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 ===== Introduction ===== ===== Introduction =====
  
-Are corvids cold blooded killers or merely opportunistic scavengers? This is the question we are trying to answer in this blog post. Mainstream media and advertising businesses often have a tendency to present an idyllic and idealised version of farming practices, showcasing for example animals living in picturesque environments. This imagery is employed to evoke positive emotions and create a connection with consumers. It is nothing else than a marketing strategy aimed at promoting the products derived from the use of non-human animals, such as meat or wool, by associating them with positive and wholesome images. Humans have a natural inclination to connect with and appreciate the beauty of animals. The sight of a playful and adorable lamb triggers positive emotions, such as joy and warmth, which does evoke empathy and a sense of compassion.+{{ :2016-11-04_5648.jpeg?200|}}Are corvids cold blooded killers or merely opportunistic scavengers? This is the question we are trying to answer in this blog post. Mainstream media and advertising businesses often have a tendency to present an idyllic and idealised version of farming practices, showcasing for example animals living in picturesque environments. This imagery is employed to evoke positive emotions and create a connection with consumers. It is nothing else than a marketing strategy aimed at promoting the products derived from the use of non-human animals, such as meat or wool, by associating them with positive and wholesome images. Humans have a natural inclination to connect with and appreciate the beauty of animals. The sight of a playful and adorable lamb triggers positive emotions, such as joy and warmth, which does evoke empathy and a sense of compassion.
  
 Bearing this in mind, then it is not surprising that the sight of corvids scavenging on such an innocent being will without a doubt be repulsive for most people, who will immediately sympathise with the victim, and not with the scavenger. Unfortunately, media representations of such wildlife interactions with domesticated non-human animals are commonly very much one-sided, despite the well known fact that it is always essential to consider all nuances and complexities of such interactions. Bearing this in mind, then it is not surprising that the sight of corvids scavenging on such an innocent being will without a doubt be repulsive for most people, who will immediately sympathise with the victim, and not with the scavenger. Unfortunately, media representations of such wildlife interactions with domesticated non-human animals are commonly very much one-sided, despite the well known fact that it is always essential to consider all nuances and complexities of such interactions.
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 The same study also found that most crow attacks on live lambs took place on animals, which had reached an extremely weak condition due to starvation or some other cause. The researcher concluded that one cannot include the losses in the study group of lambs in any estimate of the damage caused by crows, because their chances of survival anyway must be considered as negligible. The same study also found that most crow attacks on live lambs took place on animals, which had reached an extremely weak condition due to starvation or some other cause. The researcher concluded that one cannot include the losses in the study group of lambs in any estimate of the damage caused by crows, because their chances of survival anyway must be considered as negligible.
  
-The study also concluded that there are probably two main conditions in which lambs are vulnerable to crow attacks. Firstly, all lambs, whether viable or not, may be attacked shortly after birth when both the ewe and the lamb are weak and may not be able to defend themselves. And secondly, any lambs, which become weak after birth due to disease, exposure or starvation, will again become vulnerable to crow attacks when they become weak again, shortly before they would have died anyway. In this context, other studies have found that the likelihood of predator attacks increases when twins or triplets are born, who are particularly prone to hypothermia and subsequently disease due to their low birth weight, and the prolonged birth period, which renders the ewe unable to defend their offspring. (11) +The study also concluded that there are probably two main conditions in which lambs are vulnerable to crow attacks. Firstly, all lambs, whether viable or not, may be attacked shortly after birth when both the ewe and the lamb are weak and may not be able to defend themselves. And secondly, any lambs, which become weak after birth due to disease, exposure or starvation, will again become vulnerable to crow attacks when they become weak again, shortly before they would have died anyway. In this context, other studies have found that the likelihood of predator attacks increases when twins or triplets are born, who are particularly prone to hypothermia and subsequently disease due to their low birth weight, and the prolonged birth period, which renders the ewe unable to defend their offspring. ((“The Effect of Hooded Crows on Hill Sheep Farming in Argyll, Scotland: Hooded Crow Damage to Hill Sheep.” Journal of Applied Ecology, vol. 14, no. 1, 1977, pp. 17–29. JSTOR, https://doi.org/10.2307/2401823. Accessed 7 Aug. 2023.)) 
