Using satellite imagery, drone imagery, and ground counts, we have assembled the very first comprehensive global population evaluate of Chinstrap penguins (Pygoscelis antarctica) at 3.42 (95th-percentile CI: <2.98, 4.00>) million breeding pairs across 375 extant colonies. Twenty-three previously well-known Chinstrap penguin colonies are uncovered to be absent or extirpated. We recognize five new colonies, and also 21 additional colonies formerly unreported and likely to let go by previous surveys. Restricted or imprecise historic data prohibit our evaluate of population change in ~ 35% of all Chinstrap penguin colonies. Of colonies for i beg your pardon a comparison can be made to historical counts in the 1980s, 45% have actually probably or definitely declined and also 18% have probably or certainly increased. Several huge colonies in the southern Sandwich Islands, where conditions apparently continue to be favorable for Chinstrap penguins, cannot be assessed against a historical benchmark. Our populace assessment provides a comprehensive baseline because that quantifying future transforms in Chinstrap penguin abundance, sheds new light ~ above the environmental vehicle drivers of Chinstrap penguin populace dynamics in Antarctica, and contributes to continuous monitoring and also conservation efforts at a time of climate change and comes to over declining krill abundance in the southern Ocean.

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Chinstrap penguins (Pygoscelis antarctica) are plentiful in Antarctica, v past estimates ranging from 3–8 million reproduction pairs, and also are considered a types of “least concern” by BirdLife International1, but the populace dynamics of this types are no well understood and several studies have actually highlighted far-ranging declines at monitored sites2,3,4,5,6. Due to the fact that Chinstrap penguins swarm in remote and rugged areas, on-the-ground census work is difficult, expensive, and also sporadic. As a result, documentation of global Chinstrap penguin abundance and distribution has, to date, to be unavoidably incomplete, and also many areas where Chinstrap penguins breed have actually not been saw or surveyed since the early on 1980s. Without an accurate count, the is difficult to form a complete picture of the species’ distribution and also assess its population dynamics over time.

The literature on Chinstrap penguin abundance and population trends suggests that Chinstrap penguin number in Antarctica increased during the years leading up to the 1970s7,8 and subsequently declined. Due to the fact that the 1980s, reproduction populations in some areas have been reported come have decreased by > 50%2,3,4,5,6,8,9, with noteworthy exceptions in the south Sandwich Islands, at southern Georgia Island, and also in a couple of sites near the southern level of the Chinstrap penguin’s range4,10. Since of their dependence top top krill (Euphausia spp.) and also fish (Pleuragramma antarctica), Chinstrap penguins have the right to be regarded as “marine sentinels” because that quantifying environmental adjust in the southern Ocean11. Despite considerable interest in the dynamics of this varieties as a window into the Southern s ecosystem12, reliable populace estimates for Chinstrap penguins space lacking, both globally and also regionally. To update counts would certainly improve estimates of krill usage by Chinstrap penguins and benefit spatial to plan efforts, including the style of safeguarded areas.

Accurate, longitudinal data are additionally needed to test hypotheses attempting to describe why both Chinstrap and also Adélie (Pygoscelis adeliae) penguin populations around the west Antarctic Peninsula have decreased for the past half century while Gentoo penguins (Pygoscelis papua) have increased, in many cases at swarms where the species nest next by side (e.g.8,13,14). Renowned hypotheses indicate that penguin populations are driven by krill availability, however krill biomass is broadly influenced by climate change, krill fishing, and also the recovery of whale and also seal populations—the collective effects of which are an overwhelming to disentangle indigenous the view of penguin dynamics8,15,16,17. Other potential impacts, consisting of tourism, extreme weather events, and disease outbreaks, may be crucial at neighborhood scales or for quick periods of time, but are less compelling explanations for the widespread transforms observed across the Antarctic penguins3,18,19.

The objective of this paper is to resolve two research questions: (1) What is the global population and also distribution the Chinstrap penguins? and also (2) just how does updated info on Chinstrap penguin abundance and distribution support or refute current hypotheses of penguin populace dynamics approximately the west Antarctic Peninsula? This record provides a condition report ~ above our efforts to assemble all the available information ~ above Chinstrap penguin distribution, abundance, and population trends over the previous 40 years. We have actually used released data, extr unpublished data indigenous our own recent ar surveys, and also estimates derived from high-resolution <0.31–3.0 m/pixel> satellite imagery obtained from Maxar, Planet, and also Google Earth, and medium-resolution <30.0 m/pixel> Landsat imagery and unmanned aerial device (UAS) imagery. When unavoidably incomplete, this report offers the most an extensive catalog to day of Chinstrap penguin colonies, their precise locations, and their population trends (see Supplementary Information), and also identifies priority areas for future surveys. Finally, we comment on how these results fit right into the current dispute surrounding vehicle drivers of penguin population trends in the Antarctic Peninsula region.

We calculation the global population the Chinstrap penguins at 3.42 (95th-percentile CI: <2.98, 4.00>) million breeding pairs (Table 1) in 375 extant reproduction sites, not including recent extirpations. All inspection details, updated populace estimates, historic benchmarks, and also estimates of populace change are noted in the Supplementary Information.

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Most Chinstrap penguin nests are in the southwest Atlantic ar of the southerly Ocean, which contains the Antarctic Peninsula and associated islands, including the southern Orkney Islands, southern Sandwich Islands, and South Georgia Island (Fig. 1). The southernmost Antarctic Peninsula nests are located on the north side of Marguerite Bay, in ~ a latitude of approximately 67.8′ S. Globally, the Chinstrap penguin’s selection also includes little colonies on Bouvet Island and in the Balleny archipelago (Fig. 2). That 398 complete sites, us were able to verify the places of 364 native satellite imagery (Table 2). Colonies were present, or presumed present, in ~ 332 sites, with secondary 42 swarms unable to be assessed with available literature and imagery. This complete includes 26 previously unreported nests that, i beg your pardon the exemption of several tiny colonies in the far south, were likely present yet overlooked by vault surveys. There were 23 swarms that to be either evidenced as having actually no reproduction Chinstrap penguins or where we presume, however have no confirmed, absence—all that which represent potential extirpations. For 260 sites with updated diversity estimates, 43.8% had the greatest level of precision (N1, ± 5% accuracy) and 42.3% had the lowest (N5, nearest bespeak of magnitude), following embraced standards (e.g.20,21). While we did identify several formerly unreported colonies, the identification of very small colonies (Figure 1

Figure developed with ArcMap variation 10.6.1 and also Adobe Illustrator 2020 version 24.2.1.