amongst rabbits, rats, mice and goats. Whereas goats and mice succumbed to the disease very rapidly, rats and rabbits showed scant and transient parasitaemia and frequently suppressed the infection. A trypanosome challenge using single infected tsetse showed that goats became infected much more readily than mice. The infected vector can transmit the infection throughout its life but not at every feed.     

Polymorphism of blood plasma proteins in theAnser andBranta genera

An electrophoretical analysis of blood plasma proteins of eightAnser and twoBranta species was performed. Ten polymorphic proteins in blood plasma pattern were distinguished and described: four prealbumin proteins, albumin, three postalbumin proteins, transferrin, and a single posttransferrin protein. Genus-specific and species-specific variants of Pr-1, Al, Pa-3, Pa-X, and Tf proteins were found. The species ofBranta differed inPr-1,Pa-3,Pa-X, andTf loci. TheAnser species differed, apparently, in allele frequencies of described gene loci. A single species-specific protein marker was found in swan geese only. The electrophoretic mobilities of Pr-1, TfB, and PtfA, B, and C were similar for several species ofAnser andBranta genera.     

半胱胺对成年鹅血浆中生长抑素和某些代谢激素的影响

目的:研究半胱胺(CS)对成年鹅生长抑素(SS)和某些代谢激素的影响.方法:14只装有翅静脉瘘管的成年杂交鹅(川白×太湖),经瘘管采取对照期和处理(一次性添喂100 mg/kg bw的半胱胺)后第1、3、5、7 d的血样,用RIA双抗法测定其中激素的含量.结果:实验期第1、3、5和7 d的生长抑素的含量均显著低于对照期(1.89±0.10 μg/L).促甲状腺激素较对照期(2.45±0.31 mIU/L)在第1 d显著下降21.63 %(P<0.05),第3、5 d均降低18.37%(P>0.05),第7 d基本回复正常(P>0.05). 实验期1、3、5和7 d的T4 较对照期(5.41±0.98 μg/L)显著升高(P<0.01);实验期第3 d的T3水平较对照期(1.05±0.06 μg /L)高36.19 %(P<0.01);同样,胰岛素在实验期的第5 d显著高于对照期(P<0.05).结论:CS能够降低成年鹅血液中SS含量,使T4、T3和胰岛素水平升高,提高了机体的代谢水平,同化作用加强,从而有利于生长.     

PATTERNS IN TREE BALANCE AMONG CLADISTIC,PHENETIC, AND RANDOMLY GENERATED PHYLOGENETIC TREES

I examine patterns in tree balance for a sample of 208 cladograms and phenograms from the recent literature. I provide an expression for expected imbalance under a simple, uniform-rate random speciation model, and I estimate variances by simulation for the same model. Imbalance decreases with tree size (number of included taxa) in both theoretical and literature trees. In contrast to previous suggestions, I find cladistic trees to be no more imbalanced than phenetic trees when confounding variables are appropriately controlled. The degree of imbalance found in literature trees is inconsistent with the uniform-rate speciation model; this is most likely a result of variability in speciation and extinction rates among real lineages. The existence of such variation is a necessary (but not sufficient) condition for the operation of the macroevolutionary processes of species sorting and species selection.     

Mitochondrial DNA Cleavage Patterns Distinguish Independent Origin of Chinese Domestic Geese and Western Domestic Geese

It has generally been assumed, based on morphology, that Chinese domestic goose breeds were derived from the swan goose (Anser cygnoides) and that European and American breeds were derived from the graylag goose (Anser anser). To test the validity of this assumption, we investigated the mtDNA cleavage patterns of 16 Chinese breeds and 2 European breeds as well as hybrids produced between a Chinese breed and a European breed. After 224 mtDNAs, isolated from the Chinese and European breeds, were digested by 19 restriction endonucleases, variations of the cleavage patterns were observed for four enzymes (EcoRV, HaeII, HincII, and KpnI). All Chinese breeds and their maternal hybrids except the Yili breed showed an identical haplotype, named haplotype I or the Chinese haplotype; the European breeds and the Yili breed showed another haplotype, named haplotype II or the western haplotype. None of the haplotype found in the Chinese type was detectable in the western type and vice versa. The two haplotypes were found to differ from each other at 8.0% of the sites surveyed and with a 0.72% sequence divergence. Using 2% substitution per million years calibrated from the genera Anser and Branta, the two domestic geese haplotypes were estimated to have diverged approximately 360,000 years ago, well outside the 3000-6000 years in domestic history. Our findings provide the first molecular genetic evidence to support the dual origin assumption of domestic geese in the world. Meanwhile, the four mtDNA restriction fragment length polymorphisms can be used as maternal genetic markers to distinguish the two types of domestic geese.     

