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Black-Crowned Night Heron

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Roger L. Hothem – 1st expert on this subject based on the ideXlab platform

  • Reproductive Success of Black-Crowned NightHerons (Nycticorax nycticorax) at Alcatraz Island, San Francisco Bay, California, 1990-2002
    , 2020
    Co-Authors: Roger L. Hothem

    Abstract:

    ? Nesting chronology, habitat use, subcolony use, and hatchability were documented for Blackcrowned NightHerons (Nycticorax nycticorax) nesting at Alcatraz Island during 1990-2002. Reproductive success was estimated using the Mayfield method and compared among years. Totals of monitored nests per year ranged from 68 in 2001 to 341 in 1996, with a trend toward declining numbers since 1996. A trend of increasing numbers of nests of Western Gulls, the primary competitor with the Black-Crowned NightHerons, was identified during the same period. Calculated nest success has generally declined since 1994, with success less than the 13-year average of 63.9% each of the last six years. Although fledging success declined to its nadir in 1997, the 13-year average was 87.6%, and the rate has generally increased during the past 5 years. The net result, however, has been that the overall reproductive success of Black-Crowned NightHerons at Alcatraz Island has been below the 13-year average of 56.3% since 1996. During the study, the average number of chicks fledged per nest ranged from 0.46 to 1.27 chicks per monitored nest, far below the required two chicks per nest required for a sustained population. Embryos in 5 of the 187 failed Blackcrowned NightHeron eggs that were examined contained deformed embryos. In 1990 and 1991 eggs were analyzed for a wide range of contaminants, but none appeared to be sufficiently elevated to have caused the observed deformities. Based on these relatively low levels of contaminants, a high hatchability rate (94.5%), and relatively low levels of embryotoxicity, contaminants did not appear to significantly affect Black-Crowned NightHeron reproduction at Alcatraz Island. However, predation by Common Ravens (Corvus corax) and Western Gulls (Larus occidentalis), interspecific competition with the Western Gulls, habitat deterioration, and possible human disturbance are likely factors contributing to the decline in Black-Crowned NightHeron reproduction on Alcatraz Island in recent years. Studies conducted in the early 1980s suggested that environmental contaminants were adversely affecting reproduction by Black-Crowned NightHerons (Nycticorax nycticorax) nesting in South San Francisco Bay (Ohlendorf et al. 1988; Hoffman et al. 1986). A project designed to evaluate the effects of contaminants on the reproductive success of Black-Crowned NightHerons and Snowy Egrets (Egretta thula) nesting in San Francisco Bay was initiated in 1989 and included Alcatraz Island beginning in 1990 (Hothem et al. 1995). Black-Crowned NightHerons had nested on Alcatraz Island since at least the early 1980s, with estimates of total nests ranging from 24 in 1981 (Boarman 1989) to about 60 in 1989 (M. Alvarez and T. Thomas, Golden Gate National Recreation Area, unpubl. data). Although gross numbers of nests had been estimated sporadically, neither the reproductive success of the colony nor the potential adverse impacts of environmental contaminants on reproduction had been estimated. In addition, to facilitate the conservation of nesting birds on Alcatraz, the National Park Service (NPS) needed data on nesting, hatching, and fledging success of Black-Crowned NightHerons to facilitate their planning for increased visitor access to the island. In 2002, we monitored Black-Crowned NightHeron reproduction at Alcatraz for the thirteenth consecutive year. METHODS Study Area The study site was Alcatraz Island (37 49’ N, 122 25’ W), a National Historic Landmark within the Golden Gate National Recreation Area. This 9.1-ha island, in the central portion of San Francisco Bay, about

  • Reproductive Success of the Black-Crowned Night Heron at Alcatraz Island, San Francisco Bay, California, 1990-2002
    Waterbirds, 2004
    Co-Authors: Roger L. Hothem, Daphne Hatch

    Abstract:

