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This chapter summarizes the reproductive strategy of the House Sparrow. Although monogamy is the primary mating system of the species, significant rates of extra-pair fertilizations have been identified by DNA-fingerprinting. Both the adaptive and proximate causes of clutch size variation in the species are discussed. Other topics include age at first reproduction, timing of breeding, nest sites, incubation, nesting success, reproductive lifespan, and captive breeding.

Captive breeding represents the last chance of survival for many species faced with imminent extinction in the wild. Captive breeding should be used sparingly because it is sometimes ineffective, and it can harm wild populations both indirectly and directly if not done correctly. There are a variety of crucial genetic issues to be considered in the founding of captive populations: How many individuals? Which source population(s)? A primary genetic goal of captive breeding programs is to minimize genetic change in captivity due to genetic drift and selection because genetic changes in captive populations can reduce the ability of captive individuals to reproduce and survive when returned to the wild. A variety of potentially valuable technologies (e.g., cloning, CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR-associated system), gene drives, etc.) are now available that have the potential to be valuable tools in conservation.

Primates began the arduous journey out of their native countries and into captive collections in the late nineteenth century. However, their survival was severely limited by a lack of natural history knowledge and husbandry requirements. In the decades to follow, primate survivorship and propagation in zoos greatly increased. By the 1980s, captive breeding for most primates was routinely successful, but maintaining genetic diversity became the new impediment to population sustainability in zoos. This can be remedied in part by the inception of regional cooperative breeding programs focused on maintaining genetically and demographically robust populations. Many of today’s zoos have emerged as conservation organizations and have the potential to play an important role in species’ recovery and conservation.

Drawing on ethnographic research of leading conservation biologists, this chapter describes the erosion of the distinctions between species management in captivity and its conservation in wild nature, often referred to among conservationists as in situ and ex situ conservation. Specifically, the chapter explores situations whereby the extinction, or the near extinction, of a species in the wild is evident, and a captive breeding program is initiated to ensure this species’ survival. It present efforts by ex situ conservation groups, typically zoos, to recover such species through captive breeding, as well as the International Union for the Conservation of Nature’s (IUCN) Red List narrative and its emerging “One Plan approach” that promotes an integrated management of wild and captive populations. In effect, the chapter presents the possibility of abandoning the “in” and “out” paradigm in favor of an understanding of conservation that focuses on a holistic, meta-populations management.

In recent years in North America and in other locales, there has been a surge of interest in the status and conservation of amphibian populations. Concern centers on the disappearance or decline of individual populations, species, and even geographic assemblages of amphibians, particularly anurans. Although there is likely no one cause for population declines in many scattered regions or for the deformities reported in midwestern North America, researchers are now feverishly developing monitoring and research programs that can only aid in our understanding of amphibian population dynamics and the importance of amphibians to ecosystem function. Head-starting, relocation, repatriation, and translocation (HS/RRT), often in conjunction with captive breeding, have frequently been suggested as viable options in the conservation of amphibians. This chapter reviews recent projects employing HS/RRT solutions to problems facing imperiled amphibians.

This chapter reviews the recent studies revealing the role of chemical communication in regulating many giant-panda interactions. The identity of marking individuals, their sex and reproductive condition, and their social rank in the community are examples of the message that a panda may transmit via scent. The data presented highlights the importance of chemical communication to giant pandas, and suggests useful applications of scent in the conservation and management of the species, in both the wild and in captivity. There is a clear role in the application of chemical communication for captive breeding programs. The chapter also notes that scent communication in the giant panda is more complex than the simple monitoring of scent marks deposited in the environment.

The ecologic role of marine mammals is explored in this chapter, including food and the feeding relationships of marine mammals and the effects of change on the dynamics of marine ecosystems. Also considered is the effect of humans on marine mammal communities, ranging from oil spills and contamination of the ocean with heavy metals to diseases and global climate change and loss of habitat. Finally, conservation efforts such as captive breeding, provision of critical habitat, and relocation and recovery programs are evaluated.

European mink were once widespread across Eurasia, but now exist only in small isolated populations in parts of their former range. A number of factors likely contributed to the decline but direct inter-specific aggression from non-native American mink has been key. This chapter reviews restoration efforts for this species undertaken over the past 17 years on the (American mink-free) Estonian Island of Hiiumaa (where captive-bred European mink have been released in an attempt to create an island sanctuary) and in Spain (one of the few European countries were a viable population of European mink may persist). It discusses some of the challenges association with reintroduction efforts, including the potential role of personality types, and reviews the status of European mink in Spain, focusing on the threat associated with the current expansion of American mink there and the urgent need for conservation action.

