Predation rates, timing, and predator composition for Scoters (Melanitta spp.) in marine habitats

2012 ◽  
Vol 90 (1) ◽  
pp. 42-50 ◽  
Author(s):  
Eric M. Anderson ◽  
Daniel Esler ◽  
W. Sean Boyd ◽  
Joseph R. Evenson ◽  
David R. Nysewander ◽  
...  
Keyword(s):  
Pacific Coast ◽  
Haliaeetus Leucocephalus ◽  
Bald Eagles ◽  
Southeast Alaska ◽  
Sea Ducks ◽  
Marine Habitats ◽  
Melanitta Perspicillata ◽  
The Pacific ◽  
Declining Populations

Studies of declining populations of sea ducks have focused mainly on bottom–up processes with little emphasis on the role of predation. We identified 11 potential predators of White-winged Scoters ( Melanitta fusca (L., 1758)) and Surf Scoters ( Melanitta perspicillata (L., 1758)) in North American marine habitats. However, of 596 Scoters marked with VHF transmitters along the Pacific coast, mortalities were recovered in association with just two identifiable categories of predators: in southeast Alaska recoveries occurred mainly near mustelid feeding areas, while those in southern British Columbia and Washington occurred mainly near feeding areas of Bald Eagles ( Haliaeetus leucocephalus (L., 1766)). Determining whether marked Scoters had been depredated versus scavenged was often not possible, but mortalities occurred more frequently during winter than during wing molt (13.1% versus 0.7% of both species combined, excluding Scoters that died within a postrelease adjustment period). In two sites heavily used by Scoters, diurnal observations revealed no predation attempts and low rates of predator disturbances that altered Scoter behavior (≤0.22/h). These and other results suggest that predation by Bald Eagles occurs mainly at sites and times where densities of Scoters are low, while most predation by mustelids probably occurs when Scoters are energetically compromised.

Reproductive success of bald eagles (Haliaeetus leucocephalus) and its association with habitat or landscape features and weather in southeast Alaska

1997 ◽  
Vol 75 (10) ◽  
pp. 1595-1604 ◽  
Author(s):  
Scott M. Gende ◽  
Mary F. Wilson ◽  
Mike Jacobsen
Keyword(s):  
Early Spring ◽  
Average Density ◽  
Nesting Success ◽  
Egg Laying ◽  
Haliaeetus Leucocephalus ◽  
Bald Eagles ◽  
Active Nest ◽  
Southeast Alaska ◽  
Landscape Features

Long-term data have been collected on nesting bald eagles (Haliaeetus leucocephalus) in three areas of southeast Alaska. The average density of active nests was among the highest recorded, but nest productivity (average number of young fledged per active nest) and success (percentage of active nests that fledged at least one young) were similar to values in other areas. Using logistic regression, nest productivity was associated with several habitat or landscape features (productivity was highest in proximity to spawning herring and at a particular location), each of which could be related to the availability of prey (fish) in the early spring (April, May) during egg laying and incubation. Consistency of nesting success was associated with the presence of tidal flats at one study site. Nest use, but not nesting success, was related to nesting success the previous year. Multiple regression showed that fewer nests per kilometre were successful in years with a high frequency of spring rains.

Host and geographic distribution of Skrjabinoclava spp. (Nematoda: Acuarioidea) in Nearctic shorebirds (Aves: Charadriiformes), and evidence for transmission in marine habitats in staging and wintering areas

1990 ◽  
Vol 68 (12) ◽  
pp. 2539-2552 ◽  
Author(s):  
P. L. Wong ◽  
R. C. Anderson
Keyword(s):  
Gulf Of Mexico ◽  
Pacific Coast ◽  
The United States ◽  
Larval Stages ◽  
Marine Habitats ◽  
The Pacific ◽  
Southern Alberta ◽  
Wintering Areas ◽  
Charadrius Wilsonia ◽  
Charadrius Semipalmatus

