Ray T. Alisauskas

NUTRIENT RESERVES AND THE ENERGETICS OF REPRODUCTION IN AMERICAN COOTS

To investigate the bioenergetics of reproduction in American Coots (Fulica americana) we collected 108 males and 93 females at Delta Marsh, in southern Manitoba, in 1981. Prenesting and nesting birds were analyzed for fat, protein, and ash content in the nonreproductive tissue. For females, these values were compared to the nutrient require- ments of the reproductive tissue during egg-laying. We suggest that feeding conditions before arrival can affect subsequent reproductive output. Fat reserves may function as a threshold that influences the initiation of breeding; protein reserves and time of arrival influence the timing of a nesting attempt. We infer that territory quality is important and that it can result in the termination of laying before nutrient reserves are depleted. By distributing costs of clutch formation before (through nutrient storage) and after (through increased biparental care of eggs and young) clutch formation, the required energy intake concurrent with egg-laying is substantially reduced in female coots. Received 23 January 1984, accepted 18 August 1984. To understand avian breeding strategies, it is necessary to know the temporal distribution of costs and how nutrients are obtained to meet them (Drobney 1980). Because of the disparity in gamete size, female birds have much greater nutrient demands during reproduction than do males. The male, however, can influence how a females demands are met (e.g. through nest building and territorial defense), thereby al- lowing her to spend more time feeding. Recent research has suggested that there is a great in- terspecific variation in how females and males obtain nutrients for reproduction: most arc- tic-nesting geese rely almost exclusively on en- dogenous reserves (Ankney and MacInnes 1978, Raveling 1979, but see Ankney 1984), prairie- nesting ducks (Krapu 1981), Wood Ducks (Aix sponsa, Drobney 1980), and Red-billed Queleas (Quelea quelea, Jones and Ward 1976) utilize both endogenous and exogenous nutrients, and Brown-headed Cowbirds (Molothrus ater, Ank- ney and Scott 1980) rely on exogenous nu- trients. As pointed out by Drent and Daan (1980), however, much more research is needed

Arctic climate, spring nutrition, and recruitment in midcontinent lesser snow geese

I examined fall age ratios of midcontinent lesser snow geese (Chen caerulescens) shot by hunters in the Central and Mississippi flyways (1962-1999), and spring nutrient reserves in southern Manitoba, Canada (Apr-May, 1983-1984, 1988-1993). Age ratios were inversely related (95%[β S ] = -0.170 ± 0.068) to severity of arctic weather as indexed by average snow depth during May and June, and mean June temperatures. After accounting for this effect, age ratios declined 0.017 ± 0.009 immatures/adults/year during 1962-1999. Body size, indexed by principal components analysis of 10 morphological measures, declined -0.082 ± 0.057 per year during 1983-1993. Body mass, fat, protein, and mineral reserves showed considerable annual variation, but only mass (9.8 ± 1.6 g/day) and body fat increased during spring staging in Manitoba; rate of increase in body fat ranged from 6.0 ± 2.9 g/day during 1990 to 17.5 ± 3.8 g/day during 1993. Using model-averaged estimates from a set of candidate models, fall age ratios (controlling for differences between flyways and annual severity of arctic spring weather) were related to body mass (0.0011 ± 0.0008 immature/adult/g), and fat during early staging during April (0.00092 ± 0.00072 immatures/adult/g), but the relationship with body fat during late staging in May was not as strong (0.00020 ± 0.00022 immatures/adult/g); age ratios were unrelated to variation in protein or mineral reserves. Linkages between recruitment in the Arctic and nutritional state on the prairies the previous spring suggest that management on spring staging areas could influence dynamics of the midcontinent population of lesser snow geese, and perhaps of other Arctic-nesting goose populations.

