Organochlorines and mercury in the eggs of British Peregrines Falco peregrinus

Abstract

The levels of various contaminants were measured in 550 addled and deserted Peregrine Falco peregrinus eggs obtained in Britain during 1963‐86. In this period the population was recovering from a low level imposed by organochlorine pesticides. Over the whole period, HEOD levels declined in eggs from both inland and coastal regions, while DDE levels declined in eggs from inland regions. At the same time, shell‐indices improved. PCB levels increased in eggs from inland regions. At any one time, levels of DDE and HEOD in eggs decreased and shell‐indices increased from south to north within Britain. These gradients fitted with the extent of agricultural land (= pesticide use) and with the extent of Peregrine population decline (both greatest in the south). No south‐north trend was apparent in levels of PCBs derived from industrial sources. In some regions eggs from coastal sites were more contaminated than eggs from inland sites, especially with PCBs and mercury. Significant relationships were found between brood sizes and DDE levels, between brood sizes and shell‐indices, and between shell‐indices and DDE levels. This implied that DDE influenced shell thickness and breeding success. Some evidence was obtained that mercury reduced brood sizes, but no evidence that HEOD and PCB (at the levels found) did so. Overall, DDE and mercury levels together accounted for 17% of the variance in brood sizes during 1963‐86. On a regional basis, DDE had no obvious effect on mean productivity when the geometric mean DDE level in collected eggs was less than 3 p.p.m., and when mean shell‐index was no more than 8% less than normal. At higher DDE levels, and lower shell‐indices, productivity declined markedly. Recovery of regional populations was associated with geometric mean HEOD levels in eggs no greater than 0–7 p.p.m., DDE levels no greater than 15 p.p.m., shell indices no more than about 15–20% below normal, and a mean breeding success exceeding 0–6 young per territorial pair.

Persistent Organochlorine Pesticide Residues in Tissues and Eggs of White-Backed Vulture, Gyps bengalensis from Different Locations in India

“…Further the recorded levels are lower than the threshold level of 0.5 lg/g (Castillo et al 1994), and also less than the levels which had impaired reproductive success in pelican (King et al 1985). Newton et al (1979) reported 15% eggshell thinning in European kestrel which had 4-5 lg/g of DDE. Clark et al (1998) reported 50% productivity loss in bald eagle which had 6.3 lg/g of DDE in the eggs.…”

Territory occupancy and breeding success of Peregrine FalconsFalco peregrinusat various stages of population recovery

“…When our study started, the breeding range of Peregrines in Scotland was contracted, the population was at its lowest level and only 16% of the breeding pairs fledged young (Ratcliffe ); by the mid 1980s, reductions in organochlorine pesticide use resulted in a lessening of the effects on Peregrines (Newton et al . ). These observations are consistent with our findings that R 1 and R 2 were very low during the 1960s to 1970s, and increased steadily over time as the effects of organochlorines disappeared from the population.…”

Dispersal: a matter of scale

“…However, following restrictions on organochlorine pesticides, the British Peregrine population began to recover in the 1970s, increased through the 1990s, thereafter became relatively stable (Ratcliffe , Nisbet , Newton et al. , Banks et al. , Smith et al.…”