Black-tailed Godwits are on their way home

As I write this, at the start of March 2020, spring is on its way – and so are limosa Black-tailed Godwits. Many have flown north from wetlands and rice-fields in West Africa and are now fattening and moulting in a small number of sites in Portugal, France and Spain. The vast majority are heading for the Netherlands but a few will ‘bear left’ and end up in East Anglia.

The biggest spring flocks of limosa Black-tailed Godwits are found on the Tagus (or Tejo) Estuary, in Portugal, a site that is under threat from a planned airport development. Swirling flocks of up to 80,000 birds create a wildlife spectacle that attracts an increasing number of tourists. Among these ranks of telescope-wielding birdwatchers is a small band of dedicated colour-ring readers from the Netherlands working on a University of Groningen / Global Flyway Network project. They are looking for marked Black-tailed Godwits (Grutto in Dutch) that are part of their conservation science project; some of these Grutto are old friends, others will have been ringed as chicks and are now heading north for the first time.

This year, the Dutch team working in Portugal in mid-February spotted ten Project Godwit birds – Black-tailed Godwits that belong to the tiny and highly threatened population that breed in the Ouse and Nene Washes. An increasing number of these sightings of English birds are of ‘head-started’ godwits; birds that started life as eggs in nests on the RSPB’s Nene Washes reserve and were then hatched in incubators and reared in captivity at the Wildfowl & Wetland Trust’s Welney reserve. You can read more about head-starting here.

Before telling some fascinating individual stories, here’s a quick reminder that conservation operations in The Netherlands, the UK and elsewhere might be jeopardised by a plan to build a second airport for Lisbon, within the Tagus Estuary – one of the top wetlands in Europe and a critical stopover site for limosa godwits.

Birds v Planes

Millions of euros – and a smaller number of pounds – are spent each year in support of the dwindling populations of limosa Black-tailed Godwits that breed in the Netherlands, here in the UK and in other countries within Europe. Much of the money is helping ‘meadow birds’ in general but there are specific interventions to protect godwit nests and chicks during farming operations in the Netherlands and to boost chick production in England. These huge (and often expensive) conservation efforts are potentially being threatened by a plan to build the so-called Montijo Airport in the heart of the Tagus Estuary. This is where up to 80,000 Black-tailed Godwits gather in spring and several thousand spend the winter. You can read more about the planned airport and the importance of the area to migratory waders and other waterbirds in Tagus estuary – for birds or planes?

Last chance for England’s breeding Black-tailed Godwits

When Project Godwit started in 2017, there were only 38 pairs of Black-tailed Godwit breeding in East Anglia, mostly on the Nene Washes, with a small number on the Ouse Washes. Despite huge efforts by conservation organisations, and the RSPB in particular, productivity was consistently very low. Predation and flooding were the main challenges; there was a real prospect of ageing birds failing to raise enough youngsters to maintain the viability of the population. While work continued to create alternative flood-free breeding areas at the Ouse Washes and to tackle predation issues, these godwits needed a boost. That’s where head-starting comes in; by removing first clutches, incubating the eggs, raising the chicks and releasing them back onto the Nene and Ouse Washes, once fledged, it proved possible to greatly increase the number of young birds that headed south for the winter.

At the start, there was no guarantee that head-starting would work. The first WaderTales blog about Project Godwit was a plea for birdwatchers to look out for colour-ringed, head-started chicks, the second asked whether the released chicks would be able to find their way back to East Anglia and the third celebrated early successes.

1. Special Black-tailed Godwits
2. Site-fidelity in Black-tailed Godwits
3. Head-starting success

The success of these special head-started Black-tailed Godwits has been enjoyed by millions who watch the BBC’s Springwatch series and thousands of visitors to the WWT centre at Welney. In addition, individual godwits have played starring roles in newspaper and magazine articles and on local television news programmes.

Migration

One of the big take-home messages from Project Godwit is that head-started chicks, released back on the Ouse and Nene Washes, soon mix with wild-reared birds and adults.  Information collected so far suggests that head-started birds follow similar migration patterns to the wild godwits.  Most limosa Black-tailed Godwits travel south to countries in West Africa, especially Senegal, and then fly north after Christmas, to Portugal and Spain.  Some may make another stop in France, before reaching their territories. An increasing proportion of the main Dutch population is now wintering in Europe (Should Black-tailed Godwits cross the Sahara?). Dutch and Iberian researchers are using satellite tracking to monitor day-to-day movements (King of the Meadows)

Birds on the Tagus in 2020

Black-tailed Godwits feeding in a Tagus rice-field

Some limosa Black-tailed Godwits spend the winter on the Tagus but big flocks do not start to build until the start of the new year, as birds return from Africa. The ten colour-ringed Project Godwit individuals that were seen by the Dutch team between 2^nd and 10^th of February 2020 were a mixture of old friends and birds that had not been seen on the rice fields before. Flocks of 30,000 or more Black-tailed Godwits can descend upon a single rice-field, post-harvest, to feed on spilt grain and invertebrates. It is not easy to spot colour-ringed birds in the melee of legs, as birds wade through the water, and it is very likely that there were many more Washes birds that were not spotted. The ten Project Godwit birds were seen alongside hundreds being studied by Dutch conservation scientists. So, which individual godwits were seen?