  
 ===== A Case of Advanced Scapegoating ===== ===== A Case of Advanced Scapegoating =====
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 It is essential to recognise that the decline of songbird populations is typically the result of a combination of these factors, and the relative importance of each factor can vary depending on the specific songbird species and the region within the UK. It is essential to recognise that the decline of songbird populations is typically the result of a combination of these factors, and the relative importance of each factor can vary depending on the specific songbird species and the region within the UK.
  
-As mentioned above, a similar and not less controversial topic in this context is the role of domestic free roaming cats and their impact on natural ecosystems. However, the way this scientifically proven and rather serious problem is being discussed, acknowledged and dealt with is rather different, when compared to the discussed interactions between sheep and corvids. Here we can see the completely opposite approach, whereas the domestic predator is being granted the freedom to roam and to kill at will, and anyone questioning this approach is at risk to be verbally attacked by the responsible guardian of the animal concerned.   (12, 13, 14, 15, 16, 17, 18, 19, 20)     +As mentioned above, a similar and not less controversial topic in this context is the role of domestic free roaming cats and their impact on natural ecosystems. However, the way this scientifically proven and rather serious problem is being discussed, acknowledged and dealt with is rather different, when compared to the discussed interactions between sheep and corvids. Here we can see the completely opposite approach, whereas the domestic predator is being granted the freedom to roam and to kill at will, and anyone questioning this approach is at risk to be verbally attacked by the responsible guardian of the animal concerned. ((Coˆté, I. M., and Sutherland, W. J. (1997). The effectiveness of Removing predators to protect bird populations. Conserv. Biol. 11 (2), 395–405. doi:10.1046/j.1523- 1739.1997.95410.x)) ((Madden, C. F., Arroyo, B., and Amar, A. (2015). A review of the impacts of corvids on bird productivity and abundance. Ibis 157, 1–16. doi:10.1111/ibi.12223)) ((Lachmann, L., and Arnold, K. (2019). 15 Jahre Vogelzählung und Citizen Science im NABU – Ergebnisse der “Stunde der Gartenvögel” und der “Stunde der Wintervögel”. Berlin, Germany: NABU-Bundesverband.)) ((The widespread declines of songbirds in rural Britain do not correlate with the spread of their avian predators D. L. Thomson , R. E. Green , R. D. Gregory and S. R. Baillie Published: 07 November 1998 https://doi.org/10.1098/rspb.1998.0540)) ((Owens, I.P.F., Bennett, P.M. (2000) Ecological basis of extinction risk in birds: Habitat loss versus human persecution and introduced predators. PNAS. 97(22): 12144-12148)) ((Peach, W.J., Ratcliffe, N., Smith, K.W., Summers, R.W., Walton, P., Wilson, J.D. (2007) The predation of wild birds in the UK: a review of its conservation impact and management. RSPB Research Report no 23. RSPB, Sandy.)) ((Pirie, T.J., Thomas, R.L., Fellowes, M.D.E. (2022) Pet cats (Felis catus) from urban boundaries use different habitats, have larger home ranges and kill more prey than cats from the suburbs. Landscape and Urban Planning. 220: https://doi.org/10.1016/j.landurbplan.2021.104338)) ((Roos, S., Smart, J., Gibbons, D.W., Wilson, J.D. (2018) A review of predation as a limiting factor for bird populations in mesopredator-rich landscapes: a case study of the UK. Biological Reviews. 93(4): 1915-1937.)) ((Woods, M., McDonald, R.A., Harris, S. (2003) Predation of wildlife by domestic cats Felis catus in Great Britain. Mammal Review. 33: 174– 188.))  
-  +
 The topic of cats and wildlife is being discussed in separate blog posts, which can be found by following the links provided. The topic of cats and wildlife is being discussed in separate blog posts, which can be found by following the links provided.
