Bioaccumulation of Some Metals and Metalloids in Laughing Gulls (): Increases in Mercury and Decreases in Selenium from 2019 to 2022/2023.

The elements in blood normally reflect the levels in prey, indicating a recent exposure. Laughing gulls () eat mainly horseshoe crab eggs () in the spring in Delaware Bay, New Jersey. The levels of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) in the blood of laughing gulls foraging on crab eggs were examined in Delaware Bay to provide information on a species that is normally a generalist, and to determine if the levels of these elements were similar in 2019 and 2022/2023, were intercorrelated, and were related to those in crab eggs.

Some metals and metalloids in the blood of three species of shorebirds increase while foraging during two-week migratory stopover in Delaware Bay, New Jersey.

Most migratory shorebird species are declining, some are endangered, and some may be vulnerable to contaminants on long distance travel between wintering grounds and high latitude breeding grounds. We examined whether shorebirds accumulated trace elements at the Delaware Bay (New Jersey) stopover by testing the null hypothesis that there was no difference in the levels of arsenic, cadmium, chromium, lead, mercury, and selenium in blood of three species of shorebirds collected early in their stopover compared to levels in blood collected about two weeks later near the end of the stopover, before departing for breeding grounds. There were significantly higher levels of all metals and metalloids in the blood of ruddy turnstone (Arenaria interpres) later in May than earlier.

Sex hormones and the development of sexual size dimorphism: 5α-dihydrotestosterone inhibits growth in a female-larger lizard ().

Sexual differences in adult body size [sexual size dimorphism (SSD)] and color (sexual dichromatism) are widespread, and both male- and female-biased dimorphisms are observed even among closely related species. A growing body of evidence indicates testosterone can regulate growth, thus the development of SSD, and sexual dichromatism. However, the mechanism(s) underlying these effects are conjectural, including possible conversions of testosterone to estradiol (E) or 5α-dihydrotestosterone (DHT).