Interspecific differences in bill and tongue morphology among diving ducks (Aythya spp., Oxyura jamaicensis)

1989 ◽  
Vol 67 (11) ◽  
pp. 2694-2699 ◽  
Author(s):  
Barbara A. Lagerquist ◽  
C. Davison Ankney
Keyword(s):  
Morphological Characters ◽  
Diving Ducks ◽  
Size And Shape ◽  
Interspecific Differences ◽  
Lesser Scaup ◽  
Aythya Valisineria ◽  
Bill Morphology ◽  
Intermediate Size ◽  
Ruddy Ducks ◽  
Oxyura Jamaicensis

Twelve morphological characters of the bill and tongue were measured in six species of diving ducks (Aythya and Oxyura spp.). We used multivariate analyses to describe interspecific differences in morphology and related these differences to published information about food habits and feeding behavior of the six species. Canvasbacks (Aythya valisineria) have long, narrow, deep bills that are well suited to probing and grasping plant tubers from the substrate. Greater (A. marila) and Lesser Scaup (A. qffinis) and Ruddy Ducks (Oxyura jamaicensis) have short, wide, shallow bills suited to straining food items. Lesser Scaup and Ruddy Ducks have the greatest lamellar density and this enables them to strain very small plant and animal material. Redheads (A. americana) and Ring-necked Ducks (A. collaris) have bills of intermediate size and shape that are suited to straining seeds and grazing leafy parts of plants. Lesser and Greater Scaup, on the basis of bill morphology, are more similar to Ruddy Ducks than they are to other Aythya species. Overall, bill size and shape were more important in distinguishing the six species than were lamellar density or tongue characteristics.

Variation in digestive organ size among five species of diving ducks (Aythya spp.)

1985 ◽  
Vol 63 (10) ◽  
pp. 2339-2342 ◽  
Author(s):  
F. Patrick Kehoe ◽  
C. Davison Ankney
Keyword(s):  
Body Weight ◽  
Diving Ducks ◽  
Aythya Affinis ◽  
Interspecific Differences ◽  
Lesser Scaup ◽  
Aythya Americana ◽  
Aythya Valisineria ◽  
Intestine Length ◽  
Morphological Differences ◽  
Interspecific Comparisons

Ceca length, small intestine length, and gizzard weight were measured for individuals of five species of diving ducks collected at Long Point Bay, Lake Erie, and Mitchell's Bay, Lake St. Clair, Ontario, in the falls of 1982 and 1983. The five species were Lesser Scaup (Aythya affinis, N = 84), Ring-necked Duck (Aythya collaris, N = 57), Greater Scaup (Aythya marila, N = 54), Redhead (Aythya americana, N = 58), and Canvasback (Aythya valisineria, N = 112). The diets of these species reportedly differ in diversity as well as in amount of fibre, and interspecific differences in gut morphology, not explained by differences in body weight, were accounted for by general differences in diet. Canvasbacks, although the heaviest species, had the shortest ceca, short intestines and light gizzards, presumably because their diet contains the least fibre. Conversely, the relatively small-bodied scaup species had the longest small intestines, likely because of their diverse diets which include animal and plant material. Our results show that morphological differences in waterfowl guts reflect dietary differences at a particular time and location and also illustrate the importance of adjusting gut measurements to body weight before making interspecific comparisons.

Further Observations on the Morphology of Heterodera schachtii, with Remarks on the Bionomics of a strain attacking Mangolds in Britain

1929 ◽  
Vol 7 (3) ◽  
pp. 119-140 ◽  
Author(s):  
Marjorie J. Triffitt
Keyword(s):  
Sugar Beet ◽  
Developmental Stages ◽  
Morphological Characters ◽  
Heterodera Schachtii ◽  
Adult Males ◽  
Morphological Variations ◽  
Size And Shape ◽  
Morphological Studies ◽  
Comparative Survey