 +
 +  * [[cats_cars_and_wildlife|Cats, Cars and Wildlife]]
 +  * [[top_reasons_to_keep_cats_indoors|Top Reasons to Keep Cats Indoors]]
  
 ===== Rural Rooks Destroying Crops ===== ===== Rural Rooks Destroying Crops =====
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 This being said, in a few cases, large rook populations may cause minor damage to crops, such as pecking at seedlings or foraging in newly sown fields. However, the degree of damage is usually exaggerated, which holds in particular true in spring. The required and preferred diet during breeding season is mainly based on animal protein, which includes bugs, grubs, insects and agricultural pests, which would in fact destroy the farmer’s crops, if they would not be harvested by rooks. Instead the farming community is using highly toxic pesticides with devastating consequences for our ecosystem. This being said, in a few cases, large rook populations may cause minor damage to crops, such as pecking at seedlings or foraging in newly sown fields. However, the degree of damage is usually exaggerated, which holds in particular true in spring. The required and preferred diet during breeding season is mainly based on animal protein, which includes bugs, grubs, insects and agricultural pests, which would in fact destroy the farmer’s crops, if they would not be harvested by rooks. Instead the farming community is using highly toxic pesticides with devastating consequences for our ecosystem.
  
-These facts should actually lead to the conclusion, that by understanding the ecological role of rooks and other bird species in agricultural landscapes, it would be crucial to promote sustainable farming practices whilst conserving biodiversity. However, this does only rarely seem the case.  (21, 22)+These facts should actually lead to the conclusion, that by understanding the ecological role of rooks and other bird species in agricultural landscapes, it would be crucial to promote sustainable farming practices whilst conserving biodiversity. However, this does only rarely seem the case. ((Gerber, R. (1956). Die Saatkrähe. Die neue Brehm-Bücherei vol 181. Wittenberg, Germany: Ziemsen.)) ((Veh, M. (1981). Überwinternde Saatkrähen in Nordbaden – Konflikt zwischen Naturschutz und Landwirtschaft und Vorschläge zu einer Lösung. Heidelberg, Germany: Dissertation University.)) 
  
 ===== Corvids Outsmarting Humans ===== ===== Corvids Outsmarting Humans =====
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 Corvids have been observed using tools to obtain food. They can fashion sticks, twigs, and even leaves into tools to extract insects from crevices or holes. Some species have also been seen dropping nuts or hard objects onto roads and waiting for cars to crack them open before retrieving the exposed edible parts. Corvids have excellent memory and can recall the locations of thousands of cached food items. They are also skilled at navigating complex environments and finding their way back to specific locations. Corvids have been observed using tools to obtain food. They can fashion sticks, twigs, and even leaves into tools to extract insects from crevices or holes. Some species have also been seen dropping nuts or hard objects onto roads and waiting for cars to crack them open before retrieving the exposed edible parts. Corvids have excellent memory and can recall the locations of thousands of cached food items. They are also skilled at navigating complex environments and finding their way back to specific locations.
  
