Mainly addressing the eradication of non-native mammals, particularly on islands, Warwick (an ecologist and public figure in the United Kingdom) delves into his qualms about killing animals in the ostensible service of conservation. He details cases well known to many invasion scientists (e.g., the gray squirrel in the UK, cane toad and rabbits in Australia, Burmese python in the US, hippopotamus in Colombia, Norway rat and house mouse on South Georgia, house mouse on Gough, ruddy duck in Spain and the UK, yellow crazy ant on Christmas Island) and others known at most locally or to cognoscenti, especially in the UK (e.g., Norway and ship rats on Lundy Island, Norway rats in the Scilly Islands, stoats in the Orkneys). Some that are not so prominent and will interest any reader are the array of invaders of Lord Howe Island, including the usual rodent suspects but also the masked owl and bleating tree frog, the smooth-billed ani in the Galapagos, and the raccoon in Haida Gwaii. Warwick also describes several methods of lethal control in more detail than many invasion scientists know... and in some cases would wish to know, but that is his point.

Each chapter is mainly about a specific eradication campaign (or lethal management) but usually includes discussion of related efforts and often broader issues. The first chapter is about hedgehogs in New Zealand, the Orkneys, and Uist (in the Outer Hebrides). This is unsurprising, as Warwick is best known as a hedgehog advocate and was heavily engaged in the prominent controversy over attempts to kill non-native hedgehogs on Uist or translocate them to mainland Great Britain in order to conserve wading birds. This case captures well the ethical dilemma over killing featured in all the chapters. The main foci are non-native mammals on Great Britain and its small islands and on New Zealand, especially the Predator Free 2050 campaign in the latter. In each chapter, the details of the campaign are depicted through conversations with individuals associated with the location, the target species, the campaign, or some combination of these. Some are people who travel with him to the site, usually minor UK celebrities who will be recognized by few outsiders. More interesting are non-celebrities—scientists, conservation NGO staff and advisors, a gamekeeper. Warwick manages to fit into these discursive chapters a remarkable number of important facets of invasions and how to deal with them, ranging from the philosophical (e.g., the ethical aspects of focusing on saving individuals vs. saving populations or entire species) to the technical (e.g., how gene drives work and their possible impact on management). Interspersed between chapters are “asides” of 2–4 pages. He has managed to cram a lot of information into some of these. Both chapters and asides have many striking statistics, and whenever I tracked one down, it was correct. How many know that 47 million pheasants and 13 million red-legged partridges are released annually in Great Britain, where neither is native? Throughout, the invaders and their impacts are accurately described and the writing is engaging, with many striking metaphors. Dominating each chapter is Warwick’s agonizing over his compassion for the dispatched animals combined with his recognition of the likely conservation loss if they are not killed. He is not optimistic that various proposed technofixes (e.g. contraception, gene drives) will resolve his dilemma in the short term.

Oddly, Warwick seems to believe that few managers doing the killing and scientists advocating it have not thought long and hard about the very ethical quandary that so perplexes him. He devotes a long chapter to compassionate conservation, with the major exposition depicted in an extended conversation with its founder, Marc Bekoff. He doesn’t question Bekoff’s ad hoc assertion that many who recommend lethal management “are looking at getting results from research that will lead to a paper being published or maybe getting tenure at a university” (p. 255). Remarkably, although compassionate conservation is a highly contested set of principles, with at least 20 papers in Conservation Biology alone between 2015 and 2020, mostly about non-native species on islands and about half highly critical of the approach, Warwick does not describe the objections or interview any of their authors.

After almost 300 pages of angst, Warwick finally advocates an “ethically consistent conservation” in his closing chapter, a “manifesto.” This consists of “nailing his colours” to a sort of middle ground: “those with a complete aversion to killing could maybe examine the implications of inaction as well as the horror of action” and “the traditional, dare I say it, New Zealand school of thought could reasonably accept a little more compassion into its toolbox” (p. 263). He does not detail how much more compassion would be reasonable and how it would be manifested. He is dismayed by his perception that targeted species are “othered” or demonized, although most of his interlocutors involved in lethal control clearly are not doing this. Like several post-modern critics of invasive species management (e.g., Haraway 2008; Subramaniam 2024), he opposes “binaries.”

In some ways, Warwick’s conclusion is a letdown, as it is more or less what the great majority of managers and scientists confronting damaging non-native populations have concluded. Warwick’s other main take-home message is the repeated admonition that, if we are to resolve conservation disputes, we should all talk a lot with one another, and especially with those with whom we don’t agree. Although he is surely aware of the notion of a “wicked problem” and how it has often been invoked in conservation and biological invasion papers, he never addresses its implication that sometimes ongoing interactions among stakeholders with different interests and/or values cannot lead to a resolution, even though they can lead to many publications.

Cull of the Wild will be an interesting, worthwhile read for any invasion scientist. This is not to say that it couldn’t have been better. It has a good index, but there are no citations to the myriad interesting cases and facts, and the only bibliography consists of nine general references. In almost every instance, it is easy with a little patience to find the appropriate citation through Google Scholar. Perhaps the publisher forbade end notes or a full bibliography in the interests of cost? This might also explain the complete absence of figures in a work that cries out for them, particularly because it targets a general readership. For instance, Warwick’s strained description of physical differences between “pure” Scottish wildcats and hybrids with housecats could have been obviated with a figure. For non-UK readers, a map of the UK with cited locations indicated would have been helpful. The frequent references to more or less obscure British popular or high culture are rarely crucial to the important points Warwick is making and doubtless enliven the work for British readers. His English and Scottish slang can usually be interpreted from context, though some is arcane (e.g., “moggy”). Considering the beautiful layout and cover, I was surprised by the shoddy proofreading.

A more substantive criticism is his somewhat muddled exposition of ethical theories in a work mainly focused on ethics. On pages 258–259 he finally presents the greatly clarifying tripartite framework advanced by philosopher Clare Palmer (2013), (though Warwick first discovered it in a 2022 publication) in her discussion of the very issue—killing non-native species—Warwick is treating. That is, ethics based on rights and rules (deontology), virtuous behavior (virtue ethics), or overall consequences (consequentialism). However, he refers to various of these ethical stances, especially deontology and consequentialism, from the very beginning, and he uses the term “utilitarian” for “consequentalist” throughout except on pages 258–259, never explaining that he intends them to be equivalent.