基于卫星跟踪的灰雁秋季活动特征与生境利用研究

营养和能量有效的积累对候鸟能否顺利完成迁徙具有重要意义。2015年8月至10月在内蒙古图牧吉湿地,利用卫星跟踪技术对灰雁的活动特征、生境利用等方面进行了研究,以期阐明灰雁在秋季如何有效积累能量以满足迁徙前的生理需求。我们采用增强型植被指数(EVI)分析了灰雁的生境特征,运用核密度分析法(KDE)计算了日间和夜间活动区面积,以及对不同月份的平均活动距离进行了分析。结果表明,8至10月间,灰雁活动位点的EVI值逐月递减,并且逐渐向南移动,趋向于水域集中,增加了对湖泊的利用,同时减少了对草地的利用;灰雁的活动区面积逐月递增,日间活动区面积大于夜间;灰雁在日间、夜间及平均活动距离均呈递增的趋势,每天凌晨及黄昏都出现较长时间的活动。由于8至10月间气温逐渐降低,从草地中可以获取的潜在食物资源减少,灰雁通过逐渐向水域较为丰富的区域移动,活动区面积逐渐增大,增加活动距离提高食物的获取量等确保获取足够的食物和能量满足迁徙的需求。     

A kinetic study of the natural induction of liver steatosis in Greylag Landaise geese: the role of hyperphagia

We have previously demonstrated that a sharp rise in feed intake (hyperphagia) and spontaneous liver steatosis could be experimentally induced in domestic Greylag geese by combining a short photoperiod and a sequence of feed restriction followed by ad libitum corn feeding during the fall and the winter. In this previous work, however, individual feed intake could not be recorded. The present study aimed at evaluating the relationship between level and pattern of hyperphagia and liver weight with an individual control of feed intake in individually housed (IH) geese, while comparing the performances with group housed (GH) geese. A total of 300 male geese of 19 weeks of age, were provided with corn ad libitum after an initial feed restriction period. From 21 to 23 weeks of age, the daylight duration was progressively reduced from 10 to 7 h and kept as such until the end of the experiment (week 36). In all, 30 GH and 30 IH geese were slaughtered at 19, 27, 30, 32 and 36 weeks of age. Feed intake was measured per group in GH geese and individually in IH geese. During the 1^st week of corn feeding, the average feed intake rose up to 600 g/goose per day in GH geese but not in IH geese where the feed intake rose gradually from 300 to 400 g/day. The liver weight increased from 93 g (week 19) to 497 g (week 32; P<0.05) in GH birds. In IH birds, liver weights were, on average, much lower (ranging from 220 to 268 g) than in GH birds (P<0.05). In GH and IH bird, the variability in the individual response to corn feeding was very high (liver weight c_v ranging from 63% to 83% depending on slaughter age). A close correlation between corn consumption and liver weight was evidenced in IH birds at each slaughter age (R² ranging from 0.62 to 0.79), except at 36 weeks of age where this correlation was weak (R²=0.14). The variability in the extent of liver steatosis is very high and our results in IH birds clearly point out the major role of hyperphagia, mainly at the beginning of the ad libitum corn feeding period, on the development of spontaneous liver steatosis.     