    Abstract Nesting chronology, habitat use, subcolony use, and hatchability were documented for the Black-Crowned Night Heron (Nycticorax nycticorax) nesting at Alcatraz Island, San Francisco Bay, California during 1990-2002. Reproductive success was estimated using the Mayfield method and compared among years. Totals of monitored nests per year ranged from 68 in 2001 to 341 in 1996, with a trend of declining numbers since 1996. An increase in numbers of the Western Gull (Larus occidentalis), the Black-Crowned Night Heron’s primary competitor, occurred during the same period. Overall reproductive success of the Black-Crowned Night Heron at Alcatraz Island was below the 13-year average of 56.4% since 1996. During the study, the average number of chicks fledged per nest each year ranged from 0.46 to 1.27, which is less than the two chicks per nest suggested as a requirement for a sustained population. Embryos in five of 187 failed Black-Crowned Night Heron eggs were deformed. In 1990 and 1991, eggs were analy…

  • Biomonitoring environmental contamination with pipping black‐crowned Night Heron embryos: Induction of cytochrome P450
    Environmental Toxicology and Chemistry, 1993
    Co-Authors: Barnett A. Rattner, Roger L. Hothem, Thomas W. Custer, Mark J. Melancon, Kirke A. King, Leonard J. Lecaptain, James W. Spann, Bruce R. Woodin, John J. Stegeman

    Abstract:

    Cytochrome P450-associated monooxygenase activities and cytochrome P450 proteins were measured in pipping Black-Crowned Night Heron (Nycticorax nycticorax) embryos collected from a reference site (next to the Chincoteague National Wildlife Refuge, VA) and three polluted sites (Cat Island, Green Bay, Lake Michigan, WI; Bair Island, San Francisco Bay, CA; West Marin Island, San Francisco Bay, CA). In a laboratory study, artificially incubated Night Heron embryos from the reference site were treated with 3-methylcholanthrene (200 μg administered into the air cell 2 d before pipping) or phenobarbital (2 mg daily for 2 d before pipping). Compared to controls (untreated + vehicle-treated embryos), 3-methylcholanthrene induced a greater than fivefold increase in activities of several monooxygenases (arylhydrocarbon hydroxylase, AHH; benzyloxyresorufin-O-dealkylase, BROD; ethoxyresorufin-O-dealkylase, EROD; pentoxyresorufin-O-dealkylase, PROD) and a greater than 100-fold increase in the concentration of immunodetected cytochrome P450 1A (CYP1A). Phenobarbital treatment resulted in only a slight increase in BROD activity but induced proteins recognized by antibodies to cytochrome P450 2B (CYP2B) by 2,000-fold. In a field study, activities of AHH, BROD, EROD, and ethoxycoumarin-O-dealkylase (ECOD) were up to 85-fold higher in pipping Black-Crowned Night Herons collected from Cat Island compared to other sites. Hepatic CYP1A and CYP2B cross-reactive proteins were detected in significantly more individuals from Cat Island than from the reference site. Greatest burdens of total PCBs and p,p′-DDE were detected in embryos from Cat Island. Cytochrome P450-associated monooxygenase activities and cytochrome P450 proteins (AHH, BROD, EROD, ECOD, CYP1A, CYP2B) were significantly associated with total PCB burdens (r = 0.50-0.72). These data indicate that cytochrome P450 may be a useful biomarker of exposure to some PCB mixtures in Black-Crowned Night Heron embryos.

Barnett A. Rattner – 2nd expert on this subject based on the ideXlab platform

  • Absorption and biotransformation of polybrominated diphenyl ethers DE-71 and DE-79 in chicken (Gallus gallus), mallard (Anas platyrhynchos), American kestrel (Falco sparverius) and Black-Crowned NightHeron (Nycticorax nycticorax) eggs.
    Chemosphere, 2010
    Co-Authors: Moira Mckernan, Barnett A. Rattner, Jeff S. Hatfield, Robert C. Hale, Mary Ann Ottinger

    Abstract:

