Oxyura Jamaicensis Research Articles

EFFECTS OF A NASAL MARKER ON BEHAVIOR OF BREEDING FEMALE RUDDY DUCKS

Researchers often use nasal saddles or discs to identify individuals in studies of waterfowl ecology, but previous studies showed that these markers may have detrimental effects on reproductive behavior and success of Ruddy Ducks (Oxyura jamaicensis). To our knowledge, a non-intrusive, external marker that is easy to observe does not exist for breeding Ruddy Ducks. We evaluated effects of a modified nasal marker on behavior of female Ruddy Ducks during pre-laying, laying, and brood rearing. There was no evidence that nasal markers had an adverse influence on nesting patterns of pre-laying and laying females. During brood rearing, however, nasal-marked individuals spent more time scratching their bills and less time alert than unmarked controls. Although bill scratching was more frequent, nasal markers did not appear to influence overall reproductive behavior during nesting and or brood rearing, but we do not know whether reduced vigilance behavior affected survival of young during brood rearing. This nasal marker is a relatively non-intrusive and visible alternative for studying the short-term reproductive ecology of female Ruddy Ducks and possibly other Oxyurinae or anatids not commonly studied because of unique nasal morphologies (i.e., partially divided nasal septa and small nasal openings) which make them difficult to mark. Additionally, this marker may have application for species wintering in colder regions where nasal markers are at risk of icing. Nevertheless, we strongly suggest that researchers evaluate possible effects of these markers as part and parcel of future studies.

Low Frequency of “Double Molt” of Remiges in Ruddy Ducks Revealed by Stable Isotopes: Implications for Tracking Migratory Waterfowl

Abstract Ratios of the stable carbon (δ13C) and hydrogen (δD) isotopes in newly grown remiges of Ruddy Ducks (Oxyura jamaicensis) are influenced by the isotopic character of food types and ambient water. Systematic isotopic foodweb and water differences between coastal wintering grounds and prairie breeding grounds of Ruddy Ducks provide the basis for using isotopic analyses of feathers to trace the location and timing of molt. Anecdotal evidence, based largely on captive birds, suggests that Ruddy Ducks replace their remiges twice each year (once each on the breeding and wintering grounds), but a recent literature analysis indicates that this phenomenon is rare. Thus, we investigated the extent to which a biannual molt of the remiges occurs in the wild and at the population level. We analyzed the stable isotopes of carbon (n = 57 birds) and hydrogen (n = 50 birds) in flight feathers to estimate the prevalence of the so-called “double molt” of remiges in free-living Ruddy Ducks. Our data showed that natural populations of Ruddy Ducks express an overwhelming unimodal distribution of isotope ratios in their remiges, suggesting that they undergo a single molt at or near the breeding grounds. Only 3 to 6 of 50 birds from Manitoba showed isotopic evidence consistent with growing remiges on the wintering grounds. Feathers from Ruddy Ducks harvested during the fall in the Mississippi Flyway had isotopic profiles consistent with growth on northern freshwater breeding sites. Thus, our results confirm that the replacement of remiges twice each year by Ruddy Ducks is rare, and they suggest that this dual stable-isotope technique can be used to infer general molting origins of North American waterfowl.

LOW FREQUENCY OF “DOUBLE MOLT” OF REMIGES IN RUDDY DUCKS REVEALED BY STABLE ISOTOPES: IMPLICATIONS FOR TRACKING MIGRATORY WATERFOWL