In a previous publication the morphological characters of a strain of H. schachtii specialised on the potato in Lincolnshire were discussed. The size and shape of the brown cysts, size of the eggs and first stage larvæ and the general characters of the adult males of this strain were compared with those of a strain attacking potatoes in Rostock, Mecklenburg, for which the specific name H. rostochiensis was suggested by Wollenweber 1923.Considerable dimensional variations were found to exist in the Lincolnshire strain, and a study of the literature on the morphological characters of H. schachtii specialised on sugar-beet and oats, showed equally wide divergencies between the findings of different workers. A certain amount of preserved material of infected roots of beet and oats being available to the writer, as many developmental stages as possible were extracted from these, on which similar morphological studies were carried out. Thus a fairly complete comparative survey of H. schachtii specialised on beet, oats and potatoes was completed, and the morphological variations between the strains were found to be insufficient to justify the separation of the strain specialised on potato from those on beet and oats. The name H. rostochicnsis was, therefore, deemed a synonym for H. schachtii.

Comparative migration, growth and development of Typhlocoelum cucumerinum sisowi in dabbling ducks and Typhlocoelum cucumerinum cucumerinum in diving ducks

Parasitology ◽  
1982 ◽  
Vol 84 (2) ◽  
pp. 333-350 ◽  
Author(s):  
Marilyn E. Scott ◽  
M. E. Rau ◽  
J. D. McLaughlin
Keyword(s):  
Life Cycle ◽  
Life Span ◽  
Definitive Host ◽  
Host Species ◽  
Growth And Development ◽  
Abdominal Cavity ◽  
Dabbling Ducks ◽  
Diving Ducks ◽  
Air Sacs ◽  
Aythya Valisineria

SUMMARYExperimental infections of mallards (Anas platyrhynchos L.) with Typhlocoelum cucumerinum sisowi (Skrjabin, 1913) and of canvasbacks (Aythya valisineria (Wilson)) with Typhlocoelum cucumerinum cucumerinum (Rudolphi, 1809) revealed significant differences in various parameters of the life-cycle in the definitive host. Both T. c. sisowi and T. c. cucumerinum migrate to the trachea via the abdominal cavity, air sacs and lungs, although T. c. cucumerinum migrate more quickly and more synchronously than T. c. sisowi. Typhlocoelum c. sisowi has a shorter expected life-span than T. c. cucumerinum but grows and reaches maturity more quickly than T. c. cucumerinum. Evidence suggests that T. c. cucumerinum has a higher fecundity than T. c. sisowi. These differences in the patterns of migration, growth and development are related not only to differences between the two host species but also to differences intrinsic to the parasites, and serve to provide biological support for considering them as separate sub-species.

Circadian rhythms in diving behavior and ventilatory response to asphyxia in canvasback ducks

1998 ◽  
Vol 274 (3) ◽  
pp. R686-R693 ◽  
Author(s):  
Melanie Woodin ◽  
Richard Stephenson
Keyword(s):  
Control Systems ◽  
Ventilatory Response ◽  
Behavioral Control ◽  
Feeding Activity ◽  
Diving Behavior ◽  
Diving Ducks ◽  
Timing System ◽  
Aythya Valisineria ◽  
Circadian Timing System ◽  
Respiratory Responses

Underwater feeding behavior was measured in 10 captive canvasback ducks ( Aythya valisineria) for 12 days under a 12:12-h light-dark photoperiod. Feeding activity exhibited a daily rhythm, with 76% of dives occurring at night. In separate experiments on six of these ducks, a circadian rhythm was observed in the duration of voluntary dives. Dives at night (14.7 ± 0.7 s) were significantly longer than those during the day (10.7 ± 0.7 s). These day-night differences in diving behavior were accompanied by day-night differences in respiratory responses to progressive asphyxia. In the same six ducks, ventilation increased exponentially as a function of inspired CO2 concentration during rebreathing in a closed-circuit barometric plethysmograph. The exponential rate constant for inspired ventilation was significantly smaller at night (0.23 ± 0.02) than during the day (0.26 ± 0.01). We suggest that intermittent apneic exercise is facilitated by reduced respiratory chemosensitivity and that the respiratory and behavioral control systems are synchronized by the circadian timing system in diving ducks.

