Laughing Gulls (Larus atricilla) were studied along the south Texas coast during 1978-1981 to determine productivity and to evaluate the effects of environmental pollutants on reproduction. The average clutch-size was 2.6, ranging from 2.3-2.8. Sixty-six percent of the eggs hatched and 82% of the pairs hatched at least one egg. Productivity (fledglings/total nests) averaged 1.0 fledgling per nest. DDE and other organochlorine residues were low in eggs (usually <3 ppm wet weight) and were not suspected of causing reproductive problems. However, organophosphate pesticides sprayed on crops near the study areas reduced productivity by as much as 33% during 3 of 4 years, implying that certain of these chemicals may pose serious threats to the population.
Additional publication details
Nesting biology of laughing gulls in relation to agricultural chemicals in south Texas, 1978-81