Ratios of the stable carbon (d13C) and hydrogen (dD) isotopes in newly grown remiges of Ruddy Ducks (Oxyura jamaicensis) are influenced by the isotopic character of food types and ambient water. Systematic isotopic foodweb and water differences between coastal wintering grounds and prairie breeding grounds of Ruddy Ducks provide the basis for using isotopic analyses of feathers to trace the location and timing of molt. Anecdotal evidence, based largely on captive birds, suggests that Ruddy Ducks replace their remiges twice each year (once each on the breeding and wintering grounds), but a recent literature analysis indicates that this phenomenon is rare. Thus, we investigated the extent to which a biannual molt of the remiges occurs in the wild and at the population level. We analyzed the stable isotopes of carbon (n 5 57 birds) and hydrogen (n 5 50 birds) in flight feathers to estimate the prevalence of the so-called ''double molt'' of remiges in free-living Ruddy Ducks. Our data showed that natural populations of Ruddy Ducks express an overwhelming unimodal distribution of isotope ratios in their remiges, suggesting that they undergo a single molt at or near the breeding grounds. Only 3 to 6 of 50 birds from Manitoba showed isotopic evi- dence consistent with growing remiges on the wintering grounds. Feathers from Ruddy Ducks harvested during the fall in the Mississippi Flyway had isotopic profiles consistent with growth on northern freshwater breeding sites. Thus, our results confirm that the re- placement of remiges twice each year by Ruddy Ducks is rare, and they suggest that this dual stable-isotope technique can be used to infer general molting origins of North American waterfowl. Received 6 October 1998, accepted 26 May 1999.

Ruddy Duck Nesting Success: Do Nest Characteristics Deter Nest Predation?

It has been hypothesized that proximity to edges, timing of nesting, nest concealment or inaccessibility, working singly or in concert, may explain variable nesting success of birds, but results have been mixed. I tested these hypotheses by determining fates and measuring nest-site features of 233 Ruddy Duck (Oxyura jamaicensis) nests near Minnedosa, Manitoba, Canada, during summers of 1994-1996. Mayfield nesting success averaged 41%. Discriminant function analysis was unable to segregate successful and destroyed nests. Results suggest that nesting success for this population of Ruddy Ducks is unpredictable, probably because a diversity of predators precluded choice of safe nest sites.

Body Size, Nest Initiation Date, and Egg Production in Ruddy Ducks

Female Ruddy Ducks (Oxyura jamaicensis) produce the largest eggs, relative to body size, of all waterfowl (Lack 1968). Energy in one of their eggs is equivalent to 322% of daily basal metabolic rate (Alisauskas and Ankney 1992), the highest of all Anatidae. Furthermore, Ruddy Ducks lay one egg per day (Siegfried 1976). Female Ruddy Ducks rely on both endogenous and exogenous nutrients for egg production. On average, 49% of the lipid, 41% of the protein, and 16% of the minerals required for egg production are supplied by stored reserves in Ruddy Ducks (Alisauskas and Ankney 1994). These authors also reported that the size of lipid, mineral, and protein reserves was positively related to body size in their sample of breeding females. Thus, we predicted that larger female Ruddy Ducks would lay larger clutches. Also, because birds in good condition (i.e. with larger reserves) may initiate nesting earlier than those in poorer condition (Reynolds 1972, Scott and Birkhead 1983), we also predicted that larger females are able to attain good condition and would initiate nesting earlier than would smaller females. Within species, variation in egg mass among females is high in waterfowl (Ankney and Alisauskas 1992), but few studies have attempted to determine the source of this variation. In Lesser Snow Geese (Chen c. caerulescens), about 60% of among-female variation in egg mass is heritable (Lessells et al. 1989). Such an estimate may be inflated if larger females lay larger eggs and if body size also is heritable (see Alisauskas and Ankney 1992). Indeed, egg mass is positively related to body size in Lesser Snow Geese (Newell 1988) and Northern Pintails (Anas acuta; Flint and Grand 1996). Thus, we also investigated whether egg size of female Ruddy Ducks was related to body size. Methods.-This study was conducted in 1994 in southwestern Manitoba near Minnedosa (50011'N, 90?42'W). The rolling knob-and-kettle landscape is scattered with wetlands ranging in size from 10 m2 to 4 ha (Evans et al. 1952, Dzubin 1961). Emergent vegetation in the region includes cattail (Typha spp.),

Association of mercury and selenium with altered glutathione metabolism and oxidative stress in diving ducks from the San Francisco bay region, USA