-Corvids can learn from observing others, and not just their own kind, and may adopt new behaviours by watching their conspecifics. This ability to learn from each other contributes to the transmission of knowledge within their corvid community. Corvids exhibit sophisticated vocalisations and non-vocal signals to communicate with each other. They can warn each other about potential dangers, such as the presence of predators or humans with harmful intent. Some corvid species have demonstrated the ability to recognise individual human faces, even distinguishing between friendly and threatening individuals. This suggests a high level of perceptual intelligence. Corvids have shown the ability to use insight to solve novel problems without prior training or trial-and-error learning. This is considered an advanced cognitive skill. (23, 24, 25, 26, 27, 28, 29, 30, 31, 32)  +Corvids can learn from observing others, and not just their own kind, and may adopt new behaviours by watching their conspecifics. This ability to learn from each other contributes to the transmission of knowledge within their corvid community. Corvids exhibit sophisticated vocalisations and non-vocal signals to communicate with each other. They can warn each other about potential dangers, such as the presence of predators or humans with harmful intent. Some corvid species have demonstrated the ability to recognise individual human faces, even distinguishing between friendly and threatening individuals. This suggests a high level of perceptual intelligence. Corvids have shown the ability to use insight to solve novel problems without prior training or trial-and-error learning. This is considered an advanced cognitive skill. ((Weir, A. A., Chappell, J., and Kacelnik, A. (2002). Shaping of hooks in new caledonian crows. Science 297, 981. doi:10.1126/science.1073433)) ((Clayton, N. S., Dally, J. M., and Emery, N. J. (2007). Social cognition by food- caching corvids. The western scrub-jay as a natural psychologist. Philos. Trans. R. Soc. Lond. B Biol. Sci. 362, 507–522. doi:10.1098/rstb.2006.1992)) ((Clayton, N. S., and Dickinson, A. (1998). Episodic-like memory during cache recovery by scrub jays. Nature 395, 272–274. doi:10.1038/26216)) ((Raby, C. R., Alexis, D. M., Dickinson, A., and Clayton, N. S. (2007). Planning for the future by western scrub-jays. Nature 445, 919-921. doi:10.1038/nature05575)) ((Massen, J. J., Ritter, C., and Bugnyar, T. (2015). Tolerance and reward equity predict cooperation in ravens (Corvus corax). Sci. Rep. 5, 15021. doi:10.1038/srep15021)) ((Ditz, H. M., and Nieder, A. (2015). Neurons selective to the number of visual items in the corvid songbird endbrain. Proc. Natl. Acad. Sci. U.S.A. 112, 7827. doi:10.1073/pnas.1504245112)) ((Stahler, D., Heinrich, B., and Smith, D. (2002). Common ravens, Corvus corax, preferentially associate with grey wolves, Canis lupus, as a foraging strategy in winter. Anim. Behav. 64 (2), 283–290. doi:10.1006/anbe. 2002.3047)) ((Heinrich, B. (2014). Ravens in winter. New York, NY: Simon & Schuster.)) ((Krüger, T., and Nipkow, M. (2015). Die Saatkrähe Corvus Frugilegus als Brutvogel in Niedersachsen – Vorkommen, Schutz, Konflikte und Lösungsmöglichkeiten vol 35. in Jahrgang, nummer, 1. Hannover, Germany: Informationsdienst Naturschutz Niedersachsen.)) ((Despret, V. (2015). The enigma of the raven. Angelaki 20, 57–72. doi:10.1080/ 0969725x.2015.1039842))  
                  
 ===== Conclusion – Are Corvids Cold Blooded Killers or Merely Scavengers? ===== ===== Conclusion – Are Corvids Cold Blooded Killers or Merely Scavengers? =====
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 Media outlets often have business relationships with various industries, including the agricultural and food industries. These relationships shape the narrative and content that is promoted. As the livestock industry plays a significant role in the economy, media organisations are influenced by the interests of these industries and often choose not to cover processes that may raise ethical or environmental concerns. Also, media outlets often aim to appeal to their target audience and consider what content is likely to resonate with them. Media outlets often have business relationships with various industries, including the agricultural and food industries. These relationships shape the narrative and content that is promoted. As the livestock industry plays a significant role in the economy, media organisations are influenced by the interests of these industries and often choose not to cover processes that may raise ethical or environmental concerns. Also, media outlets often aim to appeal to their target audience and consider what content is likely to resonate with them.
