Landfills are used as the primary means for the disposal of municipal solid waste in Canada. In the present study, polybrominated diphenyl ethers (PBDEs) and other flame retardants (FRs) were determined in fresh European starling ( Sturnus vulgaris ) eggs collected in 2009, 2010, and 2011 from nest boxes established within, adjacent to, and 10 and 40 km distant to five major urban centers across Canada, i.e., Vancouver, British Columbia (BC); Calgary, Alberta (AB); Hamilton, Ontario (ON); Montréal, Québec (QC); and Halifax, Nova Scotia (NS). Nest boxes were located in several land use types: urban industrial areas (districts of industrial activity within city limits), landfill sites (adjacent to cities), and rural (agricultural) sites located 10 and 40 km distant from the major urban centers, as well as a national reference site. Of the 14 PBDE congeners and 16 non-PBDE FR substances determined in the starling eggs, BDE-17, -28, -47, -49, -66, -85, -99, -100, -138, -153, -154, -183, and -209, Dechlorane Plus isomers (anti and syn), and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (BEHTBP) were most frequently quantifiable. The data revealed orders of magnitude greater PBDE concentrations in eggs from starlings nesting in landfill sites (median: 28-280 ng/g wet weight) relative to those from urban industrial and rural environments. However, the percent fractional composition of the PBDE congener patterns did not vary significantly between the types of land uses or between years. Additionally, the median ∑PBDE concentration in eggs from landfill sites and the human population density of the metropolitan region that the landfill serves were highly correlated (r(2) = 0.998, p < 0.001). As the first transcontinental effort in assessing FR contamination in Canadian terrestrial ecosystems, the present study strongly suggest that landfills are an important FR source to starlings nesting nearby and that other terrestrial organisms could also be similarly exposed.

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Abstract-We conducted a field experiment to determine the direct and indirect effects of spraying two broad-spectrum insecticides with widely differing avian toxicities in grassland habitat on the survival and reproductive success of nesting songbirds. Three 56-ha plots were sprayed with Decis 5F, three plots were sprayed with Furadan 480F, and three plots were left unsprayed. Insecticides were applied at rates recommended for grasshopper control. Grasshopper (Orthoptera: Acrididae) density was measured throughout the spring and summer. Nests of chestnut-collared longspurs (Calcarius ornatus) were monitored to determine survival rates and nestling growth. Food habits of nestlings and parental foraging parameters were measured using esophageal ligatures and observations of parental foraging flights. Applications of both insecticides decreased grasshopper populations by more than 90%. Nevertheless, the number of grasshoppers in nestling diets was significantly decreased only in nests in Decis-sprayed plots. Total arthropod biomass delivered to the nestlings did not decrease in plots sprayed with either insecticide. Nestling weight and size were unaffected by insecticide spraying. Rate of prey delivery also did not change; however, by two weeks after spraying with Decis, parent longspurs were foraging almost twice as far from their nests as were birds in control plots (p Ͻ 0.05) to maintain prey delivery rates. Clutch size and egg and nestling success were similar among treated and control plots within specific two-week periods during the season. Age-corrected brain acetylcholinesterase activities of longspur nestlings in plots sprayed with Furadan were significantly depressed compared to controls; a single case of insecticide-induced mortality was detected in a nestling that was severely infested with blowfly larvae. Nevertheless, success of nests with Furadan-exposed nestlings (n ϭ 20) was greater than that in control plots during the two-week period following spray (n ϭ 19, p ϭ 0.03). The Baird's sparrow (Ammodramus bairdii), an uncommon prairie species of conservation concern, was monitored using an index of productivity. The number of 3.14-ha census circles having productive Baird's sparrow territories was significantly lower in Furadan-sprayed plots than in unsprayed and Decis-sprayed plots; a larger number of sparrow territories were abandoned in Furadan plots.

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