AbstractAult male greater scaup (Aythya marila), surf scoters (Melanitta perspicillata), and ruddy ducks (Oxyurajamaicensis) were collected from Suisun Bay and coastal Tomales Bay in the greater San Francisco Bay area to assess exposure to inorganic contaminants. Hepatic Se concentrations were highest in greater scaup (geometric mean = 67 ppm dry weight) and surf scoters (119 ppm) in Suisun Bay, whereas hepatic Hg was highest (19 ppm) in greater scaup and surf scoters from Tomales Bay. Hepatic Se and Hg were lower in ruddy ducks and did not differ between locations. Hepatic supernatants were assayed for enzymes related to glutathione metabolism and antioxidant activity, including glucose‐6‐phosphate dehydrogenase (G‐6‐PDH), glutathione peroxidase (GSH peroxidase), glutathione reductase (GSSG reductase), and glutathione‐S‐transferase (GSH transferase). Glutathione peroxidase activity was higher in surf scoters and ruddy ducks, and G‐6‐PDH was higher in greater scaup and surf scoters from Suisun Bay than Tomales Bay. Glutathione reductase (GSSG) was higher in SS from Suisun Bay. The ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) was greater in all species from Tomales Bay. The following significant relationships were found in one or more species with increasing hepatic Hg concentration: lower body, liver, and heart weights; decreased hepatic GSH concentration and G‐6‐PDH and GSH peroxidase activities; increased ratio of GSSG to GSH; and increased GSSG reductase activity. With increasing hepatic Se concentration, GSH peroxidase increased, but GSH decreased. It is concluded that measurement of associated enzymes in conjunction with thiol status may be a useful bioindicator to discriminate between Hg and Se effects. Concentrations of Hg and Se and the above variables affected have been associated with adverse effects on reproduction and neurological function in experimental studies with mallards.

ASSOCIATION OF MERCURY AND SELENIUM WITH ALTERED GLUTATHIONE METABOLISM AND OXIDATIVE STRESS IN DIVING DUCKS FROM THE SAN FRANCISCO BAY REGION, USA

Ault male greater scaup (Aythya marila), surf scoters (Melanitta perspicillata), and ruddy ducks (Oxyurajamaicensis) were collected from Suisun Bay and coastal Tomales Bay in the greater San Francisco Bay area to assess exposure to inorganic contaminants. Hepatic Se concentrations were highest in greater scaup (geometric mean = 67 ppm dry weight) and surf scoters (119 ppm) in Suisun Bay, whereas hepatic Hg was highest (19 ppm) in greater scaup and surf scoters from Tomales Bay. Hepatic Se and Hg were lower in ruddy ducks and did not differ between locations. Hepatic supernatants were assayed for enzymes related to glutathione metabolism and antioxidant activity, including glucose-6-phosphate dehydrogenase (G-6-PDH), glutathione peroxidase (GSH peroxidase), glutathione reductase (GSSG reductase), and glutathione-S-transferase (GSH transferase). Glutathione peroxidase activity was higher in surf scoters and ruddy ducks, and G-6-PDH was higher in greater scaup and surf scoters from Suisun Bay than Tomales Bay. Glutathione reductase (GSSG) was higher in SS from Suisun Bay. The ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) was greater in all species from Tomales Bay. The following significant relationships were found in one or more species with increasing hepatic Hg concentration: lower body, liver, and heart weights; decreased hepatic GSH concentration and G-6-PDH and GSH peroxidase activities; increased ratio of GSSG to GSH; and increased GSSG reductase activity. With increasing hepatic Se concentration, GSH peroxidase increased, but GSH decreased. It is concluded that measurement of associated enzymes in conjunction with thiol status may be a useful bioindicator to discriminate between Hg and Se effects. Concentrations of Hg and Se and the above variables affected have been associated with adverse effects on reproduction and neurological function in experimental studies with mallards.

