ABSTRACT Several potential proximate causes may be implicated in a recent (post-1984) decline moose (Alces alces andersoni) numbers at their southern range periphery northwest Minnesota, USA. These include deleterious effects of infectious pathogens, some which are associated with white-tailed deer (Odocoileus virginianus), negative climate change, increased food competition or moose, legal illegal hunting, and predation by gray wolves (Canis lupus) black bears (Ursus americanus)....

-Nine species of herons, egrets, and ibises were followed by airplane from a nesting colony near Beaufort, North Carolina to their feeding sites. Except for Cattle Egrets, which flew exclusively fields dumps, the birds mainly saltmarsh habitat. The selection habitats Great Egrets Louisiana Herons was directly related tidal depth. Egret only that effectively used eelgrass beds, its use this habitat restricted between 1.5 h before after low tide. We suspect shorter-legged herons did not...

Hatching success of tree swallows (Tachycineta bicolor) was assessed for three years in relation to chemical contamination along the Housatonic River, Berkshire County (MA, USA), 1998, 1999, and 2000. Nest boxes were erected at five sites River its tributaries one reference location. Concentrations total polychlorinated biphenyls (PCBs) some highest ever reported bird eggs. Mean concentrations ranged between 32 101 microg/g wet weight. A significant negative relationship observed PCBs...

American kestrels were fed a diet containing 0.5, 120, 212, and 448 ppm (dry wt) biologically incorporated lead (Pb) for 60 days. The consisted of homogenized 4-wk-old cockerels raised on feed mixed with without lead. No died weights did not differ among treatment groups. control group (0.5 Pb) had the lowest mean concentration high dietary highest following tissues: Kidney, liver, femur, brain, blood. Concentrations significantly correlated tissues. There no differences groups packed cell...

Abstract In 1994 and 1995, nesting success of double-crested cormorants (Phalacrocorax auritus) was measured at Cat Island, in southern Green Bay, Lake Michigan, Wisconsin, USA. Sample eggs pipping unhatched were collected analyzed for organochlorines (including total polychlorinated biphenyls [PCBs] DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity embryos, eggshell thickness. Of 1,570 laid, 32% did not hatch 0.4% had deformed embryos. 632 chicks monitored from hatching...

Abstract Concentration, accumulation, and effects of polychlorinated biphenyls (PCBs) o nreproduction in tree swallows (Tachycineta bicolor) were studied at four sites the Fox River drainage Green Bay, Lake Michigan, Wisconsin, USA, 1994 1995. Total PCBs eggs newly hatched young (mean = 3.01 μg/g wet weight, years combined) 12-d-old nestlings 2.34 weight) two contaminated (Kidney Island Arrowhead) higher than concentrations reference (Lake Poygan High Cliff State Park, combined, pippers mean...

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) three polluted sites (Cat Island, Green Bay, Lake Michigan, WI; Bair San Francisco CA; West Marin CA). In laboratory study, artificially incubated treated with 3‐methylcholanthrene (200 μg administered into air cell 2 d before...

Colonial waterbirds are an important natural resource highly valued by many people in Canada and the United States. The habit of nesting often large groups makes these birds especially susceptible to problems, such as human disturbance, predation, severe weather events, competition for habitat. They, like all birds, also face threats from habitat degradation, loss contamination their environments, changes food webs. Management strategies deal with problems include preservation restoration,...

Abstract In 1979, we gathered clutch-size and reproductive-success data on Black-crowned Night-Herons (Nycticorax nycticorax) nesting in three New England two North Carolina colonies. 1975, similar from one of the Latitudinal differences clutch initiation were not evident. Mean size was larger than smaller late nests colony studied both years another 1979; seasonal trends for other colonies found. nest success greater colony. Within-season occurred but inconsistent among four instances where...

-Breeding density, clutch size, hatching and fledging success, survival of adult Lapland Longspurs (Calcarius lapponicus) were monitored over a 7-year period near the Naval Arctic Research Laboratory, Barrow, Alaska. Nesting begins as soon tundra starts to clear snow appears be timed so that young year reach independence before end insect emergence. Arthropod prey become abruptly scarce after emergence thus probability success for late broods is low. Time nesting also discussed in relation...

Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in tree swallows (Tachycineta bicolor) nesting along the Woonasquatucket River northwest Providence (RI, USA) 2000 and 2001 were some highest ever reported avian tissues. Mean concentrations eggs ranged from 300 to >1,000 pg/g wet weight at two most contaminated ponds, Allendale Lyman. egg Greystone, upstream reference pond, 12 29 pg/g. Positive accumulation rates diet samples 12-day-old nestlings indicated that contamination was...

Abstract Belted kingfisher ( Ceryle alcyon ), spotted sandpiper Actitus macularia and tree swallow Tachycineta bicolor ) eggs were collected in 2004 from the upper Hudson River, New York, USA. This area is one of most polychlorinated biphenyl (PCB)‐contaminated locations North America. Multivariate analyses indicated among species differences concentration composition PCB congeners, dibenzo‐ p ‐dioxin (PCDD), dibenzofuran (PCDF, PCDD‐F when combined with PCDDs) chlorinated pesticides. Total...

Abstract In 1993, great blue heron (Ardea herodias; GBH) eggs were collected from 10 colonies on the upper Mississippi River (UMR). They then artificially incubated until pipping and analyzed for mercury, selenium, organochlorines. Livers of embryos hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity four measures oxidative stress. Brains measured asymmetry blood was coefficient variation DNA (DNA CV). Organochlorine concentrations generally low (geometric mean DDE = 1.3 μg/g wet...

Abstract Pipping black-crowned night-heron (Nycticorax nycticorax) embryos were collected from a relatively uncontaminated site (next to Chincoteague National Wildlife Refuge, VA) and three polluted sites (Cat Island, Green Bay, Lake Michigan, WI; Bair San Francisco CA; West Marin CA). Hepatic cytochrome P450-associated monooxygenases P450 proteins, induced up 85-fold relative the reference site, associated with concentrations of total polychlonrinated biphenyls (PCBs) 11 PCB congeners that...

Tree swallow (Tachycineta bicolor) and house wren (Troglodytes aedon) eggs chicks were collected near a refinery site on the North Platte River, Casper. Wyoming, USA at reference 10 km upstream. Total polycyclic aromatic hydrocarbon (PAH) concentrations in higher than site. Polycyclic sediment chick dietary samples consistent with these findings. The general lack of methylated PAHs sediment, diet, bird carcasses suggested that derived from combustion not petroleum. predominance odd-numbered...