Twelve species of shorebirds belonging to the families Charadriidae (N = 3) and Scolopacidae (N = 9) were infected with 11 species of Skrjabinoclava and there was little overlap of parasites between these two families of birds. Most Skrjabinoclava spp. are transmitted apparently in marine staging and (or) wintering areas of their hosts, as indicated by the presence of larval stages of six species. There was no evidence that transmission occurs on the breeding grounds in freshwater habitats. Skrjabinoclava tupacincai, found predominantly in sanderlings (Calidris alba (Pallas)), is transmitted on the Pacific (Washington, California, Chile) and Atlantic coasts (New Jersey) in winter and the Gulf of Mexico (Florida and Texas) in winter and spring. Skrjabinoclava myersi was found, with a single exception, only in sanderlings, and transmission is apparently restricted to coastal Washington and California in winter. Skrjabinoclava bakeri, found predominantly in western sandpipers (Calidris mauri Cabanis), is transmitted on the Pacific coast (California) and in the Gulf of Mexico in winter. Skrjabinoclava morrisoni and Skrjabinoclava pusillae were found mainly in semipalmated sandpipers (Calidrispusilla (L.)). Both parasites are transmitted in the Gulf of Mexico in spring, but S. morrisoni is also transmitted in the Bay of Fundy in fall. Skrjabinoclava inornatae, found mainly in willets (Catoptrophorus semipalmatus (Gmelin)), is transmitted in Louisiana, Texas, and Peru in winter. Skrjabinoclava kritscheri was found only in marbled godwits (Limosafedoa (L.)), and it is suggested that infected birds collected in southern Alberta in spring acquired their infections while wintering along the Pacific coast of the United States. Skrjabinoclava hartwichi, found in black turnstones (Arenaria melanocephala (Vigors)) wintering in California and ruddy turnstones (Arenaria interpres (L.)) wintering in Peru, is transmitted along the Pacific coast of North America. Skrjabinoclava semipalmatae was found in semipalmated plovers (Charadrius semipalmatus Bonaparte) wintering in California. Skrjabinoclava wilsoniae was found in Wilson's plover (Charadrius wilsonia Ord) wintering in Texas and in a black-bellied plover (Pluvialis squatarola (L.)) migrating through southern Alberta in spring. Skrjabinoclava bartlettae was found in black-bellied plovers collected in southern Alberta in spring and Louisiana in winter.

Phylogeography of black bears (Ursus americanus) of the Pacific Northwest

2000 ◽  
Vol 78 (7) ◽  
pp. 1218-1223 ◽  
Author(s):  
Karen D Stone ◽  
Joseph A Cook
Keyword(s):  
Pacific Northwest ◽  
Pacific Coast ◽  
Ursus Americanus ◽  
Black Bear ◽  
Data Set ◽  
Southeast Alaska ◽  
Additional Information ◽  
The North ◽  
The Pacific ◽  
And Control

Phylogeographic study across codistributed taxa provides temporal and spatial perspectives on the assemblage of communities. A repeated pattern of intraspecific diversification within several taxa of the Pacific Northwest has been documented, and we contribute additional information to this growing data set. We analyzed variation in two mitochondrial genes (cytochrome b and control region) for the black bear (Ursus americanus) and expand previous analyses of phylogeographic variation. Two lineages (coastal and continental) exist; the coastal lineage extends along the Pacific coast from the Takhin River north of Glacier Bay National Park, southeast Alaska, to northern California, whereas the continental lineage is more widespread, occurring from central Alaska to the east coast. Both lineages occur along the coast of southeast Alaska, where interlineage divergence ranged from 3.1 to 3.6% (uncorrected p distances). Multiple lineages of other species have also been identified from southeast Alaska, indicating a complex history for the assembly of biotic communities along the North Pacific coast. The overlapping of the distributions of the black bear lineages with those of other birds and mammals suggests comparable routes of colonization.

The Thorny Oyster and the Origins of Empire: Implications of Recently Uncovered Spondylus Imagery from Chan Chan, Peru

1996 ◽  
Vol 7 (4) ◽  
pp. 313-340 ◽  
Author(s):  
Joanne Pillsbury
Keyword(s):  
Pacific Coast ◽  
Early Stage ◽  
Critical Element ◽  
Long Distance ◽  
Documentary Sources ◽  
The Pacific ◽  
Political Economies ◽  
Trade And Exchange ◽  
Exchange Network

The acquisition and use of exotic, valuable, and ritually important elite goods is a prominent feature of many imperial political economies. After an extensive review of the archaeological and documentary sources on one specific valuable in the empire of Chimor, this paper analyzes the visual representation of such goods, an aspect seldom addressed by archaeologists. An architectural relief recently excavated at Chan Chan, the capital of Chimor, sheds new light on the use of exotic materials and long-distance trade and exchange along the Pacific coast of South America in the late Prehispanic period. This relief, named "Los Buceadores" (The Divers) for the principal imagery depicting Spondylus divers, is important for elucidating the role of this valuable in the early development of the Chimú empire. It is argued that the Chimú rulers sponsored a long-distance exchange network during an early stage of the expansion of the Chimú polity and that the fruits of this network, particularly Spondylus, formed a critical element in the formation and maintenance of the ritual and economic basis of power for the expanding state.

