Causes of change

There is little good evidence available regarding the drivers of the breeding population change in this species in the UK.

Further information on causes of change

Historical decreases in Raven numbers across the UK occurred but the population has increased again during from the mid-twentieth century and the species has reoccupied much of its former range. This has bought it into conflict with people due to concerns about damage to livestock. Adult survival rates and breeding productivity have increased over time, and the consequent population recovery was most likely aided by reduced persecution; ringing recovery information suggests that the frequency of illegal killing may have declined in the twenty-first century, although this finding should be treated with caution as another possible interpretation is that ringed birds which have been shot and poisoned birds are now less likely to be reported. Recent increases in licensed control have occurred in Scotland, and a report investigating population dynamics has therefore been carried out in order to assess the effects of control on Scottish raven populations (Wilson et al. 2019).

Information about conservation actions

The Raven has been increasing and expanding its range in the UK over the last 30 years and therefore is not currently a species of conservation concern. However, there are also concerns that illegal control may be occurring (see Causes of Change section, above) which could have local population level impacts in some areas.

This species causes conflict with farmers due to concerns about damage to livestock and legal control now occurs in Scotland. There are also concerns about the possible impact of Raven populations on other native species such as upland waders. For example, a study looking at the UK uplands found no significant spatial or temporal relationships which could justify lethal control of Ravens between any of the five species of waders studied, but did find near significant relationships with curlew and lapwing trends, which the authors suggested merited further investigation (Amar et al. 2010b).

To ensure that the conservation status of this species remains unchanged and that the recent gains are not reversed, any policy decisions about the legal control of Ravens, whether for economic reasons or in order to benefit other native species, should be based on scientific evidence. A review in Scotland used population modelling to assess the effects of licenced control of Raven and define levels of control that are likely to be 'sustainable' (Wilson et al. 2019). They concluded that the maximum level of 'sustainable' control (i.e. control that will not result in long-term decline) is around 200 non-breeding Ravens per 100 x 100 km square in Scotland. However, they caution that this figure is subject to uncertainty around some of the information input into the model and to variation in aspects such as adult survival rates and breeding densities; hence the level of sustainable control may be lower in some areas and further understanding of Raven movements and breeding ecology is needed. Further research is also still be required in order to make evidence-based decisions about control in order to benefit other native species (e.g. research into the possible effects of Ravens on Curlews and Lapwings).