scholarly journals Winter Waterbird Community Composition and Use at Created Wetlands in West Virginia, USA

Scientifica ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Hannah L. Clipp ◽  
Michael L. Peters ◽  
James T. Anderson
Keyword(s):  
West Virginia ◽  
The United States ◽  
Created Wetlands ◽  
Age Difference ◽  
Canada Geese ◽  
Diving Ducks ◽  
Aythya Affinis ◽  
Lesser Scaup ◽  
Vegetation Water ◽  
Anas Strepera

Information on nonbreeding waterbirds using created wetlands in the Central Appalachian region of the United States is limited. We compared waterbird communities of two managed wetlands, created in 2013 and 2001, in West Virginia. We observed 27 species of waterbirds. Species richness and diversity were generally similar between the wetlands, but species composition and use differed.Branta canadensis(Canada Geese),Anas strepera(Gadwall),Bucephala albeola(Buffleheads),Aythya affinis(Lesser Scaup), andAythya collaris(Ring-Necked Ducks) used the older wetland most frequently. Disparities in species use were the highest in March. The older wetland differed from the younger in supporting species such as diving ducks, possibly due to differences in size, vegetation, water depth, and microtopography. However, the ability to provide habitat for waterbirds during the winter was determined to be comparable between wetlands, despite their age difference.

Spatial structure of a diving duck (Aythya, Oxyura) guild: how does habitat structure and competition influence diving duck habitat use within northern prairie wetlands?

2006 ◽  
Vol 84 (9) ◽  
pp. 1358-1367 ◽  
Author(s):  
S.M. Torrence ◽  
M.G. Butler
Keyword(s):  
Sympatric Species ◽  
Benthic Invertebrate ◽  
Organic Content ◽  
Current Evidence ◽  
Similar Species ◽  
Prairie Wetlands ◽  
Diving Duck ◽  
Diving Ducks ◽  
Aythya Valisineria ◽  
Coexistence Mechanisms

What circumstances allow the coexistence of similar species is a common but complex question in community ecology. It is often assumed that sympatric species within the same guild must employ some mechanism of niche diversification to coexist. Diving duck (Anatidae: Aythya Boie, 1822 and Oxyura Bonaparte, 1828) competition is poorly understood and current evidence of coexistence mechanisms is contradictory. In the spring and summer of 2001 and 2002, we tested whether diving ducks foraging within prairie potholes segregate by depth to avoid competition. We sought to explain any segregation by sampling sediment particle size, compactness, and organic content; submergent vegetation; and benthic invertebrate densities in the foraging locations of each species. Our study was conducted at the wetland scale in southwestern Manitoba, Canada. We found that Redheads ( Aythya americana (Eyton, 1838)), Ruddy Ducks ( Oxyura jamaicensis (J.F. Gmelin, 1789)), Canvasbacks ( Aythya valisineria (Wilson, 1814)), and Ring-necked Ducks ( Aythya collaris (Donovan, 1809)) foraged most often at shallow depths (50–100 cm), while Lesser Scaups ( Aythya affinis (Eyton, 1838)) foraged at shallow to intermediate depths (50–150 cm). Thus, most divers did not segregate by depth. These results conflict with an earlier study that reported diving ducks segregated by depth to avoid competition. Diving ducks likely forage where prey abundance is greatest relative to the cost of diving to obtain that prey.