Phenology and duration of remigial moult in Surf Scoters (Melanitta perspicillata) and White-winged Scoters (Melanitta fusca) on the Pacific coast of North America

2012 ◽  
Vol 90 (8) ◽  
pp. 932-944 ◽  
Author(s):  
R.D. Dickson ◽  
D. Esler ◽  
J.W. Hupp ◽  
E.M. Anderson ◽  
J.R. Evenson ◽  
...  
Keyword(s):  
North America ◽  
Pacific Coast ◽  
Selective Pressure ◽  
Wing Loading ◽  
Melanitta Perspicillata ◽  
The Pacific ◽  
Wide Range ◽  
Melanitta Fusca ◽  
Remigial Moult ◽  
Age And Sex

By quantifying phenology and duration of remigial moult in Surf Scoters ( Melanitta perspicillata (L., 1758)) and White-winged Scoters ( Melanitta fusca (L., 1758)), we tested whether timing of moult is dictated by temporal optima or constraints. Scoters (n = 3481) were captured during moult in Alaska, British Columbia, and Washington, and remigial emergence dates were determined. We provide evidence for a pre-emergence interval of 7.3 days that occurs after old primaries are shed and before new ones become visible. All age and sex classes of both scoter species exhibited a wide range of emergence dates (Surf Scoters: 26 June to 22 September; White-winged Scoters: 6 July to 21 September) suggestive of a lack of strong temporal optima for remigial moult. For both species, timing of moult was influenced by site, year, age, and sex. Relative to other waterfowl species, scoters have typical remigial growth rates (Surf Scoters: 3.9 mm·day–1; White-winged Scoters: 4.3 mm·day–1) but a long flightless period (34–49 days), in part because their relatively high wing-loading requires a greater proportion of feather regrowth to regain flight. Our data suggest that moulting scoters are not under strong selective pressure to complete moult quickly.

The Integration of Regional and Interregional Capital Markets: Evidence from the Pacific Coast, 1883–1913

1989 ◽  
Vol 49 (2) ◽  
pp. 297-310 ◽  
Author(s):  
Kerry A. Odell
Keyword(s):  
San Francisco ◽  
Financial Market ◽  
Market Integration ◽  
Pacific Coast ◽  
Capital Market Integration ◽  
Nineteenth Century America ◽  
The Pacific ◽  
National Capital ◽  
Commercial Market

The literature on national capital market integration in nineteenth-century America has overlooked the role of markets at a regional level. Such markets were important in reducing the possible burden of isolation by efficiently recycling local savings, and in promoting eventual integration into a national financial market. This article presents evidence that a commercial market centered on San Francisco extended into the Pacific Coast states and formed the basis for a regional financial market. The degree of market integration is measured through tests of interest rate covariability and convergence.

scholarly journals Bacterial Diversity in Feces of Wild Bald Eagles, Turkey Vultures and Common Ravens from the Pacific Northwest Coast, U.S.A

2019 ◽  
Author(s):  
Rocio Crespo ◽  
Scot E Dowd ◽  
Daniel E. Varland ◽  
Scott Ford ◽  
Thomas E. Hamer
Keyword(s):  
Bacterial Diversity ◽  
Pacific Northwest ◽  
Pathogenic Bacteria ◽  
Haliaeetus Leucocephalus ◽  
Bald Eagles ◽  
Cathartes Aura ◽  
Pacific Northwest Coast ◽  
16S Gene ◽  
The Pacific ◽  
Turkey Vultures

AbstractBirds harbor diverse microorganisms in their guts, which collectively fulfill important roles in providing their hosts with nutrition and protection from pathogens. Although numerous studies have investigated the presence of certain pathogenic bacteria in the feces of wild birds, only a few have attempted to investigate the microbiota of the gut. This study analyzed the avian bacteria present in the cloaca of avian scavengers captured on coastal beaches of Washington and Oregon between 2013 and 2015: 10 turkey vultures (Cathartes aura), 9 bald eagles (Haliaeetus leucocephalus), and 2 common ravens (Corvus corax). We used illumina sequencing based on the V4 region of the 16s gene was to characterize the bacterial diversity. Our investigation revealed phylum-level differences in the microbiome of turkey vultures, compared with bald eagles and common ravens. Substantial microbiome differences were found between bald eagles and ravens below the phylum level. Although little is known about the possible relations among these microorganisms, our analyses provides the first integrated look at the composition of the avian microbiota and serves as a foundation for future studies in this area.

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