Rapid increases in human population are decreasing biodiversity, including urbanization and coastal settlements, global displacement of people (refugees), and increases in pollution. The human demand for food from the sea promotes overfishing as well as fishing down the food chain, causing direct competition with marine wildlife, including seabirds. Conservation requires identifying the species most at risk and the causes of species declines, and reducing those risks. Conservation is evolving to include community involvement as well as adaptive management whereby data gaps are determined, new data are generated, and management responds accordingly (Buxton et al., 2016). Species living on islands are particularly vulnerable, and many conservationists have proposed that invasive, non-native mammals are the main cause of extinctions of birds on islands (Butchart, Stattersfield & Brooks, 2006). It is intuitive that removal of invasive species that prey on native species should increase their population viability, as Brooke et al. (2017) have shown in the current issue of Animal Conservation. Their analysis is superb, and nicely teases apart the co-factors influencing whether seabird populations increase (usually) or not following successful eradication. But it is also important to place their data within a complex causal system, and to begin to develop both methods and data to examine the multiple effects together, much as health practitioners are forced to examine human health as a complex of the disease, contaminants, susceptibility, and social factors (Smith, 2002). Conservation measures can address multiple objectives, however Brooke et al. (2017) recognize sample size limitations (too few monitoring datasets) inhibiting further study of variable interactions within their study system. Eradication of invasive non-native mammals from islands used by breeding seabirds is one tool of environmental management designed to reduce predation rates, thereby increasing reproductive success and eventual population levels. However, other tools need to be developed to address seabird conservation threats globally. In a recent review, Croxall et al. (2012) listed commercial fisheries, pollution, invasive predators, habitat degradation, and human disturbance as the main threats facing seabirds and leading to local extinction, and this is true whether seabird-nesting islands are coastal or oceanic (Burger, 2018). Climate change may amplify all of these threats, including invasive predators, suggesting that most conservation projects should include climate change (and sea level rise) as a contributing factor. The threat of climate change and concomitant sea level rise, as well as increasing storm severity and frequency are a game-changer for seabirds nesting on islands, as well as for many other endangered and threatened species (Bellard, Leclerc & Courchamp, 2014). Sea level rise reduces nesting habitat, floods nests and burrows, and causes mortality. Climate change shifts food availability, possibly resulting in mismatch between breeding and food. Eradicating invasive mammals from seabird-nesting islands will not work if the island eventually is so degraded by sea level rise and storms that seabirds can no longer nest successfully. Seabird populations fluctuate for various reasons. Often the trends are missed and the causes are never found. For example, considering the seabird populations nesting on the entire Gulf of Mexico indicates that some species (e.g. laughing gulls, Leucophaeus atricilla) are increasing in some states, and decreasing in others (Burger, 2018). Any analysis that examined populations in only one state or region, or on only a few islands (whether predators have been removed or not), will provide a false impression of population changes. Brooke et al. (2017) acknowledged the difficulty of attributing population increases to management without sufficient data on local-, regional- or population-level changes. Determining whether overall populations have increased or merely shifted from one area to another is clearly difficult. However, methods must be developed to do so or we will be unable to prioritize eradication projects in the future, or place their importance within the global threats framework. Continuous post-eradication monitoring is only one essential tool. Brooke et al. (2017) also call attention to the dearth of post-eradication monitoring while recognizing cost, logistics, and the need to apply eradication expertise on additional islands. Because sea level rise will continue and can decrease both nesting and foraging habitat (Galbraith et al., 2014), seabird populations (particularly as a measure of success of conservation measures) must be considered over a large geographical area, and optimally on the global level. In the northeast coast of North America, several coastal-nesting species of seabirds have gradually shifted northward as nesting islands have become unsuitable due to sea level rise (as well as storm severity, Burger & Gochfeld, 2016). Many islands in Chesapeake Bay, and later Barnegat Bay, were gradually eroded by sea level rise and severe storms, and as a consequence terns and gulls abandoned many islands and their populations dropped, whereas over time, populations of terns and gulls increased on Long Island Sound and in Massachusetts. These population shifts were not necessarily ‘due to’ management of island habitats or predator control, although they may have coincided with these management actions on islands farther north. Rather, they occurred as a response to massive habitat loss due to sea level rise and increases in storm severity and frequency, that decreased reproductive success on the islands farther south which were lower in elevation (Burger & Gochfeld, 2016). Reynolds et al. (2015) suggested that sea level rise might also create ecological traps for seabirds nesting on Pacific islands. The Brooke et al. (2017) paper is ground-breaking, and provides critical data demonstrating that the eradication of invasive predators on seabirds-nesting islands is a viable and important conservation measure. Their distinction based on age at first breeding should consider that the ‘immigration’ they observe may be young recruits able to nest earlier than the published age at first breeding, rather than birds that are breeding successfully on nearby islands. Thus, removals create an opportunity rather than a sink. It is up to us as managers and conservationists to add other dimensions to their analysis and place them within the total threat framework. It is also important to develop species conservation plans that address the full range of threats, including the overarching effects of climate change and sea level rise.