Harvest, Survival, and Abundance of Midcontinent Lesser Snow Geese Relative to Population Reduction Efforts

ABSTRACT We assessed the effectiveness of an extensive and unprecedented wildlife reduction effort directed at a wide-ranging migratory population of geese. Population reduction efforts that targeted several populations of light geese (greater snow geese [Chen caerulescens atlantica], lesser snow geese [C. c. caerulescens], and Rosss geese [C. rossii]) began in 1999 in central and eastern North America. Such efforts were motivated by a broad consensus that abundance of these geese was causing serious ecological damage to terrestrial and salt marsh ecosystems in central and eastern parts of the Canadian Arctic and subarctic regions along Hudson Bay. Starting in February 1999, special conservation measures (or, in the U.S., a conservation order) were added to the respective federal regulations that permitted hunters to take snow geese (in parts of Canada and the U.S.) and Rosss geese (in parts of the U.S.) during specified harvest periods outside of the hunting season. These measures were accompanied by increase or removal of daily kill and possession limits and by permissions to use previously prohibited equipment for hunting these species in certain regions of the continent. The intent was to reduce adult survival through increased hunting mortality, which was judged to be the most cost-effective approach to reversing population growth. Our principal goal was to assess the effectiveness of reduction efforts directed at the midcontinent population of lesser snow geese, which was thought to be the most serious threat to arctic and subarctic ecosystems of the 3 light goose populations. Our multiple objectives included the estimation and detection of change in the response measures of total annual harvest, harvest rate, survival rate, and abundance, using the 1998 hunting period (defined as 1 Aug 1998 to 31 Jul 1999) as a point of reference. We used information about hunter recoveries of leg-banded snow geese and estimates of regular-season harvest to estimate 1) conservation-order harvest and total annual harvest, 2) geographic and temporal distribution of recoveries by age class, 3) survival and recovery probability, and 4) abundance of snow geese each August using Lincolns (1930) method. We also modeled population growth to infer the form of population response to management efforts. Toward that end, we also proposed a method of estimating conservation-order harvest and tested for differences in band-reporting rate between Canada and the United States. Overall, the balance of evidence favored the conclusion that the midcontinent population has continued to grow during the conservation order, although perhaps at a reduced rate. We suggest that annual rate of population growth (), derived from estimates of annual population size in August, likely provides the most reliable inference about change in the midcontinent population. There was a decline in annual survival probability between these 2 periods from about 0.89 to about 0.83 among snow geese from the southern-nesting stratum (south of 60°N latitude), thought to compose about 10% of the midcontinent population. However, we detected no change in the much larger northern-nesting stratum (north of 60°N latitude), where annual survival remained at about 0.87 from 1989 to 2006. Thus, the conclusion that this population continued to increase during the conservation order was largely consistent with the finding that a weighted-survival probability for midcontinent snow geese essentially did not change between the period preceding (1989–1997) and during (1998–2006) the conservation order. Consistent with high survival rates were low harvest rates, which increased from 0.024 during 1989–1997 for northern geese to only 0.027 during 1998–2006 and from 0.031 to only 0.037 for southern geese. Despite the initial increase associated with the conservation order, harvest rates declined during the conservation order for geese from both strata. We suggest that the higher harvest rate evident for southern geese was related to their earlier fall migration and thus earlier exposure to harvest pressure. Migration by more abundant northern geese was later and resulted in a higher ratio of geese to hunters. Additionally, there was more harvest of southern geese in areas north of the Canadian prairies than there was of northern geese. Total annual harvest increased due to the conservation order but failed to exceed 0.75 million adults in any year during the assessment from 1989 to 2006. Harvest of both age classes exceeded 1 million in only 2 of 9 annual harvest periods since the conservation order started. These lower-than-expected harvests of adult snow geese combined with their low harvest rates of ≤0.048 during the conservation order suggested an August population size in excess of 15 million adult snow geese since 1998. We suggest that abundance of midcontinent snow geese was seriously underestimated in the past, and that this underestimate may have contributed to an overconfidence with which suggested harvest levels could achieve a goal of reduced survival and population reduction. Overall, all 3 populations of light geese now exceed numbers present when the conservation order was initiated. We are confident that the abundance and population growth rate of midcontinent snow geese (as well as by Rosss and greater snow geese) currently exceeds the ability of existing numbers of hunters to exert harvest pressure that is necessary to impose sufficient additive mortality and thus effectively influence population growth. It remains unknown how much more or how much longer such populations can increase towards carrying capacity, which we assume to be determined by the standing crop of arctic foods that they exploit, before density dependence can measurably slow the population growth rate. Estimation of carrying capacity in the large northern nesting stratum is among the key research needs that we propose. The situation that has emerged requires a review of perspectives about impacts of midcontinent lesser snow geese in the arctic, whether initial goals behind population management are still relevant, and whether alternative options from the initial array of management tools should be exercised.

