Last of the Curlews: Part II

“The beauty and genius of a work of art may be reconceived, though its first material expression be destroyed; a vanished harmony may yet again inspire the composer; but when the last individual of a race of living beings breathes no more, another heaven and another earth must pass before such a one can be again.” William Beebe, in ‘The Bird, Its Form and Function’.

Beebe’s sapient quote introduces my 1963 copy of Bodsworth’s Last of the Curlews, a novel that artistically describes the likely extinction of the Eskimo Curlew in the 19th century in response to widespread agricultural expansion and conversion, and hunting. Now we have published a paper that documents and quantifies the likely extinction of the Slender-billed Curlew for reasons that feel hauntingly familiar—widespread agricultural expansion and conversion, and (possibly) hunting. Its loss represents only the third bird species to spend a large part of its annual cycle in the Western Palaearctic to be known to have gone globally extinct since 1500, after the Great Auk (last seen alive in 1844) and the Canarian Oystercatcher (last collected in 1913 and reported as absent in 1940s).

For most of the past century, Slender-billed Curlew was probably on a trajectory to extinction. As early as the 1940s, alarm at this possibility was raised (Stresemann & Grote 1943) but a response was slow to come; not until 1988 did it feature as a species of high conservation concern, and not until 1996 was a species action plan produced (Gretton 1996). It came too late. The last documented (photographed) and unanimously accepted observation of the species was made in 1995, at Merja Zerga (Morocco), which legions of birdwatchers visited in the early 1990s in a grim foreshadowing of what was to come.

Figure 1. Slender-billed Curlew specimens © Natural History Museum.

Our study combines information from specimens (>400), observations (confirmed and unconfirmed; nearly 900), surveys (on both the non-breeding and suspected breeding grounds) and consideration of likely threats (their acuity and spatial extent). These data were applied to three models that quantify the probability of a species’ extinction (see paper for details). The results are bleak—but predictable. All models concluded, with high probability, that Slender-billed Curlew is extinct; the Solow and Beet Model estimated there was a less than a 0.000005% chance the species survived to 2022, and suggested that the species probably went extinct in the 1990s, confirming what observers of the Merja Zerga bird(s) must have strongly suspected at the time: they were watching one of the very last individuals of a species.

The threats responsible for the extinction of Slender-billed Curlew will always be difficult to elucidate, but the extensive loss of wetlands and conversion of large areas of its putative breeding areas to cropland in the 19th and 20th centuries, as well as possibly hunting, are the most likely drivers.

But there are worrying signs that this may not be the final chapter in the chronicle of curlew extinctions. There are now estimated to be 60% fewer Far Eastern Curlews than there were only 20 years ago (Rogers et al. 2023). In the UK, the population of breeding Eurasian Curlew halved between 1995 and 2022 (Heywood et al. 2024). More broadly, migratory shorebirds across all flyways are in serious trouble. The world’s c.440 remaining Spoon-billed Sandpipers continue to dwindle, perhaps inexorably, by 5% a year (Green et al. 2024). Grey Plover and Curlew Sandpiper are both estimated to have declined by >30% over the past 15–20 years, comprising two of the 16 migratory shorebird species that had their global extinction risk on the IUCN Red List increased by BirdLife International in October 2024.

So how do we respond? Each documented bird extinction (as of 2024, there have been 164 since 1500) is rightly met with cries of ‘We must not let this happen again!’. Followed invariably by it happening again. As my colleague, and co-author, Nicola Crockford (Principal Policy Officer for the RSPB) aptly put it: “Just as carbon in the atmosphere is a measure of international efforts to combat climate change, the status of migratory species is an indicator of the success of international efforts to conserve biodiversity. The extinction of the Slender-billed Curlew is as much a clarion call for greatly enhanced action for nature as the floods, fires and droughts devastating the planet are for action to combat climate change.” As I write, 60% of the world’s bird species are declining and more than 1,300 are threatened with extinction (BirdLife International 2024). Let us hope that the extinction of Slender-billed Curlew does instigate the urgency and scale of intervention that is needed. And let us hope that in 20 years I am not sat at my desk penning Last of the Curlews: Part III.