Class of 2017

Two head-started chicks from the first year of the project were seen in February 2020. One of them was YG-GL(E) or Remi (click on her name to read her story), who starred in the WaderTales blog Site-fidelity in Black-tailed Godwits. We know that she is one of the majority of Black-tailed Godwits that fly to West Africa because she was also spotted in Senegal in November 2019. A total of 24 head-started birds were released in the summer of 2017 and six of them have now been seen on the Tagus.

Class of 2018

In the summer of 2018, 38 head-started chicks were released and two of them were seen this February in the Tagus rice-fields. One of these was WG-WL(E) or Hurricane, a bird that spent his first summer near Valencia in Spain before departing in mid-June. Some Black-tailed Godwits fly north in their first spring but many do not. After months of Spanish sunshine, Hurricane may well have flown south with an early flock of post-breeding adults, moving through to West Africa in the late summer,  and that the Dutch team spotted him on his way back to the Washes. Two other head-started birds from the second year of the project have been seen on the Tagus, making a total of four.

Class of 2019

The 48 head-started birds from 2019 are still only a few months old. Some might be on their way back to the Washes but there were no sightings in early February. It has been suggested that birds that do migrate north to breed in their first year might be on a slightly later schedule, so perhaps later teams of Dutch observers might report one or more of these birds.

Wild chicks 2017-2019

The Project Godwit team try to ring as many as possible of the wild-reared chicks on the Nene Washes, so that they can compare their behaviour patterns to those of the captive-reared group. Two of the wild-reared birds have been seen on the Tagus; a chick from 2018 was reported in both 2019 and 2020, and a chick from 2019 was seen in the autumn of 2019.

Earlier chicks

Two members of the Dutch team of colour-ring readers: Rienk Jelle Hibma & Teade de Boer

The RSPB has been studying Black-tailed Godwits for over twenty years. One of the very early chicks was spotted in the rice-fields this February. LG-RL(E) was ringed 21 years ago and she had previously been reported in the Tagus estuary in the springs of 2017, 2018 and 2019, and in the autumn of 2018. Black-tailed Godwits are known to live for up to 25 years.

Ringed as adults

RSPB researchers also ring adults by catching them on their nests. Four birds ringed in this way were seen on the Portuguese rice-fields in February 2020. Adding in four head-started chicks, and two chicks that was raised in the wild, this makes a total of ten birds from the Ouse and Nene Washes that are known to have visited the Tagus Estuary during this spring.

There are two colour-ringed birds in this photograph

One that won’t be seen again

RY-OL(E) was ringed in 2002 and spotted in the Tagus in February 2018. She has been a key contributor to Project Godwit over the last few years, fledging two chicks in the wild in 2018 and three in 2019. Additionally, she provided four extra young godwits via the head-starting process in 2018. Her metal-ringed leg was recently found in a Peregrine nest in Brighton. Presumably she became a meal for a young Peregrine in the late summer of 2019.

Conservation importance of the Tagus Estuary

In February, the Tagus is thought to hold half of what is left of the Dutch population of Black-tailed Godwits, when up to 80,000 birds move around the estuary in huge flocks. Colour-ring reports and sighting probabilities suggest that around half of the Project Godwit birds, heading for the Ouse and Nene Washes, may also rely on the mud-flats and surrounding rice-fields in the early spring.

Project Godwit has already given a terrific boost to the Black-tailed Godwits breeding in England, with the number of pairs up from 38 in 2017 to 45 in 2019, and it seems ridiculous that much of the good work could be put at risk if Montijo Airport is built. It is sad that a five-year project, that has involved over 20 dedicated RSPB and WWT staff , together with local volunteers and observers in the UK, Europe and Africa, might be in jeopardy.

Project Godwit has received major funding from the EU LIFE Nature Programme, HSBC 150^th Anniversary Fund, Natural England, the Heritage Lottery Fund (through the Back from the Brink Programme) and Leica UK. The Dutch team of colour-ring readers in February 2020 was: Jan Vegelin, Kees de Jager, Egbert van der Velde, Rienk Jelle Hibma, Teade de Boer, Bob Loos & Jacob de Vries.  Their work is directed by Jos Hooijmeijer and funded by the University of Groningen and the Global Flyway Network.

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WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research.  Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.

@grahamfappleton