    Abstract We recently reported that air cell administration of penta-brominated diphenyl ether (penta-BDE; DE-71) evokes biochemical and immunologic effects in chicken ( Gallus gallus ) embryos at very low doses, and impairs pipping (i.e., stage immediately prior to hatching) and hatching success at 1.8 μg g −1 egg (actual dose absorbed) in American kestrels ( Falco sparverius ). In the present study, absorption of polybrominated diphenyl ether (PBDE) congeners was measured following air cell administration of a penta-BDE mixture (11.1 μg DE-71 g −1 egg) or an octa-brominated diphenyl ether mixture (octa-BDE; DE-79; 15.4 μg DE-79 g −1 egg). Uptake of PBDE congeners was measured at 24 h post-injection, midway through incubation, and at pipping in chicken, mallard ( Anas platyrhynchos ), and American kestrel egg contents, and at the end of incubation in Black-Crowned NightHeron ( Nycticorax nycticorax ) egg contents. Absorption of penta-BDE and octa-BDE from the air cell into egg contents occurred throughout incubation; at pipping, up to 29.6% of penta-BDE was absorbed, but only 1.40–6.48% of octa-BDE was absorbed. Higher brominated congeners appeared to be absorbed more slowly than lower brominated congeners, and uptake rate was inversely proportional to the log K ow of predominant BDE congeners. Six congeners or co-eluting pairs of congeners were detected in penta-BDE-treated eggs that were not found in the dosing solution suggesting debromination in the developing embryo, extraembryonic membranes, and possibly even in the air cell membrane. This study demonstrates the importance of determining the fraction of xenobiotic absorbed into the egg following air cell administration for estimation of the lowest-observed-effect level.

  • Element Patterns in Feathers of Nestling Black-Crowned NightHerons, Nycticorax nycticorax L., from Four Colonies in Delaware, Maryland, and Minnesota
    Bulletin of Environmental Contamination and Toxicology, 2008
    Co-Authors: Thomas W. Custer, Nancy H. Golden, Barnett A. Rattner

    Abstract:

    The pattern of elements in nestling Black-Crowned NightHeron feathers from a rural Minnesota colony differed from colonies in industrialized regions of Maryland and Delaware. Except for chromium, however, the differences did not reflect the elements associated with waters and sediments of the Maryland and Delaware colonies. Therefore, elements in water and sediment do not necessarily bioaccumulate in NightHeron feathers in relation to potential exposure. Although trace element patterns in feathers indicated differences among geographical locations, they did not separate all locations well and their usefulness as an indicator of natal colony location may be limited.

  • Organochlorine contaminant exposure and reproductive success of Black-Crowned Night Herons (Nycticorax nycticorax) nesting in Baltimore Harbor, Maryland
    Archives of Environmental Contamination and Toxicology, 2001
    Co-Authors: Barnett A. Rattner, Peter C. Mcgowan, J. S. Hatfield, Chia-swee Hong

    Abstract:

    The declining size of the Baltimore Harbor Black-Crowned NightHeron (Nycticorax nycticorax) colony has been hypothesized to be linked to polychlorinated biphenyl (PCB) exposure. In 1998, a “sample egg” was collected from 65 Black-Crowned NightHeron nests (each containing ≥ three eggs) for contaminant analysis, and the remaining eggs in these 65 nests, plus four two-egg nests, were monitored for hatching and fledging success. Eggs were also collected from 12 nests at Holland Island, a reference site in southern Chesapeake Bay. Samples were analyzed for 26 organochlorine pesticides and metabolities and 145 PCB congeners. Pesticide and metabolite concentrations, including p,p’-DDE, were well below thresholds associated with adverse reproductive effects at both sites. Average concentration of total PCBs, 12 Ah receptor–active PCB congeners, and toxic equivalents in eggs from Baltimore Harbor were greater (up to 35-fold) than that observed in Holland Island samples. Overall nest success at the Baltimore Harbor Heronry was estimated by the Mayfield method to be 0.74, and the mean number of young fledged/hen was 2.05, which is within published productivity estimates for maintaining a stable Black-Crowned NightHeron population. Using logistic regression, no significant relationships were found between organochlorine contaminant concentrations in sample eggs and hatching, fledging, or overall reproductive success. Processes other than poor reproduction (e.g., low postfledging survival, emigration, habitat degradation) may be responsible for the declining size of the Baltimore Harbor colony.

