Effects of egg order on organic and inorganic element concentrations and egg characteristics in tree swallows, tachycineta bicolor

Environmental Toxicology and Chemistry
By: , and 



The laying order of tree swallow eggs was identified from the Housatonic River, Berkshire County, Massachusetts, USA, and eggs were chemically analyzed individually to document possible effects of laying order on organic contaminant and inorganic element concentrations. Effects of laying order on other parameters such as egg weight, size, and lipid and moisture content also were assessed. Some effects of egg order on total polychlorinated biphenyls (PCBs) were detected, but the effect was not uniform across individual females or between years. In 2004, clutches with higher total PCBs tended to have concentrations decline across egg order, whereas clutches with lower concentrations of PCBs tended to increase across egg order. In contrast, in 2005, there was a tendency for concentrations to increase across egg order. Polychlorinated biphenyl concentrations were highly variable within and among clutches in both years. The directionality of egg order associations (i.e., slopes) for trace elements was element dependent, was positive for Mn and Zn, was negative for B, and had no slope for Cr. Whole egg weight increased across egg order. Percentage lipid was variable within a clutch, with no pattern common across all females. Percentage lipid was also correlated with organic contaminant concentration. In highly contaminated environments, higher lipid content could have the unanticipated corollary of having higher concentrations of lipophilic contaminants such as PCBs. To reduce the effect of high variation within a clutch when assessing contamination exposure, it is recommended that two eggs per clutch be collected and pooled for chemical analysis. We further recommend that, as long as the two eggs are randomly collected, the additional effort needed to identify and collect specific eggs is not warranted.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Effects of egg order on organic and inorganic element concentrations and egg characteristics in tree swallows, tachycineta bicolor
Series title Environmental Toxicology and Chemistry
DOI 10.1002/etc.88
Volume 29
Issue 4
Year Published 2010
Language English
Publisher SETAC
Contributing office(s) Contaminant Biology Program
Description 13 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Environmental Toxicology and Chemistry
First page 909
Last page 921
Country United States
State Massachusetts
County Berkshire
Other Geospatial Housatonic River
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