Avian Habitat Selection and Prairie Wetland Dynamics: A 10-Year Experiment

Northern prairie wetlands play a vital role in the life cycle of a wide array of bird species. Prairie wetlands used by birds span the entire range from shallow ephemeral ponds inundated for short periods each spring to large permanent water bodies that seldom, if ever, go dry. The objective of this study was to determine the response of blackbirds, waterfowl, and American Coots to changes in habitat structure induced by water level fluctuations in prairie wetlands. The study was conducted on a series of experimental marshes within the Delta Marsh in southern Manitoba, Canada. Water levels were adjusted following a predetermined schedule to simulate the wet–dry cycle of prairie marshes. Aerial photographs were taken annually, and habitats were characterized using Geographic Information System (GIS) techniques. Weekly avian censuses were related to habitat features using Principal Components Analysis (PCA) procedures. Yellow-headed Blackbirds selected shallowly flooded habitats with a mixture of open water and emergent vegetation, while Red-winged Blackbirds were found in shallower areas with dense vegetation. Coot habitat was consistent over the seasons. They preferred deep-water habitats with interspersed vegetation. As a group, dabbling ducks were generally found in hemi-marsh conditions (equal amounts of cover and water in an interspersed pattern) throughout much of the year. Some species moved to deeper, more open habitats during the fall season. As a group, diving ducks chose areas with deeper water and less vegetation than dabbling ducks. However, there was considerable variation among diving duck species, with Canvasbacks using hemi-marsh sites in spring, and Ruddy Ducks and Lesser Scaup using the most open sites found on the study areas. The wet–dry cycle characteristic of prairie marshes presents a wide array of habitat conditions for avian species. Although hemi-marsh conditions during the cycle result in maximum use for a large number of species, they do not meet the requirements of all species in all seasons. Conservation programs should include wetland complexes of varying water depth and flooding duration to ensure the widest array of habitat types for avian species.

Ruddy Ducks and Other Stifftails: Their Behavior and Biology

Ruddy Ducks and Other Stifftails: Their Behavior and Biology

RECENT ORNITHOLOGICAL PUBLICATIONS

BENTON, T.G & SPENCER, T. 1995. The Pitcairn Islands. Biogeography, ecology and prehistory.CHEKE, R.A. & WALSH, J.F. 1996. The Birds of Togo. BOU ChecklistDAAN, P., NORMAN. I. & Rimx, P. (eds). 1995. The Penguins: Ecology and management.DEWAK, S.M. & SHAWYER. C.R. 1996. Boxes. Baskets and Platforms: Artificial nest sites for owls and other birds of prey.DINGLE. H. 1996. Migration: The biology of life on the move.FEBUCCIA, A. 1996. The Origin and Evolution of Birds.HOLMES, D.A. L PHILLIPPS, K. 1996. The Birds of Sulawesi.JOHNSGARD. P.A. & CARBONELL, M. 1996. Ruddy Ducks and Other Stifftails: Their behavior and biology.LANNER. R.M. 1966. Made for Each Other: A symbiosis of birds and pines.Meyburg. B.‐U. & CHANCELLOR, R.D. (eds) 1996. Eagle Studies.PINOWSKI, J., KAVANAGH, B.P. & PINOWSKA, B. (eds). 1995. Nestling Mortality of Granivorous Birds due to Microrganisms and Toxic Substances: Synthesis.POOLE, A.F & GILL, EB. (eds). 1995. The Birds of North America: Life histories for the 21st century. Nos 161–200. Washington, D.C.: The American Ornithologists' Union and The Academy of Natural Sciences of Philadelphia.PORTER, R.F., CHRISTENSEN, S. & SCHIERMACKER‐HANSEN. P. 1996. Field Guide to the Birds of the Middle East.SCHELHAS, J. & GREENBERG, R. (eds). 1996. Forest Patches in Tropical Landscapes.SHURTLEFF, L.L. & SAVAGE, C. 1996. The Wood Duck and the Mandarin: The northern wood ducks.SKUTCH, A.F. 1996. The Minds of Birds.TULLY, T.N., JR. & SHANE. S.M. (eds). 1996. Ratite Management, Medicine and Surgery.

Relationship between waterfowl nutrition and condition on agricultural drainwater ponds in the Tulare Basin, California: Waterfowl body composition

We examined carcass composition and proximate food composition of ruddy ducks (Oxyura jamaicensis), northern shovelers (Anas clypeata), and northern pintails (Anas acuta) wintering on agricultural drainwater ponds in California during 1983–84. Lipids varied seasonally in northern shovelers and northern pintails. Protein did not fluctuate except in ruddy ducks whose protein mass increased over winter, suggesting that some protein was catabolized prior to arrival on wintering areas or that a buildup of protein occurred prior to spring migration. Waterfowl diets varied among species and time, but the nutritional composition of the diets was relatively stable. Ruddy ducks and shovelers consumed mostly animal foods rich in protein (53–60%) and low in Nitrogen Free Extract (NFE)(1–7%). Pintail diets contained more NFE (23–38%) and less protein (14–38%) because of greater consumption of plant foods. Nutritional composition of pintail diets varied with lower protein consumption occurring from November through January.

