Once again, the use of poisoned bait to control predators is a frequent practice in several European countries such as Portugal, Spain, Croatia and Greece, among others. The principle causes of the resurgence of this illegal practice are the control of predators associated with small game hunting (foxes, genets, martens, wild cats, etc.), extensive livestock rearing (wolves and feral dogs), and the accessibility of highly toxic products for agricultural use. In the last few years, several raptor species have been seriously affected. In Greece, entire colonies of Griffon Vultures have disappeared, similarly in Croatia, where the Griffon Vulture is very affected by poisoned carcases. In France, Bearded and Griffon Vultures have died from poison in the Pyrenees, in northern Portugal, wolves are eradicated with poison and in Spain, where there has been a serious effort to deal with the problem, 73 Spanish Imperial Eagles (Aquila adalberti), 17 Bearded Vultures (Gypaetus barbatus), 454 Black Vultures (Aegypius monachus), 788 Griffon Vultures (Gyps fulvus) and 411 Red Kites (Milvus milvus) are among the species found poisoned. To combat this, the BVCF, local and international NGOs and governments are developing or putting into operation various initiatives across the continent.

Prior to 1970, Saker Falcon (Falco cherrug) records for Mongolia were accrued and published merely as incidental observations made during research expeditions. In 1994, there began in earnest studies of Sakers all across Mongolia. These focused on breeding distribution, on the variety of colour morphs, on productivity, and on habitat use. From this we learned that the species exists in sizable populations from extreme western to extreme eastern zones, that it is common in dry steppe and montane steppe habitat, and is sparsely distributed in forest, tall grass, and desert habitats. Cliff nesting is most common, but many pairs use trees and artificial structures. In 1993, there began illegal removal of Sakers for Arab falconry, and smuggling is now rampant. Arab moneys flow into Mongolia to pay for smuggled falcons and for unscientific research which promotes the falcon harvest. To offset this, in 1997 we began constructing artificial eyries in zones where nest support structures were limited. Some 150 were created through 1999. We provide an overview of the research by various teams from the mid-1970s onward. By 1998, two competing foreign teams were involved. The team financed by Arab sheiks and promoting the falcon harvest had by 2000 arranged for exclusion of the team not involved in falcon traffic. The history of Saker conservation in Mongolia illustrates the key features of the use of science (both by Mongols and foreign agents) as a Trojan Horse in promoting wildlife exploitation.

After the pesticide crash Peregrines almost completely recovered in western and central Europe, there nesting on cliffs and buildings. Contrarily the area of tree-nesting Peregrine, where they became extinct, has remained vacant up to now. This area of wooded diluvial lowlands formerly contained some thousands of pairs, a large proportion of all Peregriees in Europe. As recently became known through complete individual marking in eastern Germany, tree-nesting is not adopted by the offspring of neighbouring building- and cliff-nesters. Instead, tree-nesting was initiated there again by imprinting reared young on this type of nesting during releases. Six new pairs have at present been re-established and are the only known examples between Berlin and Moscow. Their offspring nest not only on trees but in part also on buildings and cliffs., whereas there is a zero backflow to tree-nesting. Thus tree-nesters form an isolated subpopulation. This new knowledge leads to the following conclusions:

• In Peregrines tree-nesting is based on imprinting and spreads by tradition.
• Offspring from cliffs or buildings will not adopt tree-nesting.
• Save surviving tree-nesters to enable spontaneous resettlement of their huge vacant area.
• By releases of young imprinted on tree-nesting a new tradition can be initiated in completely unoccupied areas within the tree-nesting range.

In the western parts of the Netherlands Goshawks colonized a study area where a population of raptors had been surveyed since 1961. In the area all nests of raptors and owls were located and breeding results were registered. The study area is 34 sq km and holds 6 sq km of forests only. In 1993 the first nest of Goshawks was found and the population rapidly increased to 11 pairs in 1999. This is an extremely high density for an area so poor in forests. Food analyses of the Goshawks showed that Sparrowhawks were taken regularly. The population of 6 to 7 pairs of Sparrowhawks was almost exterminated after a few years of Goshawk regime.

This paper describes the effect of the presence of Goshawks on the breeding performance of Sparrowhawks before and after the presence of the Goshawks.

The choice of nesting place, clutch size and breeding results of the pairs that survived were very different from those pairs living without the presence of Goshawks in the study area.

