Blog by Dr Jen Smart, Principal Conservation Scientist, RSPB Centre for Conservation Science
At the RSPB Centre for Conservation Science there are around 60 full time scientists working on conservation problems around the world. My team specialise in tackling the problems faced by breeding waders and Project Godwit is one of our big projects over the next few years. Project Godwit is a partnership between the RSPB and the Wildfowl and Wetlands Trust (WWT) and aims to secure the future for breeding black-tailed godwits in the UK.
Photo: There are now fewer than 50 pairs of black-tailed godwits in the UK and most of them breed in the Fens at two locations, the Nene and the Ouse Washes.
How do we go about trying to save a species?
Well we do have a step-by-step process which is all about having the right information before moving onto the next step. The first step is knowing which conservation problems are important or in species conservation, having good monitoring data to alert us to a species in trouble (step 1). For a species in trouble, identifying the cause/s of decline is critical (step 2) and once we have an idea about the cause this can often point to possible solutions (step 3). The final step is about applying the solution in the real world and testing whether it solves the problem for that species (step 4). Sometimes the first solution doesn’t work, and we have to go back to the beginning of step 3 and start again.
Saving the black-tailed godwit
Godwits are reliant on nature reserves and this means, we have outstanding long-term monitoring data that not only tells us where godwits breed and how many but also gives us information about how many chicks are fledging each year. There are now fewer than 50 pairs in the UK and most of them breed in the Fens at two locations, the Nene and the Ouse Washes.
Numbers at the Ouse Washes declined dramatically during the 80s and 90s and research identified an increase in the frequency of flooding during the breeding season as the cause of that decline. The solution was to create flood free grassland for godwits adjacent to the Ouse Washes but that process took a long time and although there are now three areas of grassland managed for godwits by WWT and the RSPB (Lady Fen, Pilot Project and Coveney).
Information about the number of chicks fledging each year suggested that low breeding success was the cause of that decline. Godwits only need to produce one chick every second year but data over the last few years shows they are only producing one chick every five years. Monitoring data therefore alerted us to the species being in trouble and we instigated a couple of years of research to find out why they were not producing enough young.
Godwits nest on the ground so their nests are vulnerable, and they produce chicks that are flightless for the first 30 days or so and again are vulnerable. We set out to measure nest survival and chick survival and to understand what was happening to nests and chicks that failed. This sort of field detective work takes a lot of time just watching to find nests or to follow chicks, but we also use technology and colour marking of the birds to help us. Tiny temperature loggers tell us the date and time of nest failure and miniature nest cameras on a sample of nests can identify the cause of failure. Having parent birds colour marked allows us to follow broods from hatching to hopefully fledging and having chicks colour marked allows us to identify which chicks fledge or not.
What did we find? About 40% of nests hatched each year and of the nests that failed 80% were eaten by predators and out loggers told us that in one year most predation happened at night so must be nocturnal mammals whereas in the other year more predation occurred in the day and is most likely avian predators or mammals that are active in the day and nest cameras identified a whole range of predators. Chick survival was very low in both years and it is much trickier to know what happened to these highly mobile and difficult to observe chicks, but avian predators were involved in one year.
Applying and testing solutions to address the low breeding success
Low breeding success driven by high predation on nests and chicks is the cause of the decline in godwits at the Nene Washes, so we needed solutions that would reduce the impacts of a diverse group of predators on this species. Here I am just going to talk about two of the solutions we are testing.
Does predator fencing reduce nest predation?
Our research showed that mammal predators are important and other RSPB research has shown predator fencing to be an effective way to reduce the impacts but its difficult to permanently fence the Nene as it often floods in winter. Monitoring of mammal movements using trail cameras also suggested that they use the track down the centre of the site to access the wader breeding fields. We wondered whether simply restricting access off the track with predator proof gates would work or whether you need to combine those gates with blocks of fields that are also electric fenced during the breeding season. To date these trials have shown consistently lower nest predation rates for nests in fields that are protected by both gates and electric fences. For now we are continuing with protecting the key godwit nesting areas during the breeding season while considering what the longer term options for fencing might be at this site but we have been pleased to see a slight upturn in the breeding success of godwits which is likely the combined result of all of our conservation interventions.