An observation of renesting by a Ruddy Duck, Oxyura jamaicensis

An observation of renesting by a Ruddy Duck, Oxyura jamaicensis

Ruddy Ducks and Other Stifftails: Their Behavior and Biology, by P. A. Johnsgard and Montserrat Carbonell [Review

Ruddy Ducks and Other Stifftails: Their Behavior and Biology, by P. A. Johnsgard and Montserrat Carbonell [Review

Ruddy ducks & other stifftails: their behavior and biology

Ruddy ducks & other stifftails: their behavior and biology

Ruddy Ducks and other stifftails. Their behavior and biology.

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Response of ducks to glyphosate-induced habitat alterations in wetlands

The effects of glyphosate herbicide-induced changes in wetland emergent vegetation (largely cattails,Typha spp.) on densities of ducks (Anatinae) were assessed in northeastern North Dakota. In 1990 and 1991, 17 cattail-dominated wetlands were randomly assigned to 0% (reference wetlands), 50%, 70%, or 90% areal spray coverages with glyphosate herbicide. Densities of green-winged teal (Anas crecca), bluewinged teal (Anas discors), gadwalls (Anas strepera), and ruddy ducks (Oxyura jamaicensis) were similar among treatments during both post-treatment years (P≥0.1). One year post-treatment, mallard (Anas platyrhynchos) and northern pintail (Anas acuta) abundances did not differ among treatments (P≥0.1), whereas two years post-treatment their abundances were greater in the sprayed wetlands than in the reference wetlands (P≤0.1). Densities of northern shovelers (Anas clypeata) and redheads (Aythya americana) differed among treatments in both post-treatment years, with the 50% sprayed wetlands harboring more ducks than did the other three treatments. Percent coverage and hectares of open water were positively correlated with numbers of diving ducks (Aythyini and Oxyurini) (P≤0.1). Dabbling duck (Anatini and Cairinini) numbers correlated positively with hectares of open water and dead vegetation, whereas their numbers were negatively correlated with percent coverage of live vegetation (P≤0.1). Results of this study suggest that numbers of ducks were positively influenced by creating a mosaic of open water, live vegetation, and dead vegetation with glyphosate herbicide.

Habitat Use and Nest Success of Overwater Nesting Ducks in Westcentral Minnesota

Where several duck species coexist, managers need knowledge of species-specific similarities and differences in patterns of nest habitat use and nest success. We searched overwater habitat (i.e., rooted stands of cattail [Typha spp.], bulrush [Scirpus spp.], or phragmites [Phragmites australis], floating mats of sedge [Carex spp.] and/or cattail, wet sedge/grass [Poaceae] meadows, and willow [Salix spp.] swamps) in westcentral Minnesota and located 155 overwater nests of 5 duck species. Nests were in wetlands of 0.2 to 32.0 ha that were 20 to 100% covered by overwater habitat. A canonical discriminant function analysis clarified some similarities and differences among the 5 species in their nest habitat use. Some individuals of each species, but especially redheads (Aythya americana) and ruddy ducks (Oxyura jamaicensis), nested in relatively more open, larger, deeper type 4 wetlands with cover near nests dominated by cattails and lacking sedges. Most mallards (Anas platyrhynchos) and ring-necked ducks (Aythya collaris) nested in smaller, shallower type 2 and 3 wetlands which had a high proportion of the basin covered by overwater habitat and at sites where overwater vegetation, particularly sedges, was dense and nests were well screened. Mallards and ring-necked ducks were the only species nesting in type 2 wetlands or on floating sedge mats and except for 2 canvasback (Aythya valisineria) nests, were the only species to use floating cattail mats as nest sites. Canvasbacks typically nested in type 3 and 4 wetlands of intermediate size, depth, and proportion of basin covered by overwater habitat. Their nests were at sites of moderate vegetation density and were less well screened by vegetation than those of the other species. Mallards had lower nest success (3.8%) than ring-necked ducks (34.1%) or all diving ducks combined (26.5%) (α = 0.10). Of 105 nests that failed to hatch, 74.3% were depredated while 13.3% were flooded. Multiple logistic regression analyses indicated that none of the 11 habitat characteristics measured at our nest sites predicted whether a nest would hatch or be depredated (all P > 0.20).