Research ond habitat relationships of raptors and owls has sharply increased during the last decades. I assessed study systems, methods and the main findings in 896 studies that explored hypotheses about raptor-habitat relationships. Ten species accounted for half of the publications and 90% of these were carried out in North America or Europe. Hence, a critical conservation issue is whether, and how, the knowledge can be extrapolated to other situations. Yet only 19% of studies generalized their results beyond target species.

Methodologically, there have been some major developments over time. I summarized findings about varying quality of individual sites and landscapes, preemptive use of habitats, interaction between site and individual quality, and the development of site-quality recognition by birds of prey. Finally, I listed four major gaps of knowledge, the filling of which could significantly enhance both theory and management (sources and patterns of interspecific, geographic and temporal variation in raptor-habitat relationships; adaptivity and trade-offs of habitat selection; concepts of habitat patch and diversity for raptors).

Our current understanding of population regulation in raptors comes largely from long-term studies of natural raptor populations (both stable and recovering). With the recent advances in avian conservation management, much of which has been pioneered for the conservation of raptors, translocations and in particular re-introductions are becoming more commonplace. These re-introductions, whereby populations are successfully restored to areas from which they were originally extirpated, offer unique opportunities to study in detail population regulatory processes over the course of a population’s development. One such successful re-introduction was the Mauritius Kestrel into the Bambous Mountain range on the east coast of Mauritius. Since its inception in 1987 the developing population, which now appears to be showing signs of regulation, has been closely monitored and detailed demographic and ecological data collected. These data permit us to examine the influence of density-dependent and -independent processes on key demographic parameters. We summarise details of the data collected to date and the different aspects of population regulation that could be explored, illustrating the potential contribution re-introduced populations offer to furthering our understanding of population regulation in raptors.

The Tawny Owl (Strix aluco) is a newcomer to southern Finland. How the population of this southern generalist is regulated in the climate and cyclic food-supply of the northernmost area of its distribution? This analysis is based on (1) my 37-year study on Tawny and Ural Owls (Strix uralensis) and supplemented by two other long-term studies, (2) 20 years of nation-wide monitoring of birds of prey and (3) data from the Finnish Ringing Scheme (1913-2002: 37043 ringings and 9848 recoveries). The three-year vole cycle has a significant effect on productivity, survival, and natal dispersal of the Tawny Owl. Two or three times more young are produced in peak vole years than in low ones. Because of the crash of voles, juvenile survival after the peak is significantly lower (27%) than after the increase and low phases (37%). Further, only 11% of fledglings hatched in the peak vs. 50% hatched in the other phases can start breeding in their 2nd calendar year. For these reasons, the recruitment rate of young produced in peak years is much lower than of young produced in other phases of the cycle. Survival is also significantly correlated with snow depth and temperature.

Few studies have focused on the process of settlement on territory by migratory raptors. We investigated the potential causes and consequences of the date of settlement on breeding territory by migratory Black Kites Milvus migrans.

Date of settlement by males and females was recorded for seven consecutive years (1993-1998) for a population of about 33-44 pairs located in the Italian pre-Alps. At the population level, the mean yearly settlement date did not change through the years, despite a progressive advancement in laying date, probably related to climate warming. This may cause a long-term decline in the duration of the pre-laying period, with potential population level consequences. Within years, higher quality territories were occupied earlier than lower quality ones by both males and females. Finally, pairs with earlier arrival dates had higher subsequent breeding success. Overall, the observed settlement pattern conformed to the ideal despotic model of bird distribution.

The Saker, previously quite common and a typical raptor of the steppes and deserts nowadays has declined due to land degradation, habitat conversion, direct persecution, and in the past 20 years commercial exploitation. Its range, formerly spread from Western Europe to Korea, has shrunk, ceased to be continuous and split into at least two parts. Our surveys in the range countries have returned up-to-date estimates of density and total numbers of Sakers in the range countries as well as productivity data. Conventional and satellite radiotracking was used in studies of territory use and migration paths of the falcons. We found evidence of a ‘leap-frog’ type of migration in Sakers. A microchipping project (PIT) initiated in 1994 aimed to estimate the proportion of Sakers trapped for use in falconry. We have estimated the total number of falcons (mostly females) used for falconry in the Middle East to be as many as 6500 individuals. Compare with the 3900 to 5100 pairs of Sakers breeding successfully in all parts of the range. General knowledge on the numbers, survival and breeding rates of wild Sakers and the captive falcon data allow us to create a numerical model of Saker population trends and to simulate various scenarios of falcon removal rates. The current removal rates are not sustainable regardless of the high breeding rate of the species.

© 2003 CTM