Forced copulation results in few extrapair fertilizations in Ross’s and lesser snow geese

Extrapair paternity varies from 0 to over 70% of young among various populations of birds. Comparative studies have suggested that this variation is related to nesting density, breeding synchrony and the proportion of extrapair copulations. We used minisatellite DNA fingerprinting to examine levels of extrapair paternity in Rosss geese, Chen rossi, and lesser snow geese, C. caerulescens c. (hereafter snow geese) nesting in the largest known goose colony in the world. These geese have one of the highest known percentages of extrapair copulation (46-56% of all attempted copulations), and all of these appeared to be forced. Among all successful copulations, 33 and 38% were extrapair in Rosss and snow geese, respectively. Despite the high percentage of extrapair copulations, extrapair paternity was low in both Rosss and snow geese (2-5% of young). Extrapair paternity was not related to nest density in either species. However, in snow geese, extrapair paternity was more likely to occur in nests of females that nested asynchronously, either early or late in the season. This is one of a few reported examples of a negative relationship between extrapair paternity and breeding synchrony. Extrapair young also tended to come from eggs laid later in the clutch. Although forced extrapair copulations appear to be a relatively inefficient reproductive tactic for males, they may provide a reproductive advantage for some males. Copyright 1999 The Association for the Study of Animal Behaviour.

Determination of lesser snow goose diets and winter distribution using stable isotope analysis

We were interested in demonstrating the existence of different subpopulations of wintering geese. Consequently, we measured stable-isotope ratios of carbon ( 13 C/ 12 C) and nitrogen ( 15 N/ 14 N), in lipid-extracted breast muscle of 30 lesser snow geese (Chen caerulescens caerulescens) collected in winter from 3 distinct habitat types: coastal marsh in Louisiana (n = 7), rice agriculture in Texas (n = 12), and corn agriculture in Iowa and Missouri (n = 11). We also measured concentrations of the same stable isotopes in 6 winter foods important to geese: Olneys bulrush (Scirpus olneyi) tubers and marshhay cordgrass (Spartina paterns) rhizomes from coastal marsh habitat, graminoid and non-graminoid green vegetation and non-agricultural seeds from rice prairie habitat, and corn

Neckbands, Harvest, and Survival of Ross's Geese from Canada's Central Arctic

Abstract We studied harvest of Rosss geese in North America by examining recoveries from 30,774 Rosss geese marked from 1989 to 2001 in Queen Maud Gulf Migratory Bird Sanctuary (QMGMBS), Nunavut, in Canadas central arctic. Recoveries reported by hunters in North America provided information about timing and location of harvest for 2,152 birds. Banded Rosss geese were shot and reported mostly from the U.S. (68%) and Canada (30%), but also Mexico (2%) during the study. From 1989 to 2001, there have been eastward shifts in distribution of recoveries from the Pacific Flyway to the midcontinent in the U.S., and from Alberta to Saskatchewan in Canada. Harvest in Canada was concentrated in southern Saskatchewan (85%), whereas U.S. distribution of recoveries was much broader with most recoveries from the Pacific (49%), Central (39%), and Mississippi (12%) Flyways. Continental harvest of Rosss geese began to increase in 1994 concurrent with liberalization of hunting regulations in the Canadian Prairie provinces and the Central and Mississippi Flyways, and the increased propensity of U.S. hunters, who now account for 90% of the continental harvest, to hunt outside of the U.S. Harvest from further liberalization of hunting regulations for light geese as part of the U.S. conservation order has accounted for ≤15% of continental harvest annually since 1998. Nevertheless, increased harvest of Rosss geese from the 1989 hunting season (˜8,000 birds) to the 2001 season (˜90,000 birds) best accounted for annual variation in adult survival, but was unrelated to juvenile survival. Survival of adults was >0.91 before 1994 but declined to ˜0.80 by 1998–2000 hunting seasons. Juvenile survival was relatively stable among years and ranged from 0.33 to 0.41. We found that mortality probability of adults marked with neckbands was 1.94 to 2.62 times higher than for adults without neckbands, but only 1.08 to 1.13 times higher in respective groups of juvenile Rosss geese. Thus, we advise against use of neckbands for estimation of survival in Rosss geese. The similarity and mixing of Rosss geese with snow geese in western and central North America are impediments to separate harvest management of each species. However, geographical adjustment of harvest regulations for Rosss geese in Canada is advised, with the dual objective of reducing midcontinent snow geese while conserving populations of Rosss geese on traditional winter areas in the Pacific Flyway. We recommend Rosss geese continue to be marked with legbands in QMGMBS, their principal breeding range, at least as long as liberal harvest regulations remain in place for reduction of midcontinent snow geese.

