What did George Schaller note when studying the lions of the Serengeti? How does Piotr Naskrecki use relational databases and electronic field notes? In what way is Bernd Heinrich's approach "truly ...Thoreauvian," in E. O. Wilson's view? Pioneering a new niche in the study of plants and animals in their native habitat,Field Notes on Science and Natureallows readers to peer over the shoulders and into the notebooks of a dozen eminent field workers, to study firsthand their methods, materials, and fleeting impressions. Recording field observations is an indispensable scientific skill, but researchers are not generally willing to share their personal records. Here, for the first time, are reproductions of actual pages from notebooks. And in essays abounding with fascinating anecdotes, the authors reflect on the contexts in which the notes were taken. Covering disciplines as diverse as ecology, paleontology, anthropology, botany, and animal behavior,Field Notesoffers specific examples that professional naturalists can emulate to fine-tune their own field methods, along with practical advice that amateur naturalists and students can use to document their adventures.
Eggs from 21 resident great blue heron (Ardea herodias) rookeries were monitored from 1983 to 1998 along the coast of British Columbia, Canada, for contamination with polychlorinated ...dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs). Dominant congeners (1,2,3,7,8-PnCDD, 1,2,3,6,7,8-HxCDD, 2,3,7,8-TCDD, 2,3,7,8-TCDF, 1,2,3,7,8,9-HxCDD and 2,3,4,7,8-PnCDF) fell markedly in the early 1990s after pulp mills changed from molecular chlorine bleaching to alternative bleaching technologies, and the use of chlorophenolic wood preservatives and anti-sapstains was severely restricted. Strong positive linear regressions between prey fish and heron egg contaminant levels suggested that local dietary uptake was an important route of exposure for herons. Toxic equivalent concentrations (TEQs) sufficient to produce embryotoxicity in great blue heron chicks were measured in eggs from 1985 to 1991 at some colonies. Despite reduction in PCDD/Fs, estimated TEQs remained elevated throughout the 1980s at some urban colonies due to contributions from PCBs.
Because of their dependence on habitats and resources in different geographic regions at different phases of their annual cycle, migratory species are especially vulnerable to the impacts of climate ...change. In Bird Migration and Global Change, eminent ecologist George W. Cox brings his extensive experience to bear in evaluating the capacity of migratory birds to adapt to the challenges of a changing climate. The author reviews, synthesizes, and interprets recent and emerging science on the subject, beginning with a discussion of climate change and its effect on habitat, and followed by eleven chapters that examine responses of bird types across all regions of the globe. The final chapters address the evolutionary capacity of birds, and consider how best to shape conservation strategies to protect migratory species in coming decades.
We investigated unhatched eggs (n = 57) of Goshawks (Accipiter gentilis) from the period 1988–2002 and compared them with eggs (n = 134) from 1971–1978. Mean concentrations of PCBs, ∑DDT and HCB in ...the earlier period were (mg kg−1 lipid weight) 50.1, 126.6, and 117.7, while the values from the later period were statistically significantly lower: 27.7, 4.1, 0.1, respectively. Nevertheless, the concentration of PCB is relatively constant during the last 8–10 years. The variability of residues was lower within clutches than among clutches. No age-dependent accumulation in eggs could be demonstrated. A statistically significant lower shell index was measurable for the period 1971–1978, while this index during 2001–2002 was relatively high as it was during the late 18th century. We are suggesting a threshold value for effect concentrations on shell index. Residues of the DDT-group had an influence on the number of fledged young per nest site.
Mesozoic Birds Chiappe, Luis M; Witmer, Lawrence M
2001
eBook
Our knowledge of the origin and early evolution of birds has exploded in the past ten to fifteen years. In the 1990s alone, scientists became aware of approximately three times more species of early ...birds than were previously known, marking the first 85 million years of avian development as a period of remarkable species diversity.