  
-Scapegoating is often being used to distract from the reality of intensive agricultural farming practices, and their side effects, such as high lamb mortality. However, corvids are not the only ones, as other species such as badgers, foxes and birds or prey are equally blamed and misrepresented.  (33, 34, 35) +Scapegoating is often being used to distract from the reality of intensive agricultural farming practices, and their side effects, such as high lamb mortality. However, corvids are not the only ones, as other species such as badgers, foxes and birds or prey are equally blamed and misrepresented. ((Scottish Badgers, Badger and Lamb / Sheep Interaction Evidence Sheet, January 2023, https://www.scottishbadgers.org.uk/wp-content/uploads/2023/03/9-Fact-Sheet-SHEEP-AND-LAMBS.pdf)) ((Investigation into golden eagle predation of lambs on Benbecula in 2003, Steve Campbell and Gill Hartley, Scottish Agricultural Science Agency 2004.)) ((Scottish National Heritage, Commissioned Report No. 370, Is lamb survival in the Scottish Uplands related to the presence of breeding white-tailed eagles (Haliaeetus albicilla) as well as other livestock predators and environmental variables? A pilot study into sea eagle predation on lambs in the Gairloch area. https://raptorpersecutionscotland.files.wordpress.com/2010/05/b603609_wtelambstudygairloch_2010.pdf)) 
-Existing conflicts between farmers and conservationists regarding the management of bird populations create additional pressure on to the farming community. Farmers may argue that controlling corvid populations is necessary to protect crops and prevent economic losses, while conservationists may emphasise the importance of preserving biodiversity and protecting bird species. Painting a negative picture of these birds seems to be a way for farmers to garner support for their perspective and gain understanding for otherwise unjustifiable actions.  (36, 37, 38, 39, 40) +
- +
-Bibliography+
  
-    1. Tribe of Heart, https://www.tribeofheart.org/sr/home_english.htm  +Existing conflicts between farmers and conservationists regarding the management of bird populations create additional pressure on to the farming community. Farmers may argue that controlling corvid populations is necessary to protect crops and prevent economic losses, while conservationists may emphasise the importance of preserving biodiversity and protecting bird species. Painting a negative picture of these birds seems to be a way for farmers to garner support for their perspective and gain understanding for otherwise unjustifiable actions. ((Houston, David. “The Effect of Hooded Crows on Hill Sheep Farming in Argyll, Scotland: Hooded Crow Damage to Hill Sheep.” Journal of Applied Ecology, vol. 14, no. 1, 1977, pp. 17–29. JSTOR, https://doi.org/10.2307/2401823. Accessed 7 Aug. 2023.)) ((Owens, I.P.F., Bennett, P.M. (2000) Ecological basis of extinction risk in birds: Habitat loss versus human persecution and introduced predators. PNAS. 97(22): 12144-12148)) ((Pirie, T.J., Thomas, R.L., Fellowes, M.D.E. (2022) Pet cats (Felis catus) from urban boundaries use different habitats, have larger home ranges and kill more prey than cats from the suburbs. Landscape and Urban Planning. 220: https://doi.org/10.1016/j.landurbplan.2021.104338)) ((Roos, S., Smart, J., Gibbons, D.W., Wilson, J.D. (2018) A review of predation as a limiting factor for bird populations in mesopredator-rich landscapes: a case study of the UK. Biological Reviews. 93(4): 1915-1937.)) ((Woods, M., McDonald, R.A., Harris, S. (2003) Predation of wildlife by domestic cats Felis catus in Great Britain. Mammal Review. 33: 174– 188.))
-    2. Wolves, Crows, and Spiders: An eclectic Literature Review inspires a Model explaining Humans’ similar Reactions to ecologically different Wildlife. Front. Environ. Sci. 9:593501. doi: 10.3389/fenvs.2021.593501  +