Photo: Predator fencing to be an effective way to reduce the impacts of mammal predators on black-tailed godwits
Head-starting to boost breeding success and fast track site colonisation
Head-starting is the process where early clutches are taken from the wild and incubated, hatched and reared in captivity with fledged chicks released into the wild at fledging age. It has two aims: boosting breeding success and fast tracking the colonisation of other sites. Hatching and rearing of the chicks take place at Welney under the expertise of the WWT team. Head-started godwits have been released in two years so far. In 2017, 26 birds were reared and released at Lady Fen and in 2018, 38 godwits were reared at Lady Fen with 15 released at the Nene Washes and 23 released at Lady Fen.
It is too soon to tell exactly how successful this technique will be, but early indications are really promising. In terms of boosting breeding success, in 2017, 0.18 wild chicks fledged per pair of godwits but head-starting boosted that to 0.86 chicks per pair and in 2018, 0.46 wild chicks fledged per pair but head-starting boosted that to 1.43. And what about colonisation of sites within the project area? To date we have had 20 of the head-started godwits return to the Fens during the breeding season with 14 at Lady Fen, 5 at the Nene Washes and 1 at the Pilot Project and this is contributing to the population increases we have seen at all project sites over the last two years.
Photo: Headstarted chick at WWT Welney
Measuring the success of these conservation interventions
Much of what we do to understand the success of these conservation solutions and any long-term effects relies on us being able to follow our birds throughout their lives, who is breeding with who, where are birds breeding, how successful are they etc etc. We are really interested in their survival, migration and dispersal because this all has consequences for what happens during the breeding season. We are using a range of techniques to be able to follow these birds.
The most simple and low tech of all the methods is colour ringing. Being able to observe a bird and simply from the combination of coloured rings to know who you are looking at and their history is fantastic and to receive emails from the network of godwit colour ring observers across the world to say they have seen a Project Godwit bird in Spain or Portugal or even west Africa is incredible. All observers receive a full history for birds they report. Colour ringing is already telling us a huge amount, but sometime colour ringing is not enough.
For example, during the breeding season the long grass can make it really difficult to observe rings, so we increasingly use pit tags to identify who is breeding where and who belongs to which nest. A pit tag is the same as the pet id devices that your vet can scan except our pit tags are inserted in bird rings and we read them by putting a tiny scanner in the godwit nests which logs the presence of birds with pit tags – genius!
Colour ringing has also told us a lot about the migration of these godwits, but the downside with colour rings is that all you know is that the bird was observed in a given location on a given date. We really want to know the migration routes and time spent in different locations and especially want to know whether the head-started birds (who never have any contact with their parents) are actually making sensible migratory decisions. To do this we have fitted a sample of wild and head started godwits with tiny tracking devices (geolocators) attached to their rings that will allows us to plot their migration routes in the coming years.
Project Godwit is a 5-year project and we are now part way through our third breeding season. We have learnt a huge amount already that is really starting to help this beautiful species and the whole project team is crossing their fingers and toes in that hope that the early signs of success that we can see continue during the remainder of this project. This really is a humongous team effort and I must pay homage to all my RSPB and WWT colleagues who are working round the clock right now to save this species. The photo below is a small part of that team looking particularly happy having just released some head-started godwits at the Nene Washes for the first-time last year.
Photo: The Project Godwit team
Really interesting read, thank you! There are hardy any articles available that show the practical side of conservation. But could you help me understand what does it mean that "Godwits only need to produce one chick every second year" What do you mean, by need? Because godwits usually produce eggs each year. Thank you!