TO WINTER EAST OR WEST? HETEROGENEITY IN WINTER PHILOPATRY IN A CENTRAL-ARCTIC POPULATION OF KING EIDERS

Abstract We used banding data from King Eiders (Somateria spectabilis) at Karrak Lake, Nunavut, Canada, during 2001 and 2002 in conjunction with analysis of naturally occurring stable isotopes (13C, 15N) from feathers to connect winter and breeding areas of individuals. We also investigated the occurrence of winter philopatry among nesting females, and examined cross-seasonal effects of wintering area on subsequent breeding. Isotopic data suggested that 66–73% of this central-arctic breeding population wintered to the west (i.e., Bering Sea and North Pacific) and the remaining 24–37% wintered to the east (i.e., west Greenland, northwest Atlantic). In contrast, limited band recoveries from hunter-killed King Eiders marked at the same breeding location suggested that about 56% of individuals were shot in eastern wintering areas. These differences likely reflect stronger hunting pressures along the coast of Greenland, which result in more band recoveries for this area. Our results suggest that female King Eiders were not strongly philopatric to wintering areas among years. Individuals that wintered in western seas initiated nests 1.9 days earlier and had slightly larger clutches during early initiation relative to females that wintered in the east. Nest parasitism appeared to be biased toward earlier nesters, many of which wintered in the west. Female condition during incubation did not vary by wintering area. Our results have important implications for gene flow and for potentially associating wintering-area conditions with overall demography and individual fitness of King Eiders. ¿Pasar el Invierno en el Este o en el Oeste? Heterogeneidad en la Filopatría al Sitio de Invernada en una Población de Somateria spectabilis del Ártico Central Resumen. Para conectar las áreas de invernada con las de reproducción en la especie Somateria spectabilis, utilizamos datos de aves anilladas durante 2001 y 2002 en Karrak Lake, Nunavut, Canadá, junto con análisis de isotópos estables que se encuentran en la naturaleza y en las plumas (13C, 15N). También investigamos la existencia de filopatría al sitio de invernada entre hembras nidificantes, y examinamos los efectos del área de invernada sobre la reproducción subsiguiente. Los datos isotópicos sugirieron que el 66–73% de los individuos de esta población que nidifica en el Ártico central pasa el invierno al oeste (i.e., Mar de Bering, Pacífico Norte) y que el 24–37% restante lo hace al este (i.e., oeste de Groenlandia, noroeste del Atlántico). En contraste, los pocos anillos puestos en la misma localidad reproductiva que fueron recobrados por cazadores, mostraron que alrededor del 56% de los individuos fueron cazados en áreas de invernada ubicadas al este. Estas diferencias probablemente reflejan que las presiones de cacería son más fuertes a lo largo de la costa de Groenlandia, lo que conlleva a que se recobren más anillos en esta área. Nuestros resultados sugieren que las hembras de S. spectabilis no son fuertemente filopátricas a sus sitios de invernada entre años. Los individuos que invernaron en los mares del oeste iniciaron sus nidos 1.9 días más temprano y tuvieron nidadas ligeramente más grandes durante la etapa temprana de iniciación en comparación con las hembras que invernaron al este. El parasitismo de nidos pareció estar sesgado hacia las aves que nidificaron temprano, muchas de las cuales invernaron en el oeste. La condición de las hembras durante la incubación no varió entre áreas de invernada. Nuestros resultados tienen implicaciones importantes en términos de flujo génico y potencialmente para asociar las condiciones de las áreas de invernada con la demografía en general y con la adecuación biológica de los individuos de esta especie.