-    3. Preventive Veterinary Medicine Volume 52, Issues 3–4, 22 January 2002, Pages 287-303  +
-    4. Neonatal lamb mortality: major risk factors and the potential ameliorative role of melatonin Tom Flinn, David O. Kleemann, Alyce M. Swinbourne, Jennifer M. Kelly, Alice C. Weaver, Simon K. Walker, Kathryn L. Gatford, Karen L. Kind and William H. E. J. van Wettere  +
-    5. Purser, A., & Young, G. (1964). Mortality among twin and single lambs. Animal Production, 6(3), 321-329. doi:10.1017/S000335610002211X +
-    6. Gunn, R., & Robinson, J. (1963). Lamb mortality in Scottish hill flocks. Animal Production, 5(1), 67-76. doi:10.1017/S000335610002153X  +
-    7. Houston, David. “The Effect of Hooded Crows on Hill Sheep Farming in Argyll, Scotland: Hooded Crow Damage to Hill Sheep.” Journal of Applied Ecology, vol. 14, no. 1, 1977, pp. 17–29. JSTOR, https://doi.org/10.2307/2401823. Accessed 7 Aug. 2023.  +
-    8. Brehme, A., Wallschläger, D., and Langemach, T. (2001). “Kolkraben und die Freilandhaltung von Weidetieren – untersuchungen aus dem Land Brandenburg,” in Die Rabenvögel im Visier (Bonn, Germany: Ökologischer Jagdverein), 19–32.  +
-    9. Hennig, V. (2018). Untersuchung zur Problematik der Kolkraben in der Schafhaltung – untersuchung im Auftrag des Ministeriums für Ländlichen Raum und Verbraucherschutz (2014–2016) bzw. des Ministeriums für Umwelt, Klima und Energiewirtschaft (2016–2017) in Baden- Württemberg; Untersuchung im Auftrag des Ministeriums für Ländlichen Raum und Verbraucherschutz in Baden-Württemberg (2014–2016).  +
-    10. Dwyer, C. M., Conington, J., Corbiere, F., Holmøy, I. H., Muri, K., Nowak, R., et al. (2016). Invited review: improving neonatal survival in small ruminants: science into practice. Animal 10 (3), 449–459. doi:10.1017/S1751731115001974  +
-    11. “The Effect of Hooded Crows on Hill Sheep Farming in Argyll, Scotland: Hooded Crow Damage to Hill Sheep.” Journal of Applied Ecology, vol. 14, no. 1, 1977, pp. 17–29. JSTOR, https://doi.org/10.2307/2401823. Accessed 7 Aug. 2023.  +
-    12. Coˆté, I. M., and Sutherland, W. J. (1997). The effectiveness of Removing predators to protect bird populations. Conserv. Biol. 11 (2), 395–405. doi:10.1046/j.1523- 1739.1997.95410.x  +
-    13. Madden, C. F., Arroyo, B., and Amar, A. (2015). A review of the impacts of corvids on bird productivity and abundance. Ibis 157, 1–16. doi:10.1111/ibi.12223  +
-    14. Lachmann, L., and Arnold, K. (2019). 15 Jahre Vogelzählung und Citizen Science im NABU – Ergebnisse der “Stunde der Gartenvögel” und der “Stunde der Wintervögel”. Berlin, Germany: NABU-Bundesverband.  +
-    15. The widespread declines of songbirds in rural Britain do not correlate with the spread of their avian predators D. L. Thomson , R. E. Green , R. D. Gregory and S. R. Baillie Published: 07 November 1998 https://doi.org/10.1098/rspb.1998.0540  +
-    16. Owens, I.P.F., Bennett, P.M. (2000) Ecological basis of extinction risk in birds: Habitat loss versus human persecution and introduced predators. PNAS. 97(22): 12144-12148  +
-    17. Peach, W.J., Ratcliffe, N., Smith, K.W., Summers, R.W., Walton, P., Wilson, J.D. (2007) The predation of wild birds in the UK: a review of its conservation impact and management. RSPB Research Report no 23. RSPB, Sandy.  +
-    18. Pirie, T.J., Thomas, R.L., Fellowes, M.D.E. (2022) Pet cats (Felis catus) from urban boundaries use different habitats, have larger home ranges and kill more prey than cats from the suburbs. Landscape and Urban Planning. 220: https://doi.org/10.1016/j.landurbplan.2021.104338  +
-    19. Roos, S., Smart, J., Gibbons, D.W., Wilson, J.D. (2018) A review of predation as a limiting factor for bird populations in mesopredator-rich landscapes: a case study of the UK. Biological Reviews. 93(4): 1915-1937.  +
-    20. Woods, M., McDonald, R.A., Harris, S. (2003) Predation of wildlife by domestic cats Felis catus in Great Britain. Mammal Review. 33: 174– 188.  +