Bryobia arborea n. sp. and Morphological Characters Distinguishing It from B. praetiosa Koch (Acarina: Tetranychidae)

1957 ◽  
Vol 89 (11) ◽  
pp. 485-490 ◽  
Author(s):  
C. V. G. Morgan ◽  
N. H. Anderson
Keyword(s):  
New Species ◽  
Body Size ◽  
Morphological Characters ◽  
Valid Species ◽  
Species Number ◽  
Modern Trend ◽  
Immature Stages ◽  
Type Specimens ◽  
Size And Shape

The clover, or brown, mite, Bryobia praetiosa Koch, was described in 1836 from specimens collected an shrubbery in Germany. The systematics of the species is complex and confusing. By 1838, Koch had described four species in the genus Bryobia but he preserved no type specimens and his descriptions do not agree with his illustrations (7, 12). Subsequent workers either placed Koch's species in synonomy nor described new species. Two species, speciosa Koch and ribis Thomas, have created the most controversv. B. speciosa was accepted as valid by Koch, Berlese, Canestrini and Fanzago, ind Oudemans, but rejected by von Hanstein and Trägårdh (2, 12). The gooseberry mite, B. ribis, was recognized as a valid species by Thomas and von Hanstein but Oudemans and Trägårdh placed it in synonomy with B. praetiosa (12). Further confusion was caused by the descriptions of additional new species of Bryobia and by descriptions of immature stages of B. praetiosa (8). The following taxonomic characters used by early acarologists in describing species of Bryobia have since been considered too variable for distinguishing species: number of femoral and tarsal hairs on the foreleg, body size, concavity of dorsum, and size and shape of cephalothoracic plate (7, 8, 12). Consequently, taxonomists have been at a loss to interpret Koch's original descriptions and subsequent redescriptions became inevitable. Because of the lack of morphological distinctions the modern trend has been to group all previously proposed species into one valid species (7, 8). As a result, 20 synonyms are now recognized for B. praetiosa (8).

scholarly journals Consequences of Egg Size for Offspring Survival: A Cross-Fostering Experiment in Ruddy Ducks (Oxyura Jamaicensis)

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 384-393
Author(s):  
Jeffrey T. Pelayo ◽  
Robert G. Clark
Keyword(s):  
Egg Size ◽  
Hatching Date ◽  
Offspring Survival ◽  
Maternal Influences ◽  
Size Dependent ◽  
Duck Species ◽  
In The Wild ◽  
Ruddy Ducks ◽  
Cross Fostering ◽  
Oxyura Jamaicensis

Abstract In birds, large egg size often enhances subsequent offspring survival, but most previous studies have been unable to separate effects of egg size from other maternal influences. Therefore, we first evaluated variance components of egg size both within and among individual female Ruddy Ducks (Oxyura jamaicensis), and then tested for egg-size-dependent survival of ducklings in the wild by switching complete broods among females. Forty broods consisting of 244 individually color-marked, day-old ducklings of known egg size were given to foster mothers, and survival was monitored to one month. Analysis of mark–resighting data showed that offspring survival was best modeled to include effects of egg size and hatching date; survival probability increased with egg size, but declined with advancing hatching date. Duckling body mass, body size, and body condition measured at hatching were positively correlated with egg size. Unlike most other duck species, and for reasons that are speculative, egg sizes varied within clutches nearly as much as they did among clutches. Selective mortality of small egg phenotypes during the first weeks after hatching likely is the result of smaller duckling size and reduced energy reserves, characteristics that must be particularly unfavorable in adverse environments.

Typification and an emended description of Astragalus moussavii (Fabaceae, Papilionoideae)

Phytotaxa ◽  
2020 ◽  
Vol 441 (1) ◽  
pp. 60-68 ◽  
Author(s):  
FARROKH GHAHREMANINEJAD ◽  
ATIYE NEJAD FALATOURY ◽  
FARSHID MEMARIANI
Keyword(s):  
Conservation Status ◽  
Morphological Characters ◽  
Terminal Leaflet ◽  
Field Observations ◽  
Size And Shape ◽  
Emended Description

Type materials of Astragalus moussavii (Fabaceae) are designated as a lectotype and four isolectotypes. An epitype for the species is designated here too. An emended description of A. moussavii is provided with illustrations and information on several morphological characters not indicated in the protologue, including the size and shape of the terminal leaflet, petals characteristics, fruit and seed features. Based on field observations, a brief description of the habitat and data on ecology and biogeography of the species are provided and its conservation status is evaluated.

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