29 Apr 2019

Migration route of secretive Steppe Whimbrel discovered

The Steppe Whimbrel is the rarest and least understood member of the highly threatened Numeniini tribe (curlews and godwits). But considering they were believed to be extinct 25 years ago, it’s unsurprising that we know so little about them. A newly published report is beginning to fill in the gaps in our knowledge.

Spot the difference: the Steppe Whimbrel is identified by its white underwings © Callan Cohen & Gary Allport
Spot the difference: the Steppe Whimbrel is identified by its white underwings © Gary Allport
By Cressida Stevens

The story of the Steppe Whimbrel Numenius phaeopus alboaxillaris is a bizarre one. There is a very real risk in conservation that birds can go extinct before we even know they exist, or know enough about them to make efforts to protect them. Very little was known about the Steppe Whimbrel – a rare sub-species of the Whimbrel Numenius phaeopus - before it was declared extinct in 1994. However, recent sightings have revealed the Steppe Whimbrel lives on, and we now have a second chance to research and rescue this enigmatic bird.

The Steppe Whimbrel is one of four subspecies of the Whimbrel. The Whimbrel itself has an IUCN rating of Least Concern – but were the Steppe Whimbrel to be its own species, it would be classified as Critically Endangered. A recent review of the subspecies’ status estimates that there are a mere 100 individuals left, at most, and the population trend is declining.

For 30 years, this wader managed to escape the notice of humans and, like a lot of lost wildlife, it began to experience cultural extinction. This is where people stop looking for an animal, it is soon omitted from modern field guides and its existence is forgotten. But three years after the birds were consigned to history, they were re-found in Russia.

It is often said that you find something when you stop looking. In this case, it was actually during search efforts for the closely-related Slender-billed Curlew Numenius tenuirostris in 1997, that researchers stumbled upon Steppe Whimbrels close to the Ural Mountains in Russia. This initial discovery was followed by regular sightings in the late 1990s and early 2000s. However, being a migratory bird, little can be understood about it when only seen during part of the year. It was not until February 2016, that this bird was rediscovered at its wintering grounds in Africa, for the first time on the continent since 1965.

Gary Allport (BirdLife International) and colleagues had been observing and photographing a flock of Common Whimbrels Numenius phaeopus phaeopus on a beach in Maputo, Mozambique. But only when he returned from the site and looked over the pictures, did Gary realise that one bird stood out from the rest, matching the description of the very rare Steppe Whimbrel subspecies. Gary tells of the extraordinary experience: “It is amazing to think that such a rare and little known bird was sitting on the public beach in Maputo, the capital city of Mozambique, right under our nose.” Distinguishing between subspecies is not easy, but the Steppe Whimbrel differs in appearance with white underwings, white axillaries and fewer markings on its belly. Gary consulted experts, who confirmed his judgement, thereby launching a whole new opportunity for research.

Gary Allport discovered the Steppe Whimbrel when looking over his photographs © Callan Cohen & Gary Allport

The next step was to go back to the site in an attempt to track down their anomalous bird. Upon returning, excitement grew as not only did they find the bird, but also a second Steppe Whimbrel. The race was now on to gather as much information as possible from these two birds - a male and a female - before they took flight back to their Asian breeding grounds.

With the publishing of this research in Wader Study, we are finally filling in the gaps in our knowledge of this bird. Regular surveys of the beach in Mozambique have provided information on social interaction, feeding behaviour and timing of migration. In addition, equipping the male with a satellite tracker has revealed for the first time the route this subspecies takes and that Steppe Whimbrels are further set apart from Common Whimbrels by migrating one month sooner. The tagged male made quite a remarkable journey, covering almost 4,700 kilometres in just six days.

The opportunistic study of these two individual birds is of course not enough to establish reliable trends and information on the Steppe Whimbrel. In order to learn more, researchers are encouraging the public in Eastern Africa to look out for white underwings among flocks of whimbrels and curlews and photograph any suspected Steppe Whimbrels.

Currently, there is no conservation effort aimed specifically at this subspecies, which is only to be expected: it’s very difficult to conserve an animal about which so little is known. This new research has made an exciting advance in equipping conservationists with some of the vital information needed, if they are to attempt a rescue of this bird.

The paper is published in Wader Study here: http://dx.doi.org/10.18194/ws.00126 (paywall).

The open access PDF is available on Researchgate here: https://www.researchgate.net/publication/330657425_Local_site_use_and_first_northbound_migration_track_of_non-breeding_Steppe_Whimbrel_Numenius_phaeopus_alboaxillaris_Lowe_1921

For a more in-depth insight, see Graham Appleton's blog here: https://wadertales.wordpress.com/2019/01/26/in-search-of-steppe-whimbrel/