-    21. Gerber, R. (1956). Die Saatkrähe. Die neue Brehm-Bücherei vol 181. Wittenberg, Germany: Ziemsen.  +
-    22. Veh, M. (1981). Überwinternde Saatkrähen in Nordbaden – Konflikt zwischen Naturschutz und Landwirtschaft und Vorschläge zu einer Lösung. Heidelberg, Germany: Dissertation University.  +
-    23. Weir, A. A., Chappell, J., and Kacelnik, A. (2002). Shaping of hooks in new caledonian crows. Science 297, 981. doi:10.1126/science.1073433 +
-    24. Clayton, N. S., Dally, J. M., and Emery, N. J. (2007). Social cognition by food- caching corvids. The western scrub-jay as a natural psychologist. Philos. Trans. R. Soc. Lond. B Biol. Sci. 362, 507–522. doi:10.1098/rstb.2006.1992  +
-    25. Clayton, N. S., and Dickinson, A. (1998). Episodic-like memory during cache recovery by scrub jays. Nature 395, 272–274. doi:10.1038/26216  +
-    26. Raby, C. R., Alexis, D. M., Dickinson, A., and Clayton, N. S. (2007). Planning for the future by western scrub-jays. Nature 445, 919-921. doi:10.1038/nature05575  +
-    27. Massen, J. J., Ritter, C., and Bugnyar, T. (2015). Tolerance and reward equity predict cooperation in ravens (Corvus corax). Sci. Rep. 5, 15021. doi:10.1038/srep15021  +
-    28. Ditz, H. M., and Nieder, A. (2015). Neurons selective to the number of visual items in the corvid songbird endbrain. Proc. Natl. Acad. Sci. U.S.A. 112, 7827. doi:10.1073/pnas.1504245112  +
-    29. Stahler, D., Heinrich, B., and Smith, D. (2002). Common ravens, Corvus corax, preferentially associate with grey wolves, Canis lupus, as a foraging strategy in winter. Anim. Behav. 64 (2), 283–290. doi:10.1006/anbe. 2002.3047  +
-    30. Heinrich, B. (2014). Ravens in winter. New York, NY: Simon & Schuster. +
-    31. Krüger, T., and Nipkow, M. (2015). Die Saatkrähe Corvus Frugilegus als Brutvogel in Niedersachsen – Vorkommen, Schutz, Konflikte und Lösungsmöglichkeiten vol 35. in Jahrgang, nummer, 1. Hannover, Germany: Informationsdienst Naturschutz Niedersachsen.  +
-    32. Despret, V. (2015). The enigma of the raven. Angelaki 20, 57–72. doi:10.1080/ 0969725x.2015.1039842  +
-    33. Scottish Badgers, Badger and Lamb / Sheep Interaction Evidence Sheet, January 2023, https://www.scottishbadgers.org.uk/wp-content/uploads/2023/03/9-Fact-Sheet-SHEEP-AND-LAMBS.pdf  +
-    34. Investigation into golden eagle predation of lambs on Benbecula in 2003, Steve Campbell and Gill Hartley, Scottish Agricultural Science Agency 2004.  +
-    35. Scottish National Heritage, Commissioned Report No. 370, Is lamb survival in the Scottish Uplands related to the presence of breeding white-tailed eagles (Haliaeetus albicilla) as well as other livestock predators and environmental variables? A pilot study into sea eagle predation on lambs in the Gairloch area. https://raptorpersecutionscotland.files.wordpress.com/2010/05/b603609_wtelambstudygairloch_2010.pdf  +
-    36. Houston, David. “The Effect of Hooded Crows on Hill Sheep Farming in Argyll, Scotland: Hooded Crow Damage to Hill Sheep.” Journal of Applied Ecology, vol. 14, no. 1, 1977, pp. 17–29. JSTOR, https://doi.org/10.2307/2401823. Accessed 7 Aug. 2023.  +
-    37. Owens, I.P.F., Bennett, P.M. (2000) Ecological basis of extinction risk in birds: Habitat loss versus human persecution and introduced predators. PNAS. 97(22): 12144-12148  +
-    38. Pirie, T.J., Thomas, R.L., Fellowes, M.D.E. (2022) Pet cats (Felis catus) from urban boundaries use different habitats, have larger home ranges and kill more prey than cats from the suburbs. Landscape and Urban Planning. 220: https://doi.org/10.1016/j.landurbplan.2021.104338  +
-    39. Roos, S., Smart, J., Gibbons, D.W., Wilson, J.D. (2018) A review of predation as a limiting factor for bird populations in mesopredator-rich landscapes: a case study of the UK. Biological Reviews. 93(4): 1915-1937.  +
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