Thomas W. Custer – 3rd expert on this subject based on the ideXlab platform

  • Contaminant exposure and biomarker response in embryos of Black-Crowned NightHerons (Nycticorax nycticorax) nesting near Lake Calumet, Illinois
    Journal of Great Lakes Research, 2020
    Co-Authors: Jeffrey M. Levengood, Thomas W. Custer, Mark J. Melancon, Luann Wiedenmann, David J. Schaeffer, Cole W. Matson, David J. Hoffman, John W. Scott, Jonathan L. Talbott, Gary Bordson

    Abstract:

    ABSTRACT We examined a suite of environmental contaminants and exposure endpoints in Black-Crowned NightHeron (Nycticorax nycticorax, BCNH) embryos collected in 2002 from colonies in Illinois, Minnesota, and Virginia. Embryos from the Lake Calumet, IL, colony had greater exposure to polychlorinated biphenyls (PCBs), 4,4′-dichlorodiphenyldichloroethylene (DDE), dieldrin, transnonachlor, oxy-chlordane, cobalt, copper, and selenium than did those from northwest MN and coastal VA. Embryos from IL and VA contained greater concentrations of mercury and zinc than those from MN, whereas the latter had greater accumulation of lead. Greater exposure of IL embryos to PCBs was reflected in greater ethoxyresorufin-O-deethylase and benzyloxyresorufin-O-dealkylase induction. However, measures of oxidative stress and genotoxicity were similar to those in embryos from the other colonies examined, and no overt toxic effects of contaminant exposure such as embryo mortality or malformations were observed. Although efforts t…

  • Contaminant exposure of birds nesting in Green Bay, Wisconsin, USA.
    Environmental Toxicology and Chemistry, 2014
    Co-Authors: Thomas W. Custer, Christine M. Custer, Paul Michael Howell Dummer, J. Christian Franson, Michael Jones

    Abstract:

    In earlier studies, elevated concentrations of polychlorinated biphenyl (PCB) and p,p’-dichlorodiphenyldichloroethylene (DDE) were reported in double-crested cormorant (Phalacrocorax auritus) eggs and tree swallow (Tachycineta bicolor) eggs and nestlings collected from lower Green Bay (WI, USA) in 1994 and 1995 and Black-Crowned NightHeron (Nycticorax nycticorax) eggs collected in 1991. Comparable samples collected in 2010 and 2011 indicated that concentrations of PCBs were 35%, 62%, 70%, and 88% lower than in the early 1990s in tree swallow eggs, tree swallow nestlings, double-crested cormorant eggs, and Black-Crowned NightHeron eggs, respectively; concentrations of DDE were 47%, 43%, 51%, and 80% lower, respectively. These declines are consistent with regional contaminant trends in other species. Concentrations of PCBs were higher in herring gull (Larus argentatus) than in Black-Crowned NightHeron eggs collected from Green Bay in 2010; PCB concentrations in double-crested cormorant and tree swallow eggs were intermediate. The estimated toxicity of the PCB mixture in eggs of the insectivorous tree swallow was the equal to or greater than toxicity in the 3 piscivorous bird species. A multivariate analysis indicated that the composition percentage of lower-numbered PCB congeners was greater in eggs of the insectivorous tree swallow than in eggs of the 3 piscivorous species nesting in Green Bay. Dioxin and furan concentrations and the toxicity of these chemicals were also higher in tree swallows than these other waterbird species nesting in Green Bay. Environ Toxicol Chem 2014;33:1832–1839. Published 2014 Wiley Periodicals, Inc. Published 2014 Wiley Periodicals, Inc. This article is a US Government work and, as such, is in the public domain in the USA.

  • Element Patterns in Feathers of Nestling Black-Crowned NightHerons, Nycticorax nycticorax L., from Four Colonies in Delaware, Maryland, and Minnesota
    Bulletin of Environmental Contamination and Toxicology, 2008
    Co-Authors: Thomas W. Custer, Nancy H. Golden, Barnett A. Rattner

    Abstract:

    The pattern of elements in nestling Black-Crowned NightHeron feathers from a rural Minnesota colony differed from colonies in industrialized regions of Maryland and Delaware. Except for chromium, however, the differences did not reflect the elements associated with waters and sediments of the Maryland and Delaware colonies. Therefore, elements in water and sediment do not necessarily bioaccumulate in NightHeron feathers in relation to potential exposure. Although trace element patterns in feathers indicated differences among geographical locations, they did not separate all locations well and their usefulness as an indicator of natal colony location may be limited.