EGG SIZE, BODY SIZE, LOCOMOTION, AND FEEDING PERFORMANCE IN CAPTIVE KING EIDER DUCKLINGS

Abstract We studied the effect of egg volume and body size on swimming speed, endurance, and feeding rate in captive King Eider (Somateria spectabilis) ducklings in the Canadian arctic. Sprint speed, endurance, and feeding rate were positively related to egg size and body size. Large ducklings from large eggs performed better than small ducklings from small eggs. Ducklings that are more capable swimmers and have higher feeding rates may grow more quickly and be more effective at predator evasion. Thus, ducklings from large eggs may have a survival advantage over those from small eggs under conditions where predation and nutrition may constrain survival.

EFFECTS OF INTRINSIC AND EXTRINSIC FACTORS ON SURVIVAL OF WHITE-WINGED SCOTER (MELANITTA FUSCA DEGLANDI) DUCKLINGS

Abstract In waterfowl, offspring survival and the effects of extrinsic (i.e. weather, hatching date) and intrinsic (i.e. physical and nutritional traits of individual females and ducklings, brood sizes) factors on it are poorly understood. In 2000 and 2001, we estimated duckling and brood survival of White-winged Scoters (Melanitta fusca deglandi) at Redberry Lake, Saskatchewan, Canada, to 30 days of age to examine relationships between duckling survival and (1) hatch date, (2) initial brood size at hatch, (3) duckling size and body condition at hatch, (4) offspring sex, (5) maternal female size and body condition at hatch, and (6) weather. We estimated survival with Cormack-Jolly-Seber models, in program MARK, from observations of individually marked adult females (n = 94) and ducklings (n = 664). Most mortality (i.e. 0.80 and 0.95 for each year, respectively) occurred within six days of hatch in both years. Duckling survival probability decreased with advancing hatch date; increased with larger initial brood sizes; was higher for larger, better-conditioned ducklings; and increased with favorable weather. Brood survival decreased with advancing hatch date, increased with larger initial brood sizes, and increased with favorable weather. For 2000 and 2001, our models predict survival probabilities of ducklings (0.0061 and 0.0027, respectively) and broods (0.015 and 0.00048, respectively) that are lower than any previously reported. We suspect that intense gull (Larus spp.) predation shortly after hatch had the largest influence on duckling survival, though results also underscore the significance of intrinsic factors. Effets des Facteurs Intrinsèques et Extrinsèques sur la Survie les Jeunes de Melanitta fusca deglandi

Influence of body size and condition on harvest and survival of juvenile Canada geese

Direct recoveries for Canada goose (Branta canadensis interior) goslings from the portion of the Southern James Bay Population (SJBP) on Akimiski Island, Nunavut, Canada, have declined markedly since 1987. We suspected that poor gosling nutrition, due to limited food resources on brood-rearing areas, was causing low survival. Consequently, we measured body size and condition of 2,893 unfledged goslings during late July and early August, 1994-1996. Based on 128 recoveries of dead birds during hunting seasons and 69 recaptures during summer on Akimiski Island, we estimated the separate influences of gosling size and condition on subsequent probabilities of recovery by hunters and survival. Estimated survival probabilities were 0.025, 0.051, and 0.147, and reporting probabilities were 0.0026, 0.0051, and 0.0142 for 1994-1996, respectively. Annual variation in both probabilities was related to size and condition of goslings, which were largest and in the best condition in 1996, followed by 1995, and then 1994. Estimates of slopes suggested that relatively small increases in both body size and condition resulted in increased survival and reporting probabilities. Unlike previous waterfowl research, our results showed that the largest goslings, and those in the best condition, were the most likely to be shot. We suggest that goslings in poor condition died on Akimiski Island before they fledged. We conclude that food availability was limiting recruitment, and predict that harvest restrictions on SJBP Canada geese will not result in an increase in the segment of the population that nests on Akimiski Island.