Nutrition of Breeding Female Ruddy Ducks: The Role of Nutrient Reserves

We determined fat, protein, and mineral content of somatic tissue, and estimated amounts of these nutrients committed to eggs by Ruddy Ducks (Oxyurajamaicensis) nesting in southern Manitoba in 1988. Seasonal nutrient dynamics differed between breeding and nonbreeding females. Nonbreeders had less fat and protein reserves than did breeders early in the nesting season, but these then increased and subsequently declined, whereas nutrient reserves of breeders declined linearly with date from the outset of our study. Onset of breeding was related to a nutrient reserve threshold (early RFG [rapid follicle growth] ducks had 22.7 g more fat and 5.1 g more protein than did non-RFG ducks). Adults showed greater propensity to initiate breeding (73% of breeding population) than did yearlings (68% of nonbreeding population), and we relate this to greater fat and protein reserves of adults. Adult breeders had more fat and protein reserves than did yearlings at every stage in the breeding cycle but no age-related differences in use of fat, protein or mineral reserves for clutch formation were found. When controlling for date effects, fat reserves declined (b = -0.49) as fat was committed to eggs. Early nesters initiated and ended egg laying with significantly more fat compared to late nesters, although rate of fat use was not different. Protein and mineral reserves were used for clutch formation by early nesters (b = -0.24 and -0.08, respectively), but not by late nesters. Among females nearing end of laying, number of developing follicles was related to mineral, but not fat or protein reserves, indicating that mineral reserves were a proximate factor constraining clutch size. Our findings confirm that, for Ruddy Ducks, somatic tissues are important sources of nutrients for clutch formation, and that clutch size is directly related to mineral reserves. Of importance to lifetime reproduction, and thus fitness, is our finding that minimum levels ofnutrient reserves appear critical for initiation of breeding by female Ruddy Ducks.

Costs and Rates of Egg Formation in Ruddy Ducks

Costs and Rates of Egg Formation in Ruddy Ducks

Body composition dynamics of ruddy ducks during wing moult

A method was developed for indexing moulting costs in waterfowl based on intensity of moult and proportional mass of feathers in seven feather regions (ADJMOLT). This method was then applied to an examination of relations between moulting costs and size-adjusted body mass and composition of postbreeding male and female ruddy ducks (Oxyura jamaicensis) collected in southwestern Manitoba, 30 July – 24 August 1985. Moderate to heavy moult (25 to > 50% of moulting feathers) was recorded in all feather regions. The intensity of down moult was greater in males than in females, but no differences between sexes in moult score by contour feather region, overall mean moult score, or ADJMOLT were detected. Relations between ADJMOLT and body fat (FAT), liver protein (LIVER), and size-adjusted body mass (ADJMASS), body protein (ADJPROT), and leg and breast muscle protein (ADJLEG and ADJBR, respectively) were not influenced by sex, but there was a sex effect on the relation of ADJMOLT to gizzard mass (GIZZWT). ADJPROT and ADJBR were negatively associated with ADJMOLT, whereas female GIZZWT was positively related to ADJMOLT. ADJMASS, ADJLEG, FAT, and LIVER were unrelated to ADJMOLT. Female ruddy ducks were structurally smaller and had less ADJMASS, ADJPROT, ADJLEG, and FAT than males, but there were no sex-related differences in ADJBR. I found no evidence of nutritional stress in post-breeding ruddy ducks, but argue that stress associated with moult in waterfowl is most likely to occur in females, especially small-bodied species that are primarily herbivorous.