Showing papers by "The Lodge published in 1994"

Seasonal variation in heavy metal levels in tissues of common guillemots, Uria aalge from Northwest Scotland

Abstract: Mercury, cadmium, zinc, and copper concentrations were analyzed in three samples of common guillemot (in April, June, and November). Levels measured were uniformly low, and not enough to have any toxic effects. Adult guillemots had significantly more cadmium in their livers and kidneys than juveniles, with juvenile levels ranging from 25% to 89% of adult levels. Mercury concentrations in liver and kidney were also higher in adults. Juvenile levels represented from 80% to 94% of adults, but there were no age differences in feather and muscle mercury. Mercury levels declined throughout the year in internal tissues from April through June to November. There was a strong seasonal fluctuation in cadmium levels in liver and kidney, rising significantly between April and June and declining again from June to November. These changes were apparent in both adult and juvenile birds. The influences of seasonal processes (namely breeding and moult) and seasonal dietary differences as causative factors in the changes in metal burdens are discussed. These findings have implications for the use of seabirds as monitors of heavy metals in the marine environment.

Habitat selection of Cirl Buntings Emberiza cirlus wintering in Britain

Abstract: The habitat selected by foraging Cirl Buntings was investigated at 2 sites in South Devon, England in each of 3 winters. Cirl Buntings showed a marked preference for foraging on stubble or fallow fields at both sites in all 3 winters of the study. A reduction in the area of stubble fields left over winter may have contributed to the decline of the British Cirl Bunting population.

Causes of nest failure among buntings in the UK

Abstract: Causes of nest failure among the four lowland buntings in the UK, Yellowhammer, Cirl Bunting, Reed Bunting and Corn Bunting, were investigated using records from 1924–¸92 held by the BTO's Nest Record Scheme. Three main types of failure were identified: nest-predation, destruction by agricultural operations (e.g. crop harvesting, cattle trampling, hedge cutting) and natural causes (e.g. rain, adult predated). Nest predation accounted for a third of nests of Yellowhammer, Cirl Bunting and Reed Bunting but was less important for Corn Bunting. Nest predation was more prevalent during the nestling stage than egg stage, and failure due to agricultural operations occurred more during the egg stage than nestling stage for Yellowhammer and Reed Bunting. Many farmland species have shown population declines since 1970, coinciding with changes in predator populations, farming practices and possibly weather patterns, and the relative importance of each cause in pre- and post-1970 samples was therefore compared. Corn ...