This chapter examines how American zoological gardens responded to the rapid, nearly simultaneous decline of two iconic species at the turn of the nineteenth century: the bison and the passenger pigeon. The North American continent once supported extensive populations of both species, which inspired awe and wonder in the European settlers who encountered them. During the second half of the nineteenth century, however, habitat destruction, competition from exotic species, and especially large-scale commercial exploitation facilitated by newly constructed rail networks produced dramatic declines in both populations. As a result, the bison and the passenger pigeon were both facing extinction by the end of the nineteenth century. Wildlife conservationists successfully mobilized to save the bison, and the New York Zoological Park (opened in 1899) began a captive bison herd that helped repopulate several newly created federal reserves in the West. They failed, however, to rally behind the passenger pigeon, and the last known specimen perished at the Cincinnati Zoo on September 1, 1914. The New York Zoological Park’s captive breeding experiments proved the exception rather than the rule during this period, when zoos remained primarily focused on entertaining and educating the public, rather than trying to save endangered species.

Conservation biology as a discipline focused on endangered species is young and dates only from the late 1970s. Although conservation of endangered species encompasses many different biological disciplines, including behavior, ecology, and genetics, evolutionary considerations always have been emphasized (e.g., Frankel and Soule 1981). Many of the applications of evolutionary concepts to conservation are ones related to genetic variation in small or subdivided populations. However, the critical status of many endangered species makes both more precision and more caution necessary than the general findings for evolutionary considerations. On the other hand, the dire situations of many endangered species often require recommendations to be made on less than adequate data. Overall, one can think of the evolutionary aspects of conservation biology as an applied aspect of the evolution of small populations with the important constraint that any conclusions or recommendations may influence the actual extinction of the populations or species under consideration. From this perspective, all of the factors that influence continuing evolution (i.e., selection, inbreeding, genetic drift, gene flow, and mutation; e.g., Hedrick 2000) are potentially important in conservation. The evolutionary issues of widest concern in conservation biology’”inbreeding depression and maintenance of genetic variation’” can be seen in their simplest form as the joint effects of inbreeding and selection, and of genetic drift and mutation, respectively. However, even in model organisms such as Drosophila, the basis of inbreeding depression and the maintenance of genetic variation are not clearly understood. In addition, findings from model laboratory organisms may not provide good insight into problems in many endangered species, the most visible of which are generally slowly reproducing, large vertebrates with small populations. Here we will first focus on introductions to two important evolutionary aspects of conservation biology: the units of conservation and inbreeding depression. Then, we will discuss studies in two organisms as illustrations of these and related principles’”an endangered fish species, the Gila topminnow, and desert bighorn sheep’”to illustrate some evolutionary aspects of conservation. In the discussion, we will mention some of the other evolutionary topics that are relevant to conservation biology.

Black-footed ferrets were reduced to a remnant population of 10 in 1985 due to diseases (plague, canine distemper), but successful captive breeding and releases have improved the prospects for ferret recovery. Comparisons between black-footed ferrets and Siberian polecats, close relatives that can interbreed and produce fertile offspring, allow the following evolutionary speculation. Predation on ferrets and polecats tends to narrow their niches and promote specialization due to requirements for escape habitats. In Asia, that influence is countered by the larger and more diverse area of steppe and alpine meadow habitats for polecats, and by plague which causes large variation in prey abundance. In North America, the selective pressure favoring specialization in ferrets on prairie dog prey and burrows had no strong counter-force before plague invaded. Plague is an immense challenge to black-footed ferret recovery, and several management tools including vaccines and vector control may be necessary to conserve the species.

This chapter summarizes the overarching principles governing conservation management and reviews approaches that have been used to successfully manage reptile populations worldwide. Management of reptiles requires an integrated landscape approach that incorporates habitats and connections among these at multiple spatial scales, rather than a species-oriented focus. There is no single management approach that is suitable in all instances and for all taxonomic groups. Thus, experimentation, monitoring, and adaptation are necessary to ensure management effectiveness. The simplest approach to reptile conservation is via statutory protection, though habitat protection can also be a viable strategy. Other strategies to consider are captive breeding, or even simply moving the animals out of harm’s way (via relocation, repatriation, translocation; or RRT). Other issues to consider are pest control protocols, biosecurity measures, disease prevention, and so on.

Humans have translocated thousands of nonhuman primates for conservation, welfare, economic, political, aesthetic, religious, and scientific reasons. Translocations that are intended to promote conservation should increase the probability of the establishment of a self-sustaining population of the species and/or restore critical ecological functions. Nine successful conservation-motivated nonhuman primate translocations, involving fewer than 800 individuals, are described. Translocation has not been used extensively as a conservation tool for nonhuman primates, although it may play a larger role in the future. Many primates have been translocated for welfare purposes: to avoid their certain death or to improve their wellbeing. Conservation-motivated translocations are also designed and conducted to maintain wellbeing, but there are inherent risks in moving nonhuman primates to new environments. Body size, niche breadth, and being born in captivity or in the wild are shown to have direct and indirect effects on the probability of success of nonhuman primate translocations.