Mercury distribution in sediment profiles from lakes of the high pantanal,Mato Grosso State,Brazil

Sediment cores from lakes located in the Pantanal Swamp, Central Brazil were analysed for the distribution of mercury released by the local gold mining. Atmospheric transport is the only pathway of mercury contamination of these remote lakes. Mercury concentrations were higher at the surface of sediments (62 to 80 ug.kg^–1) decreasing to values of 20 to 30 ug.kg^–1 in deeper layers. Mercury deposition rate was estimated as 90 to 120 ug Hg.m^–2yr^–1 Although mercury concentrations were much lower than in industrialized areas, mercury deposition rate for these Pantanal lakes is of the same order of magnitude of deposition rates measured in lakes in industrialized areas     

Exceptional growth rates of captive loggerhead sea turtles,Caretta caretta

Twelve loggerhead sea turtle hatchlings (Caretta caretta) were removed from a nest site (A) at the Back Bay National Wildlife Refuge (U.S. Fish and Wildlife Service), Virginia Beach, VA. Hatchlings were distributed among study participants, and raised in captivity for a period of two years. Growth of the loggerheads was recorded weekly by straight-line caliper measurements of carapace lengths as well as measurements of total weights. Growth rates from the present study were much greater than those measured in previous studies. Mean weights for Nest A turtles at 1.5 years ranged from 10.3 to 17.6 kg, with one exceptional individual reaching 20.0 kg. The data from this study provide new insights into the early growth potential of loggerhead sea turtles. How this accelerated development may affect sexual maturity and post-release viability remain to be determined. © 1993 Wiley-Liss, Inc.     

半胱胺对鹅胰液分泌及胰酶活性的影响

目的 :研究半胱胺对鹅胰液分泌及胰酶活性的影响。方法 :12只装有胰腺～十二指肠长久性瘘管的成年鹅。试验采用自身对照 ,试验期在日粮中一次性添加半胱胺 (10 0mg/kgbw)。连续收集计量胰液并测定胰酶活性。 结果 :①半胱胺使鹅胰液的分泌速率较对照期显著上升 (2 4 0 .16 % ,P <0 .0 1) ,其中白天升高 2 34.4 5 % ,夜间增高了2 5 3.70 %。②试验期单位容积胰蛋白酶的活性较对照期升高了 4 9.0 5 % (P <0 .0 1) ,而胰脂肪酶和胰淀粉酶的活性却较对照期分别降低了 2 5 .4 4 %和 2 1.95 % ,且变化幅度具有昼夜的差别。③试验期胰腺每小时分泌胰蛋白酶、胰脂肪酶和胰淀粉酶的总活性较对照期分别升高 4 0 6 .88% (P <0 .0 1)、15 3.5 8% (P <0 .0 1)和 16 6 .5 9% (P<0 .0 1) ,白天增加的幅度较夜晚大。结论 :半胱胺能促进鹅胰液的分泌 ,增加胰液中蛋白酶、脂肪酶和淀粉酶分泌的总量 ,从而提高鹅对饲料的消化能力 ,适应机体生长对营养的需求     

Carbon flow across the sediment-water interface in Lake Vechten,The Netherlands

The turnover and exchange rates, as well as the diffusion processes, concerning the input and output of carbon compounds at the mud-water interface, were studied. The carbon input rates were derived from the annual sedimentation rates of particulate organic matter (about 1 100 kg C · yr⁻¹). The nature of the sedimented POC, and its breakdown pathways and turnover rates towards important metabolic intermediates in methanogenesis, were examined. The breakdown kinetics ofChlorella cell walls, a dominant green alga in Lake Vechten, was studied using U-¹⁴C-labelled cell walls. The breakdown of the cell walls appears to the rate-limiting step in anaerobic mineralization. Using first order kinetic equations, and HPLC and GLC and radio-chemical methods, turnover rate constants (k-values) of between 0.18 and 0.32 day⁻¹ and pool sizes of algal cell walls of 37 to 80 μg · g⁻¹ wet mud were found, giving turnover rates of 7.7 to 25.6 μg · g⁻¹ · day⁻¹ of cell wall material. The turnover rates (k-values between 0.07 and 0.31 h⁻¹) of acetate, the most important breakdown product, and its concentration gradients (between 5 and 30 μmol) and diffusion coefficient (D_s = 2.2 × 10⁻⁶ cm² · s⁻¹) just in and above mud-water interface, was quantified. The diffusion of acetate, within the sediments, could not account for the turnover rates observed. Finally, from acetate flux data and from those on the rates of formation of carbon dioxide and methane, the output of carbon and its cycling in Lake Vechten are discussed.