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Year Published: 1996

Survival of northern pintail ducklings on the Yukon-Kuskokwim Delta, Alaska

We studied survival rates of Northern Pintail (Anas acuta; hereafter pintail) broods and ducklings along the lower Kashunuk River on the Yukon-Kuskokwim Delta, Alaska. Survival rates were determined for 770 ducklings in 111 broods. Brood sizes at hatch were smaller in 1993 versus 1991 and 1992. Duckling survival rates were lower than those...

Grand, James B.; Flint, Paul L.

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Year Published: 1996

Variation in egg size of the northern pintail

Egg size is an important determinant of reproductive investment by birds. For many species, total investment in a clutch is limited by the size of stored reserves (Ankney and MacInnes 1978, Esler and Grand 1994a). Egg size determines the unit by which these stored reserves are partitioned. Individual females in most species of waterfowl show a...

Flint, Paul L.; Grand, James B.

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Year Published: 1995

Estimating number of species and relative abundances in stream-fish communities: effects of sampling effort and discontinuous spatial distributions

We sampled fishes and measured microhabitat in series of contiguous habitat units (riffles, runs, pools) in three Virginia streams. We used Monte Carlo simulations to construct hypothetical series of habitat units, then examined how number of species, similarity in relative abundances, and number of microhabitats accumulated with increasing number...

Angermeier, Paul L.; Smogor, Roy A.

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Year Published: 1995

Monitoring exposure of nestling songbirds to agricultural application of an organophosphorus insecticide using cholinesterase activity

In June 1992 we collected 53 blood plasma samples from nestling red‐winged blackbirds (Agelaius phoeniceus), house sparrows (Passer domesticus), and brown‐headed cowbirds (Molothrus ater) at five study sites in northwestern Minnesota to evaluate the feasibility of using plasma and brain cholinesterase (ChE) activity and reactivation as a means of...

McInnes, Pamela F.; Andersen, David E.; Hoff, Dale J.; Hooper, Michael J.; Kinkel, L.K.

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Year Published: 1995

Nesting success of ducks on the central Yukon Flats, Alaska

Nesting success was studied at Canvasback Lake and Mallard Lake on the Yukon Flats in interior Alaska in 1989–1991. Simple estimates of nesting success were computed using two techniques that assume a constant daily survival rate (DSR). Maximum-likelihood estimates of nesting success for all ducks, assuming constant DSR, ranged among years and...

Grand, James B.

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Year Published: 1994

Decoy trapping and rocket-netting for northern pintails in spring

Decoy traps and rocket-nets were compared for capturing Northern Pintails (Anas acuta: hereafter pintails) during May 1991 on the Yukon Flats, Alaska. Males were captured at similar rates using both methods (1.38 vs. 1.07 males/trap d, respectively), but baited rocket-nets were more efficient than decoy traps for capturing females (0.52 vs. 0.12...

Grand, James B.; Fondell, Thomas F.

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Year Published: 1994

The role of nutrient reserves for clutch formation by Northern Pintails in Alaska

We analyzed carcass composition of female Northern Pintails (Anas acuta) in Alaska to assess the importance of nutrient reserves for formation of first clutches (n = 85) and renests (n = 39). Habitat (tundra vs. boreal forest), hen age (yearling vs. adult), and year (1990 vs. 1991) did not affect nutrient reserve use. During formation of first...

Esler, Daniel N.; Grand, James B.

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Year Published: 1993

Dynamics and distribution of black abalone populations at San Nicolas Island

Dense populations of black abalones (Haliotis cracherodii Leach) were monitored in permanent intertidal plots at nine sites on San Nicolas Island from 1981 through 1990. Densities were essentially constant at all four sites along the north shore of the island throughout the study period. Densities at five sites along the south shore were more...

Hochberg, F.G.; VanBlaricom, Glenn R.
Dynamics and distribution of black abalone populations at San Nicolas Island; 1993; Article; Conference publication; Third California Islands Symposium: Recent Advances in research on the California Islands; VanBlaricom, Glenn R.

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Year Published: 1993

Factors influencing depredation of artificial duck nests

Because artificial nests can facilitate controlled experiments of nest success, we used them to assess whether human visitation, nest density, vegetation structure, and proximity to habitat edge could affect depredation of duck nests on Yukon Flats National Wildlife Refuge, Alaska. More (P < 0.01) nests in a plot visited daily (100%) were...

Esler, Daniel N.; Grand, James B.

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Year Published: 1992

Breeding chronology of mottled ducks in a Texas coastal marsh

The relationship between breeding chronology of Mottled Ducks (Anas fulvigula fulvigula) and wetland conditions at San Bernard National Wildlife Refuge was examined over a 3-yr period. Median nest initiation dates varied by as much as 68 d among years. Initiation occurred earlier in 1985 and 1987 versus 1986 (P < 0.05). Nesting initiation was...

Grand, James B.

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Year Published: 1987

Aggressive encounters between tundra swans and greater white-fronted geese during brood rearing

Interspecific aggression in waterfowl (Anatidae) is relatively common (McKinney 1965; Kear 1972; Savard 1982, 1984), but interactions leading to mortality of one of the combatants are rarely-observed in the wild. A recent debate (Livezey and Humphrey 1985a, 1985b; Nuechterlein and Storer 1985a, 1985b; Murray 1985) has centered on the proximate and...

Ely, Craig R.; Budeau, David A.; Swain, Una G.